Word milk comes from

The term “milk” comes from “Old English meoluc (West Saxon), milc (Anglian), from Proto-Germanic *meluks “milk” (source also of Old Norse mjolk, Old Frisian melok, Old Saxon miluk, Dutch melk, Old High German miluh, German Milch, Gothic miluks)”. The term dairy relates to animal milk and animal milk production.

How did history gets its name?

The word history comes from the Ancient Greek ἱστορία (historía), meaning “inquiry”, “knowledge from inquiry”, or “judge”. History was borrowed from Latin (possibly via Old Irish or Old Welsh) into Old English as stær (“history, narrative, story”), but this word fell out of use in the late Old English period.

What is the difference between history from herstory?

As nouns the difference between herstory and history is that herstory is (nonstandard) history that emphasizes the role of women, or that is told from a woman’s (or from a feminist) point of view while history is the aggregate of past events.

What is history in simple words?

History is the study of past events. People know what happened in the past by looking at things from the past including sources (like books, newspapers, and letters) and artifacts (like pottery, tools, and human or animal remains.) A person who studies history is called a historian.

What is history in my own words?

History is the study of the past – specifically the people, societies, events and problems of the past – as well as our attempts to understand them. It is a pursuit common to all human societies.

What is history define it in your own words?

The word “history” has several meanings. It can mean everything that’s ever happened in the past. Thus a second definition: history as the written record of what happened in the past or put another way, history is what historians write.

How do you describe history?

Here are some adjectives for history: narrative and critical, informal but true, wrong, impartial, fabulous natural, _institutional, long and very widespread, exact subsequent, _impartial, geological and natural, experiential emotional, legendary and traditional, british natural, incredibly turbulent, practical natural …

What words do historians use?

Terms in this set (12)

• artifact. Objects made or used by people.
• corroborate. To corroborate is to confirm.
• investigate. Examine.
• primary source.
• secondary source.
• contextualize.
• interpret.
• evidence.

What is a rich history?

11 adj A rich life or history is one that is interesting because it is full of different events and activities.

What does deep history mean?

Deep history is a term for the distant past of the human species. Proponents of deep history argue for a definition of history that rests not upon the invention of writing, but upon the evolution of anatomically modern humans.

What’s a word for trying to impress someone?

Frequently Asked Questions About impress Some common synonyms of impress are affect, influence, strike, sway, and touch. While all these words mean “to produce or have an effect upon,” impress stresses the depth and persistence of the effect.

I say I say I say, these be related to AGr. molubdos «lead», xalc «bronze» and other metal slash color words, melaccha, malaka, belo, bled, Blei, lead, black, malz, malmen, walzen, wühlen, möhlen. … Thus Via Galaxis amy be the silk road modulo the Seima Turbo phenomenon middle of the bronze age, and maybe earlier elsewhere. The xalx word at least is a likely wanderword. A symbolic connection between milk and metal is ice, nearly homophone at least in Germanic, but also cp. gelati, xlad, etc. Maybe kyklos also belonged here.

I can’t explain that. It would be quite the quantum leap. As lo g as the PIE roots have no internal derivation, all bets are open, and the odds don’t look too bad even that they are imperfect, depending on the branches’ individual etymologies, especially the obvious folk etymologies like for the milky way. worst bollocks I ever layed my eyes on

---

cf. https://en.m.wikipedia.org/wiki/Iron_Pass «According to the legend, a princess of the Kingdom of Yanqi called Tzouhla had fallen in love with a poor herdsman named Tayir. The royal court opposed the relationship and a minister Karehan convinced the king to have Tayir killed.»

Similar, espania if from Phoenician SPN may have meant iron, or north… or rabbit. Compare Yumen Pass: «Yumen guan 玉門關 and Yang guan 陽關 are derived from: yu 玉 = ‘jade’ + men 門 = ‘gate’, ‘door’; and yang 陽 = ‘sunny side’, ‘south side of a hill’, ‘north side of a river,’ and guan 關 = ‘frontier-passes», «It was originally called the ‘Square City'». I wane say the legend of Hera’s nipple having been bit off whence she spilled the milk of the shmilky-way might recall corporal punishment that involved amputations (or precautious breast ironing and the like). The Tang Dynasty is a bit late for origin of a shared IE myth.

Posted by Johannes on 28 March 2010

This entry was posted on 28 March 2010 at 12:48 am and is filed under M.
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white liquid produced by the mammary glands of mammals

A glass of milkCows in a rotary milking parlor

Milkis a nutrient -rich liquid food produced in the mammary glands of mammals. It is the primary source of nutrition for infant mammals (including humans who are breastfed ) before they are able to digest other types of food. Early-lactation milk contains colostrum, which carries the mother’s antibodies to its young and can reduce the risk of many diseases. It contains many other nutrients including protein and lactose. Interspecies consumption of milk is not uncommon, particularly among humans, many of whom consume the milk of other mammals.

As an agricultural product, dairy milk is extracted from farm animals. Dairy farms produced around 730 million tonnes of milk in 2011, from 260 million dairy cows.India is the world’s largest producer of milk, and is the leading exporter of skimmed milk powder, yet it exports few other milk products. The ever-increasing rise in domestic demand for dairy products and a large demand-supply gap could lead to India being a net importer of dairy products in the future. New Zealand, Germany and the Netherlands are the largest exporters of milk products. China and Russia were the world’s largest importers of milk and milk products until 2016 when both countries became self-sufficient, contributing to a worldwide glut of milk.

Throughout the world, more than six billion people consume milk and milk products. Between 750 and 900 million people live in dairy farming households.

Contents

• 1 Etymology and terminology
  • 1.1 Non-dairy milks
• 2 Types of consumption
  • 2.1 Nutrition for infant mammals
  • 2.2 Food product for humans
• 3 History
  • 3.1 Industrialization
  • 3.2 Overproduction
• 4 Sources
  • 4.1 Other animal-based sources
• 5 Production worldwide
  • 5.1 Production yields
  • 5.2 Price
• 6 Environmental impact
• 7 Physical and chemical properties
  • 7.1 pH
  • 7.2 Lipids
  • 7.3 Proteins
    • 7.3.1 Caseins
  • 7.4 Salts, minerals, and vitamins
    • 7.4.1 Calcium phosphate structure
  • 7.5 Sugars and carbohydrates
  • 7.6 Miscellaneous contents
  • 7.7 Appearance
• 8 Processing
  • 8.1 Pasteurization
    • 8.1.1 Filtration
  • 8.2 Creaming and homogenization
  • 8.3 UHT
• 9 Nutrition and health
  • 9.1 Cow’s milk
  • 9.2 Nutritional value
  • 9.3 Medical research
  • 9.4 Calcium absorption
  • 9.5 Milk and acne
  • 9.6 Lactose intolerance
  • 9.7 Possible harms
  • 9.8 Flavored milk in U.S. schools
• 10 Evolution of lactation
• 11 Bovine growth hormone supplementation
• 12 Criticism
• 13 Varieties and brands
  • 13.1 Reduction or elimination of lactose
  • 13.2 Additives and flavoring
  • 13.3 Distribution
    • 13.3.1 Australia and New Zealand
    • 13.3.2 India
    • 13.3.3 Pakistan
    • 13.3.4 United Kingdom
    • 13.3.5 United States
  • 13.4 Packaging
  • 13.5 Spoilage and fermented milk products
• 14 Use in other food products
• 15 In language and culture
• 16 Non-culinary uses
• 17 See also
• 18 Notes
• 19 References
• 20 Further reading
• 21 External links

Etymology and terminology

The term «milk» comes from «Old English meoluc (West Saxon), milc (Anglian), from Proto-Germanic *meluks «milk» (source also of Old Norse mjolk, Old Frisian melok, Old Saxon miluk, Dutch melk, Old High German miluh, German Milch, Gothic miluks)».

In food use, from 1961, the term milk has been defined under Codex Alimentarius standards as: «the normal mammary secretion of milking animals obtained from one or more milkings without either addition to it or extraction from it, intended for consumption as liquid milk or for further processing.» The term dairy relates to animal milk and animal milk production.

A substance secreted by pigeons to feed their young is called «crop milk » and bears some resemblance to mammalian milk, although it is not consumed as a milk substitute.

Non-dairy milks

The definition above precludes non-animal products which resemble dairy milk in color and texture, such as almond milk, coconut milk, rice milk, and soy milk. In English, the word «milk» has been used to refer to «milk-like plant juices» since 1200 AD. Traditionally a variety of non-dairy products have been described with the word milk, including the traditional digestive remedies milk of magnesia and milk of bismuth.Latex, the complex inedible emulsion that exudes from the stems of certain plants, is generally described as milky and is often sold as «rubber milk» because of its white appearance. The word latex itself is derived from the Spanish word for milk.

A 2018 survey by the International Food Information Council Foundation suggests consumers in the United States do not typically confuse plant-based milk analogues with animal milk and dairy products. In the US, (mostly plant-based) milk alternatives now command 13% of the «milk» market, leading the US dairy industry to attempt, multiple times, to sue producers of dairy milk alternatives, to have the name «milk» limited to animal milk, so far without success. The Food and Drug Administration generally supports restricting the term «milk», while the US Department of Agriculture supports the continued use of terms such as «soymilk». In the European Union, words such as milk, butter, cheese, cream and yogurt are legally restricted to animal products, with exceptions such as coconut milk, almond milk, peanut butter, and ice cream.

Production of milk substitutes from vats of brewer’s yeast is under development by organizations including Impossible Foods, Perfect day, and the biohacker group Real Vegan Cheese. Some components would be chemically identical to those in animal-derived milk; others, such as lactose, to which many people are allergic, may be substituted. In 2019 Perfect Day sold the first ice cream made with non-animal whey protein.

Types of consumption

Milk consumption occurs in two distinct overall types: a natural source of nutrition for all infant mammals and a food product obtained from other mammals for consumption by humans of all ages.

Nutrition for infant mammals

Breastfeeding to provide a mother’s milkA goat kid feeding on its mother’s milk

In almost all mammals, milk is fed to infants through breastfeeding, either directly or by expressing the milk to be stored and consumed later. The early milk from mammals is called colostrum. Colostrum contains antibodies that provide protection to the newborn baby as well as nutrients and growth factors. The makeup of the colostrum and the period of secretion varies from species to species.

For humans, the World Health Organization recommends exclusive breastfeeding for six months and breastfeeding in addition to other food for up to two years of age or more. In some cultures it is common to breastfeed children for three to five years, and the period may be longer.

Fresh goats’ milk is sometimes substituted for breast milk, which introduces the risk of the child developing electrolyte imbalances, metabolic acidosis, megaloblastic anemia, and a host of allergic reactions.

Food product for humans

The Holstein Friesian cattle is the dominant breed in industrialized dairy farms today.A bowl of milk for the shaman rite. Buryatia, Russia.

In many cultures, especially in the West, humans continue to consume milk beyond infancy, using the milk of other mammals (especially cattle, goats and sheep) as a food product. Initially, the ability to digest milk was limited to children as adults did not produce lactase, an enzyme necessary for digesting the lactose in milk. People therefore converted milk to curd, cheese and other products to reduce the levels of lactose. Thousands of years ago, a chance mutation spread in human populations in Europe that enabled the production of lactase in adulthood. This mutation allowed milk to be used as a new source of nutrition which could sustain populations when other food sources failed. Milk is processed into a variety of products such as cream, butter, yogurt, kefir, ice cream, and cheese. Modern industrial processes use milk to produce casein, whey protein, lactose, condensed milk, powdered milk, and many other food-additives and industrial products.

Whole milk, butter and cream have high levels of saturated fat. The sugar lactose is found only in milk, forsythia flowers, and a few tropical shrubs. The enzyme needed to digest lactose, lactase, reaches its highest levels in the human small intestine after birth and then begins a slow decline unless milk is consumed regularly. Those groups who do continue to tolerate milk, however, often have exercised great creativity in using the milk of domesticated ungulates, not only of cattle, but also sheep, goats, yaks, water buffalo, horses, reindeer and camels. India is the largest producer and consumer of cattle and buffalo milk in the world.

Per capita consumption of milk and milk products in selected countries in 2011

Country	Milk (liters)	Cheese (kg)	Butter (kg)
Ireland	135.6	6.7	2.4
Finland	127.0	22.5	4.1
United Kingdom	105.9	10.9	3.0
Australia	105.3	11.7	4.0
Sweden	90.1	19.1	1.7
Canada	78.4	12.3	2.5
United States	75.8	15.1	2.8
Europe	62.8	17.1	3.6
Brazil	55.7	3.6	0.4
France	55.5	26.3	7.5
Italy	54.2	21.8	2.3
Germany	51.8	22.9	5.9
Greece	49.1	23.4	0.7
Netherlands	47.5	19.4	3.3
India	39.5	—	3.5
China	9.1	—	0.1

History

Drinking milk in Germany in 1932

Humans first learned to consume the milk of other mammals regularly following the domestication of animals during the Neolithic Revolution or the development of agriculture. This development occurred independently in several global locations from as early as 9000–7000 BC in Mesopotamia to 3500–3000 BC in the Americas. People first domesticated the most important dairy animals – cattle, sheep and goats – in Southwest Asia, although domestic cattle had been independently derived from wild aurochs populations several times since. Initially animals were kept for meat, and archaeologist Andrew Sherratt has suggested that dairying, along with the exploitation of domestic animals for hair and labor, began much later in a separate secondary products revolution in the fourth millennium BC. Sherratt’s model is not supported by recent findings, based on the analysis of lipid residue in prehistoric pottery, that shows that dairying was practiced in the early phases of agriculture in Southwest Asia, by at least the seventh millennium BC.

From Southwest Asia domestic dairy animals spread to Europe (beginning around 7000 BC but did not reach Britain and Scandinavia until after 4000 BC), and South Asia (7000–5500 BC). The first farmers in central Europe and Britain milked their animals. Pastoral and pastoral nomadic economies, which rely predominantly or exclusively on domestic animals and their products rather than crop farming, were developed as European farmers moved into the Pontic-Caspian steppe in the fourth millennium BC, and subsequently spread across much of the Eurasian steppe. Sheep and goats were introduced to Africa from Southwest Asia, but African cattle may have been independently domesticated around 7000–6000 BC. Camels, domesticated in central Arabia in the fourth millennium BC, have also been used as dairy animals in North Africa and the Arabian Peninsula. The earliest Egyptian records of burn treatments describe burn dressings using milk from mothers of male babies. In the rest of the world (i.e., East and Southeast Asia, the Americas and Australia) milk and dairy products were historically not a large part of the diet, either because they remained populated by hunter-gatherers who did not keep animals or the local agricultural economies did not include domesticated dairy species. Milk consumption became common in these regions comparatively recently, as a consequence of European colonialism and political domination over much of the world in the last 500 years.

In the Middle Ages, milk was called the «virtuous white liquor» because alcoholic beverages were safer to consume than water.

Industrialization

Preserved Express Dairies three-axle milk tank wagon at the Didcot Railway Centre, based on an SR chassis

The growth in urban population, coupled with the expansion of the railway network in the mid-19th century, brought about a revolution in milk production and supply. Individual railway firms began transporting milk from rural areas to London from the 1840s and 1850s. Possibly the first such instance was in 1846, when St Thomas’s Hospital in Southwark contracted with milk suppliers outside London to ship milk by rail. The Great Western Railway was an early and enthusiastic adopter, and began to transport milk into London from Maidenhead in 1860, despite much criticism. By 1900, the company was transporting over 25 million gallons annually. The milk trade grew slowly through the 1860s, but went through a period of extensive, structural change in the 1870s and 1880s.

Milk transportation in Salem, Tamil Nadu

Urban demand began to grow, as consumer purchasing power increased and milk became regarded as a required daily commodity. Over the last three decades of the 19th century, demand for milk in most parts of the country doubled or, in some cases, tripled. Legislation in 1875 made the adulteration of milk illegal – This combined with a marketing campaign to change the image of milk. The proportion of rural imports by rail as a percentage of total milk consumption in London grew from under 5% in the 1860s to over 96% by the early 20th century. By that point, the supply system for milk was the most highly organized and integrated of any food product.

The first glass bottle packaging for milk was used in the 1870s. The first company to do so may have been the New York Dairy Company in 1877. The Express Dairy Company in England began glass bottle production in 1880. In 1884, Hervey Thatcher, an American inventor from New York, invented a glass milk bottle, called «Thatcher’s Common Sense Milk Jar,» which was sealed with a waxed paper disk. Later, in 1932, plastic-coated paper milk cartons were introduced commercially.

In 1863, French chemist and biologist Louis Pasteur invented pasteurization, a method of killing harmful bacteria in beverages and food products. He developed this method while on summer vacation in Arbois, to remedy the frequent acidity of the local wines. He found out experimentally that it is sufficient to heat a young wine to only about 50–60 °C (122–140 °F) for a brief time to kill the microbes, and that the wine could be nevertheless properly aged without sacrificing the final quality. In honor of Pasteur, the process became known as «pasteurization». Pasteurization was originally used as a way of preventing wine and beer from souring. Commercial pasteurizing equipment was produced in Germany in the 1880s, and producers adopted the process in Copenhagen and Stockholm by 1885.

Overproduction

Continued improvements in the efficiency of milk production led to a worldwide glut of milk by 2016. Russia and China became self-sufficient and stopped importing milk. Canada has tried to restrict milk production by forcing new farmers/increased capacity to «buy in» at C$ 24,000 per cow. Importing milk is prohibited. The European Union theoretically stopped subsidizing dairy farming in 2015. Direct subsidies were replaced by «environmental incentives» which results in the government buying milk when the price falls to € 200 per 1,000 liters (220 imp gal; 260 U.S. gal). The United States has a voluntary insurance program that pays farmers depending upon the price of milk and the cost of feed.

Sources

Modern dairy farm in Norway

The females of all mammal species can by definition produce milk, but cow’s milk dominates commercial production. In 2011, FAO estimates 85% of all milk worldwide was produced from cows. Human milk is not produced or distributed industrially or commercially; however, human milk banks collect donated human breastmilk and redistribute it to infants who may benefit from human milk for various reasons (premature neonates, babies with allergies, metabolic diseases, etc.) but who cannot breastfeed.

In the Western world, cow’s milk is produced on an industrial scale and is by far the most commonly consumed form of milk. Commercial dairy farming using automated milking equipment produces the vast majority of milk in developed countries. Dairy cattle such as the Holstein have been bred selectively for increased milk production. About 90% of the dairy cows in the United States and 85% in Great Britain are Holsteins. Other dairy cows in the United States include Ayrshire, Brown Swiss, Guernsey, Jersey and Milking Shorthorn (Dairy Shorthorn).

Other animal-based sources

Other significant sources of milkGoats (2% of world’s milk)Buffaloes (11%)

Aside from cattle, many kinds of livestock provide milk used by humans for dairy products. These animals include water buffalo, goat, sheep, camel, donkey, horse, reindeer and yak. The first four respectively produced about 11%, 2%, 1.4% and 0.2% of all milk worldwide in 2011.

In Russia and Sweden, small moose dairies also exist.

According to the U.S. National Bison Association, American bison (also called American buffalo) are not milked commercially; however, various sources report cows resulting from cross-breeding bison and domestic cattle are good milk producers, and have been used both during the European settlement of North America and during the development of commercial Beefalo in the 1970s and 1980s.

Swine are almost never milked, even though their milk is similar to cow’s milk and perfectly suitable for human consumption. The main reasons for this are that milking a sow’s numerous small teats is very cumbersome, and that sows can not store their milk as cows can. A few pig farms do sell pig cheese as a novelty item; these cheeses are exceedingly expensive.

Production worldwide

Largest milk producers in the world. in 2018

Rank	Country	Production. (metric tons )
1	India	186,143,000
—	European Union	167,256,000
2	United States	98,646,000
3	Pakistan	45,623,000
4	Brazil	35,539,000
5	China	31,592,000
6	Russia	31,527,000
7	Turkey	22,791,000
8	New Zealand	21,372,000
World	842,989,000

Top ten cow milk producers. in 2013

Rank	Country	Production. (metric tons )
1	United States	91,271,058
2	India	60,600,000
3	China	35,310,000
4	Brazil	34,255,236
5	Germany	31,122,000
6	Russia	30,285,969
7	France	23,714,357
8	New Zealand	18,883,000
9	Turkey	16,655,009
10	United Kingdom	13,941,000

Top ten sheep milk producers. in 2013

Rank	Country	Production. (metric tons)
1	China	1,540,000
2	Turkey	1,101,013
3	Greece	705,000
4	Syria	684,578
5	Romania	632,582
6	Spain	600,568
7	Sudan	540,000
8	Somalia	505,000
9	Iran	470,000
10	Italy	383,837

Top ten goat milk producers. in 2013

Rank	Country	Production. (metric tons)
1	India	5,000,000
2	Bangladesh	2,616,000
3	Sudan	1,532,000
4	Pakistan	801,000
5	Mali	720,000
6	France	580,694
7	Spain	471,999
8	Turkey	415,743
9	Somalia	400,000
10	Greece	340,000

Top ten buffalo milk producers. in 2013

Rank	Country	Production. (metric tons)
1	India	70,000,000
2	Pakistan	24,370,000
3	China	3,050,000
4	Egypt	2,614,500
5	Nepal	1,188,433
6	Myanmar	309,000
7	Italy	194,893
8	Sri Lanka	65,000
9	Iran	65,000
10	Turkey	51,947

In 2012, the largest producer of milk and milk products was India followed by the United States of America, China, Pakistan and Brazil. All 28 European Union members together produced 153.8 million tonnes of milk in 2013, the largest by any politico -economic union.

Increasing affluence in developing countries, as well as increased promotion of milk and milk products, has led to a rise in milk consumption in developing countries in recent years. In turn, the opportunities presented by these growing markets have attracted investments by multinational dairy firms. Nevertheless, in many countries production remains on a small scale and presents significant opportunities for diversification of income sources by small farms. Local milk collection centers, where milk is collected and chilled prior to being transferred to urban dairies, are a good example of where farmers have been able to work on a cooperative basis, particularly in countries such as India.

Production yields

FAO reports Israel dairy farms are the most productive in the world, with a yield of 12,546 kilograms (27,659 lb) milk per cow per year. This survey over 2001 and 2007 was conducted by ICAR (International Committee for Animal Recording) across 17 developed countries. The survey found that the average herd size in these developed countries increased from 74 to 99 cows per herd between 2001 and 2007. A dairy farm had an average of 19 cows per herd in Norway, and 337 in New Zealand. Annual milk production in the same period increased from 7,726 to 8,550 kg (17,033 to 18,850 lb) per cow in these developed countries. The lowest average production was in New Zealand at 3,974 kg (8,761 lb) per cow. The milk yield per cow depended on production systems, nutrition of the cows, and only to a minor extent different genetic potential of the animals. What the cow ate made the most impact on the production obtained. New Zealand cows with the lowest yield per year grazed all year, in contrast to Israel with the highest yield where the cows ate in barns with an energy-rich mixed diet.

The milk yield per cow in the United States was 9,954 kg (21,945 lb) per year in 2010. In contrast, the milk yields per cow in India and China – the second and third largest producers – were respectively 1,154 kg (2,544 lb) and 2,282 kg (5,031 lb) per year.

Price

It was reported in 2007 that with increased worldwide prosperity and the competition of bio-fuel production for feed stocks, both the demand for and the price of milk had substantially increased worldwide. Particularly notable was the rapid increase of consumption of milk in China and the rise of the price of milk in the United States above the government subsidized price. In 2010 the Department of Agriculture predicted farmers would receive an average of $1.35 per U.S. gallon of cow’s milk (35 cents per liter), which is down 30 cents per gallon from 2007 and below the break-even point for many cattle farmers.

Environmental impact

Mean greenhouse gas emissions for one glass (200g) of different milks

Milk Types	Greenhouse Gas Emissions (kg CO2-Ceqper 200g)
Cow’s Milk	0.62
Rice Milk	0.23
Soy Milk	0.21
Oat Milk	0.19
Almond Milk	0.16

Mean water footprint for one glass (200g) of different milks

Milk Types	Water Use (L per 200g)
Cow’s Milk	131
Almond Milk	74
Rice Milk	56
Oat Milk	9
Soy Milk	2

Mean land use for one glass (200g) of different milks

Milk Types	Land Use (m per 200g)
Cow’s Milk	1.81
Oat Milk	0.25
Soy Milk	0.23
Almond Milk	0.19
Rice Milk	0.14

The consumption of cow’s milk poses numerous threats to the natural environment. Compared to plant milks, cow’s milk requires the most land and water, and its production results in the greatest amount of greenhouse gas (GHG) emissions, air pollution, and water pollution. A 2010 UN report, Assessing the Environmental Impacts of Consumption and Production, argued that animal products, including dairy, «in general require more resources and cause higher emissions than plant-based alternatives». It proposed a move away from animal products to reduce environmental damage.

The global water footprint of animal agriculture is 2,422 billion cubic meters of water (one-fourth of the total global water footprint), 19 percent of which is related to dairy cattle. A 2012 study found that 98 percent of milk’s footprint can be traced back to the cows food.

A 2010 Food and Agriculture Organization report found that the global dairy sector contributes to four percent of the total global anthropogenic GHG emissions. This figure includes emissions allotted to milk production, processing and transportation, and the emissions from fattening and slaughtering dairy cows. The same report found that 52 percent of the GHGs produced by dairy cattle is methane, and nitrous oxide makes up for another 27 percent of dairy cattle’s GHG emission. It is estimated that cows produce between 250 and 500 liters of methane a day. Methane has a heat-trapping potential nearly 100 times larger than carbon dioxide, and nitrous oxide has a global warming potential almost 300 times greater than carbon dioxide.

Physical and chemical properties

Butterfat is a triglyceride (fat) formed from fatty acids such as myristic, palmitic, and oleic acids.

Milk is an emulsion or colloid of butterfat globules within a water-based fluid that contains dissolved carbohydrates and protein aggregates with minerals. Because it is produced as a food source for the young, all of its contents provide benefits for growth. The principal requirements are energy (lipids, lactose, and protein), biosynthesis of non-essential amino acids supplied by proteins (essential amino acids and amino groups), essential fatty acids, vitamins and inorganic elements, and water.

pH

The pH of milk ranges from 6.4 to 6.8 and it changes over time. Milk from other bovines and non-bovine mammals varies in composition, but has a similar pH.

Lipids

Initially milk fat is secreted in the form of a fat globule surrounded by a membrane. Each fat globule is composed almost entirely of triacylglycerols and is surrounded by a membrane consisting of complex lipids such as phospholipids, along with proteins. These act as emulsifiers which keep the individual globules from coalescing and protect the contents of these globules from various enzymes in the fluid portion of the milk. Although 97–98% of lipids are triacylglycerols, small amounts of di- and monoacylglycerols, free cholesterol and cholesterol esters, free fatty acids, and phospholipids are also present. Unlike protein and carbohydrates, fat composition in milk varies widely in the composition due to genetic, lactational, and nutritional factor difference between different species.

Like composition, fat globules vary in size from less than 0.2 to about 15 micrometers in diameter between different species. Diameter may also vary between animals within a species and at different times within a milking of a single animal. In unhomogenized cow’s milk, the fat globules have an average diameter of two to four micrometers and with homogenization, average around 0.4 micrometers. The fat-soluble vitamins A, D, E, and K along with essential fatty acids such as linoleic and linolenic acid are found within the milk fat portion of the milk.

Proteins

Normal bovine milk contains 30–35 grams of protein per liter of which about 80% is arranged in casein micelles. Total proteins in milk represent 3.2% of its composition (nutrition table).

Caseins

The largest structures in the fluid portion of the milk are «casein micelles» : aggregates of several thousand protein molecules with superficial resemblance to a surfactant micelle, bonded with the help of nanometer-scale particles of calcium phosphate. Each casein micelle is roughly spherical and about a tenth of a micrometer across. There are four different types of casein proteins: αs1-, αs2-, β-, and κ-caseins. Most of the casein proteins are bound into the micelles. There are several competing theories regarding the precise structure of the micelles, but they share one important feature: the outermost layer consists of strands of one type of protein, k-casein, reaching out from the body of the micelle into the surrounding fluid. These kappa-casein molecules all have a negative electrical charge and therefore repel each other, keeping the micelles separated under normal conditions and in a stable colloidal suspension in the water-based surrounding fluid.

Milk contains dozens of other types of proteins beside caseins and including enzymes. These other proteins are more water-soluble than caseins and do not form larger structures. Because the proteins remain suspended in whey remaining when caseins coagulate into curds, they are collectively known as whey proteins. Lactoglobulin is the most common whey protein by a large margin. The ratio of caseins to whey proteins varies greatly between species; for example, it is 82:18 in cows and around 32:68 in humans.

Ratio of caseins to whey proteins in milk of nine mammals

Species	Ratio
Human	29.7:70.3 – 33.7:66.3
Bovine	82:18
Caprine	78:22
Ovine	76:24
Buffalo	82:18
Equine	52:48
Camel	73:27 – 76:24
Yak	82:18
Reindeer	80:20 – 83:17

Salts, minerals, and vitamins

Minerals or milk salts, are traditional names for a variety of cations and anions within bovine milk. Calcium, phosphate, magnesium, sodium, potassium, citrate, and chloride are all included as minerals and they typically occur at concentration of 5–40 mM. The milk salts strongly interact with casein, most notably calcium phosphate. It is present in excess and often, much greater excess of solubility of solid calcium phosphate. In addition to calcium, milk is a good source of many other vitamins. Vitamins A, B6, B12, C, D, K, E, thiamine, niacin, biotin, riboflavin, folates, and pantothenic acid are all present in milk.

Calcium phosphate structure

For many years the most accepted theory of the structure of a micelle was that it was composed of spherical casein aggregates, called submicelles, that were held together by calcium phosphate linkages. However, there are two recent models of the casein micelle that refute the distinct micellular structures within the micelle.

The first theory attributed to de Kruif and Holt, proposes that nanoclusters of calcium phosphate and the phosphopeptide fraction of beta-casein are the centerpiece to micellular structure. Specifically in this view, unstructured proteins organize around the calcium phosphate giving rise to their structure and thus no specific structure is formed.

The second theory proposed by Horne, the growth of calcium phosphate nanoclusters begins the process of micelle formation but is limited by binding phosphopeptide loop regions of the caseins. Once bound, protein-protein interactions are formed and polymerization occurs, in which K-casein is used as an end cap, to form micelles with trapped calcium phosphate nanoclusters.

Some sources indicate that the trapped calcium phosphate is in the form of Ca9(PO4)6; whereas, others say it is similar to the structure of the mineral brushite CaHPO4 -2H2O.

Sugars and carbohydrates

A simplified representation of a lactose molecule being broken down into glucose (2) and galactose (1)

Milk contains several different carbohydrate including lactose, glucose, galactose, and other oligosaccharides. The lactose gives milk its sweet taste and contributes approximately 40% of whole cow’s milk’s calories. Lactose is a disaccharide composite of two simple sugars, glucose and galactose. Bovine milk averages 4.8% anhydrous lactose, which amounts to about 50% of the total solids of skimmed milk. Levels of lactose are dependent upon the type of milk as other carbohydrates can be present at higher concentrations than lactose in milks.

Miscellaneous contents

Other components found in raw cow’s milk are living white blood cells, mammary gland cells, various bacteria, and a large number of active enzymes.

Appearance

Both the fat globules and the smaller casein micelles, which are just large enough to deflect light, contribute to the opaque white color of milk. The fat globules contain some yellow-orange carotene, enough in some breeds (such as Guernsey and Jersey cattle) to impart a golden or «creamy» hue to a glass of milk. The riboflavin in the whey portion of milk has a greenish color, which sometimes can be discerned in skimmed milk or whey products. Fat-free skimmed milk has only the casein micelles to scatter light, and they tend to scatter shorter-wavelength blue light more than they do red, giving skimmed milk a bluish tint.

Processing

Milk products and productions relationships (click to enlarge)

In most Western countries, centralized dairy facilities process milk and products obtained from milk, such as cream, butter, and cheese. In the U.S., these dairies usually are local companies, while in the Southern Hemisphere facilities may be run by large multi-national corporations such as Fonterra.

Pasteurization

Pasteurization is used to kill harmful pathogenic bacteria by heating the milk for a short time and then immediately cooling it. Types of pasteurized milk include full cream, reduced fat, skim milk, calcium enriched, flavored, and UHT. The standard high temperature short time (HTST) process of 72 °C for 15 seconds completely kills pathogenic bacteria in milk, rendering it safe to drink for up to three weeks if continually refrigerated. Dairies print best before dates on each container, after which stores remove any unsold milk from their shelves.

A side effect of the heating of pasteurization is that some vitamin and mineral content is lost. Soluble calcium and phosphorus decrease by 5%, thiamin and vitamin B12 by 10%, and vitamin C by 20%. Because losses are small in comparison to the large amount of the two B-vitamins present, milk continues to provide significant amounts of thiamin and vitamin B12. The loss of vitamin C is not nutritionally significant, as milk is not an important dietary source of vitamin C.

Filtration

Microfiltration is a process that partially replaces pasteurization and produces milk with fewer microorganisms and longer shelf life without a change in the taste of the milk. In this process, cream is separated from the skimmed milk and is pasteurized in the usual way, but the skimmed milk is forced through ceramic microfilters that trap 99.9% of microorganisms in the milk (as compared to 99.999% killing of microorganisms in standard HTST pasteurization ). The skimmed milk then is recombined with the pasteurized cream to reconstitute the original milk composition.

Ultrafiltration uses finer filters than microfiltration, which allow lactose and water to pass through while retaining fats, calcium and protein. As with microfiltration, the fat may be removed before filtration and added back in afterwards.Ultrafiltered milk is used in cheesemaking, since it has reduced volume for a given protein content, and is sold directly to consumers as a higher protein, lower sugar content, and creamier alternative to regular milk.

Creaming and homogenization

A milking machine in action

Upon standing for 12 to 24 hours, fresh milk has a tendency to separate into a high-fat cream layer on top of a larger, low-fat milk layer. The cream often is sold as a separate product with its own uses. Today the separation of the cream from the milk usually is accomplished rapidly in centrifugal cream separators. The fat globules rise to the top of a container of milk because fat is less dense than water.

The smaller the globules, the more other molecular-level forces prevent this from happening. The cream rises in cow’s milk much more quickly than a simple model would predict: rather than isolated globules, the fat in the milk tends to form into clusters containing about a million globules, held together by a number of minor whey proteins. These clusters rise faster than individual globules can. The fat globules in milk from goats, sheep, and water buffalo do not form clusters as readily and are smaller to begin with, resulting in a slower separation of cream from these milks.

Milk often is homogenized, a treatment that prevents a cream layer from separating out of the milk. The milk is pumped at high pressures through very narrow tubes, breaking up the fat globules through turbulence and cavitation. A greater number of smaller particles possess more total surface area than a smaller number of larger ones, and the original fat globule membranes cannot completely cover them. Casein micelles are attracted to the newly exposed fat surfaces.

Nearly one-third of the micelles in the milk end up participating in this new membrane structure. The casein weighs down the globules and interferes with the clustering that accelerated separation. The exposed fat globules are vulnerable to certain enzymes present in milk, which could break down the fats and produce rancid flavors. To prevent this, the enzymes are inactivated by pasteurizing the milk immediately before or during homogenization.

Homogenized milk tastes blander but feels creamier in the mouth than unhomogenized. It is whiter and more resistant to developing off flavors. Creamline (or cream-top) milk is unhomogenized. It may or may not have been pasteurized. Milk that has undergone high-pressure homogenization, sometimes labeled as «ultra-homogenized», has a longer shelf life than milk that has undergone ordinary homogenization at lower pressures.

UHT

Ultra Heat Treatment (UHT), is a type of milk processing where all bacteria are destroyed with high heat to extend its shelf life for up to 6 months, as long as the package is not opened. Milk is firstly homogenized and then is heated to 138 degrees Celsius for 1–3 seconds. The milk is immediately cooled down and packed into a sterile container. As a result of this treatment, all the pathogenic bacteria within the milk are destroyed, unlike when the milk is just pasteurized. The milk will now keep for up for 6 months if unopened. UHT milk does not need to be refrigerated until the package is opened, which makes it easier to ship and store. But in this process there is a loss of vitamin B1 and vitamin C and there is also a slight change in the taste of the milk.

Nutrition and health

The composition of milk differs widely among species. Factors such as the type of protein; the proportion of protein, fat, and sugar; the levels of various vitamins and minerals; and the size of the butterfat globules, and the strength of the curd are among those that may vary. For example:

• Human milk contains, on average, 1.1% protein, 4.2% fat, 7.0% lactose (a sugar), and supplies 72 kcal of energy per 100 grams.
• Cow’s milk contains, on average, 3.4% protein, 3.6% fat, and 4.6% lactose, 0.7% minerals and supplies 66 kcal of energy per 100 grams. See also Nutritional value further on

Donkey and horse milk have the lowest fat content, while the milk of seals and whales may contain more than 50% fat.

Milk composition analysis, per 100 grams

Constituents	Unit	Cow	Goat	Sheep	Water. buffalo
Water	g	87.8	88.9	83.0	81.1
Protein	g	3.2	3.1	5.4	4.5
Fat	g	3.9	3.5	6.0	8.0
—-Saturated fatty acids	g	2.4	2.3	3.8	4.2
—-Monounsaturated fatty acids	g	1.1	0.8	1.5	1.7
—-Polyunsaturated fatty acids	g	0.1	0.1	0.3	0.2
Carbohydrate (i.e. the sugar form of lactose )	g	4.8	4.4	5.1	4.9
Cholesterol	mg	14	10	11	8
Calcium	mg	120	100	170	195
Energy	kcal	66	60	95	110
kJ	275	253	396	463

Nutritional content of cow, soy, almond and oat milks
Nutrient value. per 243 g cup	Cow milk. (whole, vitamin D added)	Soy milk (unsweetened;. calcium, vitamins A and D added)	Almond milk. (unsweetened)	Oat milk. (unsweetened)
Energy, kJ (kcal)	620 (149)	330 (80)	160 (39)	500 (120)
Protein (g)	7.69	6.95	1.55	3
Fat (g)	7.93	3.91	2.88	5
Saturated fat (g)	4.55	0.5	0	0.5
Carbohydrate (g)	11.71	4.23	1.52	16
Fiber (g)	0	1.2	0	2
Sugars (g)	12.32	1	0	7
Calcium (mg)	276	301	516	350
Potassium (mg)	322	292	176	390
Sodium (mg)	105	90	186	140
Vitamin B 12 (µg)	1.10	2.70	0	1.2
Vitamin A (IU)	395	503	372	267
Vitamin D (IU)	124	119	110	144
Cholesterol (mg)	24	0	0	0

Cow’s milk

These compositions vary by breed, animal, and point in the lactation period.

Milk fat percentages

Cow breed	Approximate percentage
Jersey	5.2
Zebu	4.7
Brown Swiss	4.0
Holstein-Friesian	3.6

The protein range for these four breeds is 3.3% to 3.9%, while the lactose range is 4.7% to 4.9%.

Milk fat percentages may be manipulated by dairy farmers’ stock diet formulation strategies. Mastitis infection can cause fat levels to decline.

Nutritional value

Nutrient contents in %DV of common foods (raw, uncooked) per 100 g

	Protein	Fiber	Vitamins	Minerals
Food	DV	Q	DV	A	B1	B2	B3	B5	B6	B9	B12	Ch.	C	D	E	K	Ca	Fe	Mg	P	K	Na	Zn	Cu	Mn	Se
cooking Reduction %				10	30	20	25		25	35	0	0	30				10	15	20	10	20	5	10	25
Corn	20	55	6	1	13	4	16	4	19	19	0	0	0	0	0	1	1	11	31	34	15	1	20	10	42	0
Rice	14	71	1.3	0	12	3	11	20	5	2	0	0	0	0	0	0	1	9	6	7	2	0	8	9	49	22
Wheat	27	51	40	0	28	7	34	19	21	11	0	0	0	0	0	0	3	20	36	51	12	0	28	28	151	128
Soybean(dry)	73	132	31	0	58	51	8	8	19	94	0	24	10	0	4	59	28	87	70	70	51	0	33	83	126	25
Pigeon pea(dry)	42	91	50	1	43	11	15	13	13	114	0	0	0	0	0	0	13	29	46	37	40	1	18	53	90	12
Potato	4	112	7.3	0	5	2	5	3	15	4	0	0	33	0	0	2	1	4	6	6	12	0	2	5	8	0
Sweet potato	3	82	10	284	5	4	3	8	10	3	0	0	4	0	1	2	3	3	6	5	10	2	2	8	13	1
Spinach	6	119	7.3	188	5	11	4	1	10	49	0	4.5	47	0	10	604	10	15	20	5	16	3	4	6	45	1
Dill	7	32	7	154	4	17	8	4	9	38	0	0	142	0	0	0	21	37	14	7	21	3	6	7	63	0
Carrots	2		9.3	334	4	3	5	3	7	5	0	0	10	0	3	16	3	2	3	4	9	3	2	2	7	0
Guava	5	24	18	12	4	2	5	5	6	12	0	0	381	0	4	3	2	1	5	4	12	0	2	11	8	1
Papaya	1	7	5.6	22	2	2	2	2	1	10	0	0	103	0	4	3	2	1	2	1	7	0	0	1	1	1
Pumpkin	2	56	1.6	184	3	6	3	3	3	4	0	0	15	0	5	1	2	4	3	4	10	0	2	6	6	0
Sunflower oil	0		0	0	0	0	0	0	0	0	0	0	0	0	205	7	0	0	0	0	0	0	0	0	0	0
Egg	25	136	0	10	5	28	0	14	7	12	22	45	0	9	5	0	5	10	3	19	4	6	7	5	2	45
Milk	6	138	0	2	3	11	1	4	2	1	7	2.6	0	0	0	0	11	0	2	9	4	2	3	1	0	5
Chicken Liver	34	149	0	222	20	105	49	62	43	147	276		30	0	4	0	1	50	5	30	7	3	18	25	13	78
%DV = % daily value i.e. % of DRI (Dietary Reference Intake ) Note: All nutrient values including protein and fiber are in %DV per 100 grams of the food item. Significant values are highlighted in light Gray color and bold letters. Cooking reduction = % Maximum typical reduction in nutrients due to boiling without draining for ovo-lacto-vegetables group Q = Quality of Protein in terms of completeness without adjusting for digestability.

Cow’s milk (whole)

Nutritional value per 100 g (3.5 oz)
Energy	252 kJ (60 kcal)
Carbohydrates	5.26 g
Sugars lactose	5.26 g 5.26 g
Fat	3.25 g
Saturated	1.865 g
Monounsaturated	0.812 g
Polyunsaturated	0.195 g
Protein	3.22 g
Tryptophan	0.075 g
Threonine	0.143 g
Isoleucine	0.165 g
Leucine	0.265 g
Lysine	0.140 g
Methionine	0.075 g
Cystine	0.017 g
Phenylalanine	0.147 g
Tyrosine	0.152 g
Valine	0.192 g
Arginine	0.075 g
Histidine	0.075 g
Alanine	0.103 g
Aspartic acid	0.237 g
Glutamic acid	0.648 g
Glycine	0.075 g
Proline	0.342 g
Serine	0.107 g
Vitamins	Quantity%DV
Vitamin A equiv.	6%46 μg
Thiamine (B1)	4%0.044 mg
Riboflavin (B2)	15%0.183 mg
Vitamin B12	19%0.45 μg
Choline	3%14.3 mg
Vitamin D	0%2 IU
Minerals	Quantity%DV
Calcium	11%113 mg
Magnesium	3%10 mg
Potassium	3%132 mg
Sodium	3%43 mg
Other constituents	Quantity
Water	88.32 g
100 mL corresponds to 103 g.
Units μg = micrograms • mg = milligrams IU = International units
Percentages are roughly approximated using US recommendations for adults.. Source: USDA Nutrient Database

Processed cow’s milk was formulated to contain differing amounts of fat during the 1950s. One cup (250 mL) of 2%-fat cow’s milk contains 285 mg of calcium, which represents 22% to 29% of the daily recommended intake (DRI) of calcium for an adult. Depending on its age, milk contains 8 grams of protein, and a number of other nutrients (either naturally or through fortification ) including:

• Biotin
• Iodine
• Magnesium
• Pantothenic acid
• Potassium
• Riboflavin
• Selenium
• Thiamine
• Vitamin A
• Vitamin B12
• Vitamins D
• Vitamin K

Medical research

Overall, cow’s milk can be useful to improve a diet which is otherwise of poor quality, but for a diet which is otherwise healthy, it is redundant or possibly harmful.

There is no good evidence that drinking milk helps prevent bone fractures, even though the American government recommends it for that purpose.

A 2008 review found evidence suggesting that consumption of milk is effective at promoting muscle growth. Some studies have suggested that conjugated linoleic acid, which can be found in dairy products, is an effective supplement for reducing body fat.

Calcium absorption

Calcium from dairy products has a greater bioavailability than calcium from certain vegetables, such as spinach, that contain high levels of calcium-chelating agents, but a similar or lesser bioavailability than calcium from low-oxalate vegetables such as kale, broccoli, or other vegetables in the genus Brassica.

Milk and acne

A 2009 meta-analysis concluded that milk consumption is associated with acne.

Lactose intolerance

Lactose, the disaccharide sugar component of all milk, must be cleaved in the small intestine by the enzyme lactase, in order for its constituents, galactose and glucose, to be absorbed. Lactose intolerance is a condition in which people have symptoms due to not enough of the enzyme lactase in the small intestines. Those affected vary in the amount of lactose they can tolerate before symptoms develop. These may include abdominal pain, bloating, diarrhea, gas, and nausea. Severity depends on the amount a person eats or drinks. Those affected are usually able to drink at least one cup of milk without developing significant symptoms, with greater amounts tolerated if drunk with a meal or throughout the day.

Lactose intolerance does not cause damage to the gastrointestinal tract. There are four types: primary, secondary, developmental, and congenital. Primary lactose intolerance is when the amount of lactase decline as people age. Secondary lactose intolerance is due to injury to the small intestine such as from infection, celiac disease, inflammatory bowel disease, or other diseases. Developmental lactose intolerance may occur in premature babies and usually improves over a short period of time. Congenital lactose intolerance is an extremely rare genetic disorder in which little or no lactase is made from birth. When lactose intolerance is due to secondary lactase deficiency, treatment of the underlying disease allows lactase activity to return to normal levels. Lactose intolerance is different from a milk allergy.

The number of people with lactose intolerance is unknown. The number of adults who cannot produce enough lactase in their small intestine varies markedly in different populations. Since lactase’s only function is the digestion of lactose in milk, in most mammal species the activity of the enzyme is dramatically reduced after weaning. Within most human populations, however, some individuals have developed, by natural evolution, the ability to maintain throughout their life high levels of lactose in their small intestine, as an adaptation to the consumption of nonhuman milk and dairy products beyond infancy. This ability, which allows them to digest lactose into adulthood, is called lactase persistence. The distribution of people with lactase persistence is not homogeneous in the world. For instance, those people with lactase persistence are more than 90% of the population in North Europe, and as low as 5% in parts of Asia and Africa.

Possible harms

Milk and dairy products have the potential for causing serious infection in newborn infants. Unpasteurized milk and cheeses can promote the growth of Listeria bacteria. Listeria monocytogenes can also cause serious infection in an infant and pregnant woman and can be transmitted to her infant in utero or after birth. The infection has the potential of seriously harming or even causing the death of a preterm infant, an infant of low or very low birth weight, or an infant with a congenital defect of the immune system. The presence of this pathogen can sometimes be determined by the symptoms that appear as a gastrointestinal illness in the mother. The mother can also acquire infection from ingesting food that contains other animal products such as hot dogs, delicatessen meats, and cheese.

Cow’s milk allergy (CMA) is an immunologically mediated adverse reaction, rarely fatal, to one or more cow’s milk proteins. 2.2–3.5% of the global infant population are allergic to cow’s milk.

Flavored milk in U.S. schools

Milk must be offered at every meal if a United States school district wishes to get reimbursement from the federal government. A quarter of the largest school districts in the U.S. offer rice or soy milk and almost 17% of all U.S. school districts offer lactose-free milk. Of the milk served in U.S. school cafeterias, 71% is flavored, causing some school districts to propose a ban because flavored milk has added sugars. (Though some flavored milk products use artificial sweeteners instead.) The Boulder, Colorado, school district banned flavored milk in 2009. To keep the consumption up, the school installed a milk dispenser.

Evolution of lactation

The mammary gland is thought to have derived from apocrine skin glands. It has been suggested that the original function of lactation (milk production) was keeping eggs moist. Much of the argument is based on monotremes (egg-laying mammals). The original adaptive significance of milk secretions may have been nutrition or immunological protection. This secretion gradually became more copious and accrued nutritional complexity over evolutionary time.

Tritylodontid cynodonts seem to have displayed lactation, based on their dental replacement patterns.

Bovine growth hormone supplementation

Since November 1993, recombinant bovine somatotropin (rbST), also called rBGH, has been sold to dairy farmers with FDA approval. Cows produce bovine growth hormone naturally, but some producers administer an additional recombinant version of BGH which is produced through genetically engineered E. coli to increase milk production. Bovine growth hormone also stimulates liver production of insulin-like growth factor 1 (IGF1). The U.S. Food and Drug Administration, the National Institutes of Health and the World Health Organization have reported that both of these compounds are safe for human consumption at the amounts present.

Milk from cows given rBST may be sold in the United States, and the FDA stated that no significant difference has been shown between milk derived from rBST-treated and that from non-rBST-treated cows. Milk that advertises that it comes from cows not treated with rBST, is required to state this finding on its label.

Cows receiving rBGH supplements may more frequently contract an udder infection known as mastitis. Problems with mastitis have led to Canada, Australia, New Zealand, and Japan banning milk from rBST treated cows. Mastitis, among other diseases, may be responsible for the fact that levels of white blood cells in milk vary naturally.

rBGH is also banned in the European Union, for reasons of animal welfare.

Criticism

Vegans and some other vegetarians do not consume milk for reasons mostly related to animal rights and environmental concerns. They may object to features of dairy farming including the necessity of keeping dairy cows pregnant, the killing of almost all the male offspring of dairy cows (either by disposal soon after birth, for veal production, or for beef), the routine separation of mother and calf soon after birth, other perceived inhumane treatment of dairy cattle, and culling of cows after their productive lives.

Other people who do not drink milk are convinced that milk is not necessary for good health or that it may cause adverse health effects. Several studies have indicated that milk consumption does not result in stronger bones. Other studies have found that milk intake increases the risk of acquiring acne.

Related is the criticism of governments’ promotion of milk and cheese consumption, in particular the U.S. First, the science remains unsettled as to the effect(s) of calcium-intake on human iron-processing. In addition, the U.S. government, particularly through school food-programs, motivates the (daily) consumption of milk and, especially growing since the 1970s, cheese. According to Daniel Imhoff and Christina Badracco (2019), since the 1970s the «subsidy programs have steadily supported an oversupply of milk. Although milk consumption has decreased over the same time span […] Cheese is now the top source of saturated fat in the US diet, contributing almost 9 percent». All United States schools that are a part of the federally funded National School Lunch Act are required by the federal government to provide milk for all students. The Office of Dietary Supplements recommends that healthy adults between ages 19 and 50 get about 1,000 mg of calcium per day.

It is often argued that it is unnatural for humans to drink milk from cows (or other animals) because mammals normally do not drink milk beyond the weaning period, nor do they drink milk from another species.

Milk production is also resource intensive. On a global weighted average, for the production of a given volume of milk, a thousand times as much water has to be used.

Varieties and brands

Glass milk bottle used for home delivery service in the UK

Milk products are sold in a number of varieties based on types/degrees of:

• additives (e.g. vitamins, flavorings)
• age (e.g. cheddar, old cheddar)
• coagulation (e.g. cottage cheese)
• farming method (e.g. organic, grass-fed, hay milk)
• fat content (e.g. half and half, 3% fat milk, 2% milk, 1% milk, skim milk)
• fermentation (e.g. buttermilk)
• flavoring (e.g. chocolate and strawberry)
• homogenization (e.g. cream top)
• packaging (e.g. bottle, carton, bag)
• pasteurization (e.g. raw milk, pasteurized milk)
• reduction or elimination of lactose
• species (e.g. cow, goat, sheep)
• sweetening (e.g., chocolate and strawberry milk)
• water content (e.g. dry milk powder, condensed milk, ultrafiltered milk)

Milk preserved by the UHT process does not need to be refrigerated before opening and has a much longer shelf life (six months) than milk in ordinary packaging. It is typically sold unrefrigerated in the UK, U.S., Europe, Latin America, and Australia.

Reduction or elimination of lactose

Lactose-free milk can be produced by passing milk over lactase enzyme bound to an inert carrier. Once the molecule is cleaved, there are no lactose ill effects. Forms are available with reduced amounts of lactose (typically 30% of normal), and alternatively with nearly 0%. The only noticeable difference from regular milk is a slightly sweeter taste due to the generation of glucose by lactose cleavage. It does not, however, contain more glucose, and is nutritionally identical to regular milk.

Finland, where approximately 17% of the Finnish-speaking population has hypolactasia, has had «HYLA» (acronym for hydrolyzed lactose) products available for many years. Lactose of low-lactose level cow’s milk products, ranging from ice cream to cheese, is enzymatically hydrolyzed into glucose and galactose. The ultra-pasteurization process, combined with aseptic packaging, ensures a long shelf life. In 2001, Valio launched a lactose-free milk drink that is not sweet like HYLA milk but has the fresh taste of ordinary milk. Valio patented the chromatographic separation method to remove lactose. Valio also markets these products in Sweden, Estonia, Belgium, and the United States, where the company says ultrafiltration is used.

In the UK, where an estimated 4.7% of the population are affected by lactose intolerance,Lactofree produces milk, cheese, and yogurt products that contain only 0.03% lactose.

To aid digestion in those with lactose intolerance, milk with added bacterial cultures such as Lactobacillus acidophilus («acidophilus milk») and bifidobacteria («») is available in some areas. Another milk with Lactococcus lactis bacteria cultures («cultured buttermilk «) often is used in cooking to replace the traditional use of naturally soured milk, which has become rare due to the ubiquity of pasteurization, which also kills the naturally occurring Lactococcus bacteria.

Lactose-free and lactose-reduced milk can also be produced via ultra filtration, which removes smaller molecules such as lactose and water while leaving calcium and proteins behind. Milk produced via these methods has a lower sugar content than regular milk.

Additives and flavoring

In areas where the cattle (and often the people) live indoors, commercially sold milk commonly has vitamin D added to it to make up for lack of exposure to UVB radiation.

Reduced-fat milks often have added vitamin A palmitate to compensate for the loss of the vitamin during fat removal; in the United States this results in reduced fat milks having a higher vitamin A content than whole milk.

Milk often has flavoring added to it for better taste or as a means of improving sales. Chocolate milk has been sold for many years and has been followed more recently by strawberry milk and others. Some nutritionists have criticized flavored milk for adding sugar, usually in the form of high-fructose corn syrup, to the diets of children who are already commonly obese in the U.S.

Distribution

Returning reusable glass milk bottles, used for home delivery service in the UKA glass bottle of non-homogenized, organic, local milk from the US state of California. American milk bottles are generally rectangular in shape.A rectangular milk jug design used by Costco and Sam’s Club stores in the United States which allows for stacking and display of filled containers rather than being shipped to the store in milk crates and manual loading into a freezer display rackA primary school child in England drinking milk out of a glass bottle with a straw

Due to the short shelf life of normal milk, it used to be delivered to households daily in many countries; however, improved refrigeration at home, changing food shopping patterns because of supermarkets, and the higher cost of home delivery mean that daily deliveries by a milkman are no longer available in most countries.

Australia and New Zealand

In Australia and New Zealand, prior to metrication, milk was generally distributed in 1 pint (568 mL) glass bottles. In Australia and Ireland there was a government funded «free milk for school children» program, and milk was distributed at morning recess in 1/3 pint bottles. With the conversion to metric measures, the milk industry was concerned that the replacement of the pint bottles with 500 mL bottles would result in a 13.6% drop in milk consumption; hence, all pint bottles were recalled and replaced by 600 mL bottles. With time, due to the steadily increasing cost of collecting, transporting, storing and cleaning glass bottles, they were replaced by cardboard cartons. A number of designs were used, including a tetrahedron which could be close-packed without waste space, and could not be knocked over accidentally (slogan: «No more crying over spilt milk»). However, the industry eventually settled on a design similar to that used in the United States.

Milk is now available in a variety of sizes in paperboard milk cartons (250 mL, 375 mL, 600 mL, 1 liter and 1.5 liters) and plastic bottles (1, 2 and 3 liters). A significant addition to the marketplace has been «long-life» milk (UHT ), generally available in 1 and 2 liter rectangular cardboard cartons. In urban and suburban areas where there is sufficient demand, home delivery is still available, though in suburban areas this is often 3 times per week rather than daily. Another significant and popular addition to the marketplace has been flavored milks; for example, as mentioned above, Farmers Union Iced Coffee outsells Coca-Cola in South Australia.

India

In rural India, milk is home delivered, daily, by local milkmen carrying bulk quantities in a metal container, usually on a bicycle. In other parts of metropolitan India, milk is usually bought or delivered in plastic bags or cartons via shops or supermarkets.

The current milk chain flow in India is from milk producer to milk collection agent. Then it is transported to a milk chilling center and bulk transported to the processing plant, then to the sales agent and finally to the consumer.

A 2011 survey by the Food Safety and Standards Authority of India found that nearly 70% of samples had not conformed to the standards set for milk. The study found that due to lack of hygiene and sanitation in milk handling and packaging, detergents (used during cleaning operations) were not washed properly and found their way into the milk. About 8% of samples in the survey were found to have detergents, which are hazardous to health.

Pakistan

In Pakistan, milk is supplied in jugs. Milk has been a staple food, especially among the pastoral tribes in this country.

United Kingdom

Since the late 1990s, milk-buying patterns have changed drastically in the UK. The classic milkman, who travels his local milk round (route) using a milk float (often battery powered) during the early hours and delivers milk in 1-pint glass bottles with aluminum foil tops directly to households, has almost disappeared. Two of the main reasons for the decline of UK home deliveries by milkmen are household refrigerators (which lessen the need for daily milk deliveries) and private car usage (which has increased supermarket shopping). Another factor is that it is cheaper to purchase milk from a supermarket than from home delivery. In 1996, more than 2.5 billion liters of milk were still being delivered by milkmen, but by 2006 only 637 million liters (13% of milk consumed) was delivered by some 9,500 milkmen. By 2010, the estimated number of milkmen had dropped to 6,000. Assuming that delivery per milkman is the same as it was in 2006, this means milkmen deliveries now only account for 6–7% of all milk consumed by UK households (6.7 billion liters in 2008/2009).

Almost 95% of all milk in the UK is thus sold in shops today, most of it in plastic bottles of various sizes, but some also in milk cartons. Milk is hardly ever sold in glass bottles in UK shops.

United States

In the United States, glass milk bottles have been replaced mostly with milk cartons and plastic jugs. Gallons of milk are almost always sold in jugs, while half gallons and quarts may be found in both paper cartons and plastic jugs, and smaller sizes are almost always in cartons.

The «half pint» (237 mL, ⁄12imp pt) milk carton is the traditional unit as a component of school lunches, though some companies have replaced that unit size with a plastic bottle, which is also available at retail in 6- and 12-pack size.

Packaging

Glass milk bottles are now rare. Most people purchase milk in bags, plastic bottles, or plastic-coated paper cartons. Ultraviolet (UV) light from fluorescent lighting can alter the flavor of milk, so many companies that once distributed milk in transparent or highly translucent containers are now using thicker materials that block the UV light. Milk comes in a variety of containers with local variants:

Argentina

Commonly sold in 1-liter bags and cardboard boxes. The bag is then placed in a plastic jug and the corner cut off before the milk is poured.

Australia and New Zealand

Distributed in a variety of sizes, most commonly in aseptic cartons for up to 1.5 liters, and plastic screw-top bottles beyond that with the following volumes; 1.1 L, 2 L, and 3 L. 1-liter milk bags are starting to appear in supermarkets, but have not yet proved popular. Most UHT-milk is packed in 1 or 2 liter paper containers with a sealed plastic spout.

Brazil

Used to be sold in cooled 1-liter bags, just like in South Africa. Today the most common form is 1-liter aseptic cartons containing UHT skimmed, semi-skimmed or whole milk, although the plastic bags are still in use for pasteurized milk. Higher grades of pasteurized milk can be found in cartons or plastic bottles. Sizes other than 1-liter are rare.

Four liter bagged milk in Quebec, Canada

Canada

1.33 liter plastic bags (sold as 4 liters in 3 bags) are widely available in some areas (especially the Maritimes, Ontario and Quebec ), although the 4 liter plastic jug has supplanted them in western Canada. Other common packaging sizes are 2 liter, 1 liter, 500 mL, and 250 mL cartons, as well as 4 liter, 1 liter, 250 mL aseptic cartons and 500 mL plastic jugs.

Chile

Distributed most commonly in aseptic cartons for up to 1 liter, but smaller, snack-sized cartons are also popular. The most common flavors, besides the natural presentation, are chocolate, strawberry and vanilla.

China

Sweetened milk is a drink popular with students of all ages and is often sold in small plastic bags complete with straw. Adults not wishing to drink at a banquet often drink milk served from cartons or milk tea.

Colombia

Sells milk in 1-liter plastic bags.

Croatia, Bosnia and Herzegovina, Serbia, Montenegro

UHT milk (trajno mlijeko/trajno mleko/трајно млеко) is sold in 500 mL and 1 L (sometimes also 200 mL) aseptic cartons. Non-UHT pasteurized milk (svježe mlijeko/sveže mleko/свеже млеко) is most commonly sold in 1 L and 1.5 L PET bottles, though in Serbia one can still find milk in plastic bags.

Estonia

Commonly sold in 1 L bags or 0.33 L, 0.5 L, 1 L or 1.5 L cartons.

Parts of Europe

Sizes of 500 mL, 1 liter (the most common), 1.5 liters, 2 liters and 3 liters are commonplace.

Finland

Commonly sold in 1 L or 1.5 L cartons, in some places also in 2 dl and 5 dl cartons.

Germany

Commonly sold in 1-liter cartons. Sale in 1-liter plastic bags (common in the 1980s) is now rare.

Hong Kong

Milk is sold in glass bottles (220 mL), cartons (236 mL and 1 L), plastic jugs (2 liters) and aseptic cartons (250 mL).

India

Commonly sold in 500 mL plastic bags and in bottles in some parts like in the West. It is still customary to serve the milk boiled, despite pasteurization. Milk is often buffalo milk. Flavored milk is sold in most convenience stores in waxed cardboard containers. Convenience stores also sell many varieties of milk (such as flavored and ultra-pasteurized) in various sizes, usually in aseptic cartons.

Indonesia

Usually sold in 1-liter cartons, but smaller, snack-sized cartons are available.

Israel

A plastic bag of milk in Israel

Non-UHT milk is most commonly sold in 1-liter waxed cardboard boxes and 1-liter plastic bags. It may also be found in 1.5 L and 2 L waxed cardboard boxes, 2 L plastic jugs and 1 L plastic bottles. UHT milk is available in 1-liter (and less commonly also in 0.5 L) carton «bricks».

Japan

Commonly sold in 1-liter waxed paperboard cartons. In most city centers there is also home delivery of milk in glass jugs. As seen in China, sweetened and flavored milk drinks are commonly seen in vending machines.

Kenya

Milk in Kenya is mostly sold in plastic-coated aseptic paper cartons supplied in 300 mL, 500 mL or 1 liter volumes. In rural areas, milk is stored in plastic bottles or gourds. The standard unit of measuring milk quantity in Kenya is a liter.

Pakistan

Milk is supplied in 500 mL plastic bags and carried in jugs from rural to cities for selling

Philippines

Milk is supplied in 1000 mL plastic bottles and delivered from factories to cities for selling.

Poland

UHT milk is mostly sold in aseptic cartons (500 mL, 1 L, 2 L), and non-UHT in 1 L plastic bags or plastic bottles. Milk, UHT is commonly boiled, despite being pasteurized.

South Africa

Commonly sold in 1-liter bags. The bag is then placed in a plastic jug and the corner cut off before the milk is poured.

South Korea

Sold in cartons (180 mL, 200 mL, 500 mL 900 mL, 1 L, 1.8 L, 2.3 L), plastic jugs (1 L and 1.8 L), aseptic cartons (180 mL and 200 mL) and plastic bags (1 L).

Sweden

The milk section in a Swedish grocery store

Commonly sold in 0.3 L, 1 L or 1.5 L cartons and sometimes as plastic or glass milk bottles.

Turkey

Commonly sold in 500 mL or 1L cartons or special plastic bottles. UHT milk is more popular. Milkmen also serve in smaller towns and villages.

United Kingdom

Most stores stock imperial sizes: 1 pint (568 mL), 2 pints (1.136 L), 4 pints (2.273 L), 6 pints (3.408 L) or a combination including both metric and imperial sizes. Glass milk bottles delivered to the doorstep by the milkman are typically pint-sized and are returned empty by the householder for repeated reuse. Milk is sold at supermarkets in either aseptic cartons or HDPE bottles. Supermarkets have also now begun to introduce milk in bags, to be poured from a proprietary jug and nozzle.

United States

Commonly sold in gallon (3.78 L), half-gallon (1.89 L) and quart (0.94 L) containers of natural-colored HDPE resin, or, for sizes less than one gallon, cartons of waxed paperboard. Bottles made of opaque PET are also becoming commonplace for smaller, particularly metric, sizes such as one liter. The U.S. single-serving size is usually the half-pint (about 240 mL). Less frequently, dairies deliver milk directly to consumers, from coolers filled with glass bottles which are typically half-gallon sized and returned for reuse. Some convenience store chains in the United States (such as Kwik Trip in the Midwest ) sell milk in half-gallon bags, while another rectangular cube gallon container design used for easy stacking in shipping and displaying is used by warehouse clubs such as Costco and Sam’s Club, along with some Wal-Mart stores.

Uruguay

Pasteurized milk is commonly sold in 1-liter bags and ultra-pasteurized milk is sold in cardboard boxes called Tetra Briks. Non-pasteurized milk is forbidden. Until the 1960s no treatment was applied; milk was sold in bottles. As of 2017, plastic jugs used for pouring the bags, or «sachets», are in common use.

Practically everywhere, condensed milk and evaporated milk are distributed in metal cans, 250 and 125 mL paper containers and 100 and 200 mL squeeze tubes, and powdered milk (skim and whole) is distributed in boxes or bags.

Spoilage and fermented milk products

Yakult, a probiotic milk-like product made by fermenting a mixture of skimmed milk with a special strain of the bacterium Lactobacillus casei ShirotaGourd used by Kalenjins to prepare a local version of fermented milk called mursik

When raw milk is left standing for a while, it turns «sour «. This is the result of fermentation, where lactic acid bacteria ferment the lactose in the milk into lactic acid. Prolonged fermentation may render the milk unpleasant to consume. This fermentation process is exploited by the introduction of bacterial cultures (e.g. Lactobacilli sp., Streptococcus sp., Leuconostoc sp., etc.) to produce a variety of fermented milk products. The reduced pH from lactic acid accumulation denatures proteins and causes the milk to undergo a variety of different transformations in appearance and texture, ranging from an aggregate to smooth consistency. Some of these products include sour cream, yogurt, cheese, buttermilk, viili, kefir, and kumis. See Dairy product for more information.

Pasteurization of cow’s milk initially destroys any potential pathogens and increases the shelf life, but eventually results in spoilage that makes it unsuitable for consumption. This causes it to assume an unpleasant odor, and the milk is deemed non-consumable due to unpleasant taste and an increased risk of food poisoning. In raw milk, the presence of lactic acid-producing bacteria, under suitable conditions, ferments the lactose present to lactic acid. The increasing acidity in turn prevents the growth of other organisms, or slows their growth significantly. During pasteurization, however, these lactic acid bacteria are mostly destroyed.

In order to prevent spoilage, milk can be kept refrigerated and stored between 1 and 4 °C (34 and 39 °F) in bulk tanks. Most milk is pasteurized by heating briefly and then refrigerated to allow transport from factory farms to local markets. The spoilage of milk can be forestalled by using ultra-high temperature (UHT ) treatment. Milk so treated can be stored unrefrigerated for several months until opened but has a characteristic «cooked» taste. Condensed milk, made by removing most of the water, can be stored in cans for many years, unrefrigerated, as can evaporated milk. The most durable form of milk is powdered milk, which is produced from milk by removing almost all water. The moisture content is usually less than 5% in both drum- and spray-dried powdered milk.

Freezing of milk can cause fat globule aggregation upon thawing, resulting in milky layers and butterfat lumps. These can be dispersed again by warming and stirring the milk. It can change the taste by destruction of milk-fat globule membranes, releasing oxidized flavors.

Use in other food products

is used in a variety of espresso -based coffee beverages.

Milk is used to make yogurt, cheese, ice milk, pudding, hot chocolate and french toast, among many other products. Milk is often added to dry breakfast cereal, porridge and granola. Milk is mixed with ice cream and flavored syrups in a blender to make milkshakes. Milk is often served in coffee and tea. Frothy steamed milk is used to prepare espresso -based drinks such as cafe latte.

In language and culture

Hindu Abhisheka ritual in Agara, Bangalore Rural District, Karnataka

The importance of milk in human culture is attested to by the numerous expressions embedded in our languages, for example, «the milk of human kindness», the expression «there’s no use crying over spilt milk» (which means don’t «be unhappy about what cannot be undone»), «don’t milk the ram» (this means «to do or attempt something futile») and «Why buy a cow when you can get milk for free?» (which means «why pay for something that you can get for free otherwise»).

In Greek mythology, the Milky Way was formed after the trickster god Hermes suckled the infant Heracles at the breast of Hera, the queen of the gods, while she was asleep. When Hera awoke, she tore Heracles away from her breast and splattered her breast milk across the heavens. In another version of the story, Athena, the patron goddess of heroes, tricked Hera into suckling Heracles voluntarily, but he bit her nipple so hard that she flung him away, spraying milk everywhere.

In many African and Asian countries, butter is traditionally made from fermented milk rather than cream. It can take several hours of churning to produce workable butter grains from fermented milk.

Holy books have also mentioned milk. The Bible contains references to the «Land of Milk and Honey.» In the Qur’an, there is a request to wonder on milk as follows: «And surely in the livestock there is a lesson for you, We give you to drink of that which is in their bellies from the midst of digested food and blood, pure milk palatable for the drinkers» (16-The Honeybee, 66). The Ramadan fast is traditionally broken with a glass of milk and dates.

Abhisheka is conducted by Hindu and Jain priests, by pouring libations on the idol of a deity being worshipped, amidst the chanting of mantras. Usually offerings such as milk, yogurt, ghee, honey may be poured among other offerings depending on the type of abhishekam being performed.

A milksop is an «effeminate spiritless man,» an expression which is attested to in the late 14th century.Milk toast is a dish consisting of milk and toast. Its soft blandness served as inspiration for the name of the timid and ineffectual comic strip character Caspar Milquetoast, drawn by H. T. Webster from 1924 to 1952. Thus, the term «milquetoast» entered the language as the label for a timid, shrinking, apologetic person. Milk toast also appeared in Disney’s Follow Me Boys as an undesirable breakfast for the aging main character Lem Siddons.

To «milk» someone, in the vernacular of many English-speaking countries, is to take advantage of the person, by analogy to the way a farmer «milks» a cow and takes its milk. The word «milk» has had many slang meanings over time. In the 19th century, milk was used to describe a cheap and very poisonous alcoholic drink made from methylated spirits (methanol) mixed with water. The word was also used to mean defraud, to be idle, to intercept telegrams addressed to someone else, and a weakling or «milksop.» In the mid-1930s, the word was used in Australia to refer to siphoning gas from a car.

Non-culinary uses

Besides serving as a beverage or source of food, milk has been described as used by farmers and gardeners as an organic fungicide and fertilizer, however, its effectiveness is debated. Diluted milk solutions have been demonstrated to provide an effective method of preventing powdery mildew on grape vines, while showing it is unlikely to harm the plant.

Milk paint is a nontoxic water-based paint. It can be made from milk and lime, generally with pigments added for color. In other recipes, borax is mixed with milk’s casein protein in order to activate the casein and as a preservative.

A woman in a milk bath.

Milk has been used for centuries as a hair and skin treatment. Hairstylist Richard Marin states that some women rinse their hair with milk to add a shiny appearance to their hair. Cosmetic chemist Ginger King states that milk can «help exfoliate and remove debris [from skin] and make hair softer. Hairstylist Danny Jelaca states that milk’s keratin proteins may «add weight to the hair». Some commercial hair products contain milk.

A milk bath is a bath taken in milk rather than just water. Often additives such as oatmeal, honey, and scents such as rose, daisies and essential oils are mixed in. Milk baths use lactic acid, an alpha hydroxy acid, to dissolve the proteins which hold together dead skin cells.

See also

• A2 milk
• Babcock test (determines the butterfat content of milk)
• Blocked milk duct
• Fermented milk products
• Health mark
• Human breast milk
• Lactation
• List of dairy products
• List of national drinks
• Milk line
• Milk paint
• Milk substitute
• Milky Way
• Operation Flood
• Raw milk
• World Milk Day

Food portalDrink portal

Notes

References

Further reading

• Dillon, John J. Seven decades of milk,: A history of New York’s dairy industry (1941)
• Innis, Harold A. The dairy industry in Canada (1937) online
• Kardashian, Kirk. Milk Money: Cash, Cows, and the Death of the American Dairy Farm (2012)
• Kurlansky, Mark. Milk: A 10,000-Year History (2019); also published as Milk!: A 10,000-Year Food Fracas (2019)
• McGee, Harold (2004). On Food and Cooking (2nd ed.). New York: Scribner. ISBN 978-0-684-80001-1.
• Prasad, Rajendra (2017). «Historical Aspects of Milk Consumption in South, Southeast, and East Asia» (PDF). Asian Agricultural History. 21(4): 287–307.
• Scherbaum, Veronika; Srour, M. Leila (2018). «Milk products in the dietary management of childhood undernutrition – a historical review» (PDF). Nutrition Research Reviews. 31(1): 71–84. doi :10.1017/s0954422417000208. PMID 29113618. S2CID 910669.
• Smith-Howard, Kendra. Pure and Modern Milk: An Environmental History Since 1900. (Oxford University Press; 2013).
• Valenze, Deborah. Milk: A Local and Global History (Yale University Press, 2011) 368 pp.
• Wiley, Andrea. Re-imagining Milk: Cultural and Biological Perspectives (Routledge 2010) (Series for Creative Teaching and Learning in Anthropology)

External links

• Milk at Curlie

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This article is about the fluid produced by the mammary glands of mammals. For the milk-like beverages derived from plants, see Plant milk. For other uses of the word, see Milk (disambiguation).

Milk is a white liquid food produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals (including breastfed human infants) before they are able to digest solid food.^[1] Immune factors and immune-modulating components in milk contribute to milk immunity. Early-lactation milk, which is called colostrum, contains antibodies that strengthen the immune system, and thus reduces the risk of many diseases. Milk contains many nutrients, including protein and lactose.^[2]

As an agricultural product, dairy milk is collected from farm animals. In 2011, dairy farms produced around 730 million tonnes (800 million short tons) of milk^[3] from 260 million dairy cows.^[4] India is the world’s largest producer of milk and the leading exporter of skimmed milk powder, but it exports few other milk products.^[5][6] Because there is an ever-increasing demand for dairy products within India, it could eventually become a net importer of dairy products.^[7] New Zealand, Germany and the Netherlands are the largest exporters of milk products.^[8] The US CDC recommends that children over the age of 12 months should have two servings of dairy milk products a day.^[9]

More than six billion people worldwide consume milk and milk products, and between 750 and 900 million people live in dairy-farming households.^[10]

Etymology and terminology

The term milk comes from «Old English meoluc (West Saxon), milc (Anglian), from Proto-Germanic *meluks «milk» (source also of Old Norse mjolk, Old Frisian melok, Old Saxon miluk, Dutch melk, Old High German miluh, German Milch, Gothic miluks)».^[11]

In food use, from 1961, the term milk has been defined under Codex Alimentarius standards as: «the normal mammary secretion of milking animals obtained from one or more milkings without either addition to it or extraction from it, intended for consumption as liquid milk or for further processing.»^[12] The term dairy relates to animal milk and animal milk production.

Types of consumption

There are two distinct categories of milk consumption: all infant mammals drink milk directly from their mothers’ bodies, and it is their primary source of nutrition; and humans obtain milk from other mammals for consumption by humans of all ages, as one component of a varied diet.

Nutrition for infant mammals

In almost all mammals, milk is fed to infants through breastfeeding, either directly or by expressing the milk to be stored and consumed later. The early milk from mammals is called colostrum. Colostrum contains antibodies that provide protection to the newborn baby as well as nutrients and growth factors.^[13] The makeup of the colostrum and the period of secretion varies from species to species.^[14]

For humans, the World Health Organization recommends exclusive breastfeeding for six months and breastfeeding in addition to other food for up to two years of age or more.^[15] In some cultures it is common to breastfeed children for three to five years, and the period may be longer.^[16]

Fresh goats’ milk is sometimes substituted for breast milk, which introduces the risk of the child developing electrolyte imbalances, metabolic acidosis, megaloblastic anemia, and a host of allergic reactions.^[17]

Food product for humans

In many cultures, especially in the West, humans continue to consume milk beyond infancy, using the milk of other mammals (especially cattle, goats and sheep) as a food product. Initially, the ability to digest milk was limited to children as adults did not produce lactase, an enzyme necessary for digesting the lactose in milk. People therefore converted milk to curd, cheese, and other products to reduce the levels of lactose. Thousands of years ago, a chance mutation spread in human populations in northwestern Europe that enabled the production of lactase in adulthood. This mutation allowed milk to be used as a new source of nutrition which could sustain populations when other food sources failed.^[18] Milk is processed into a variety of products such as cream, butter, yogurt, kefir, ice cream, and cheese. Modern industrial processes use milk to produce casein, whey protein, lactose, condensed milk, powdered milk, and many other food-additives and industrial products.

Whole milk, butter, and cream have high levels of saturated fat.^[19][20] The sugar lactose is found only in milk, and possibly in forsythia flowers and a few tropical shrubs.^[21] Lactase, the enzyme needed to digest lactose, reaches its highest levels in the human small intestine immediately after birth, and then begins a slow decline unless milk is consumed regularly.^[22] Those groups who continue to tolerate milk have often exercised great creativity in using the milk of domesticated ungulates, not only cattle, but also sheep, goats, yaks, water buffalo, horses, reindeer and camels. India is the largest producer and consumer of cattle milk and buffalo milk in the world.^[23]

Per capita consumption of milk and milk products in selected countries in 2011^[24]

Country	Milk (liters)	Cheese (kg)	Butter (kg)
Ireland	135.6	6.7	2.4
Finland	127.0	22.5	4.1
United Kingdom	105.9	10.9	3.0
Australia	105.3	11.7	4.0
Sweden	90.1	19.1	1.7
Canada	78.4	12.3	2.5
United States	75.8	15.1	2.8
Europe	62.8	17.1	3.6
Brazil	55.7	3.6	0.4
France	55.5	26.3	7.5
Italy	54.2	21.8	2.3
Germany	51.8	22.9	5.9
Greece	49.1	23.4	0.7
Netherlands	47.5	19.4	3.3
India	39.5	—	3.5
China	9.1	—	0.1

History

Humans first learned to consume the milk of other mammals regularly following the domestication of animals during the Neolithic Revolution or the development of agriculture. This development occurred independently in several global locations from as early as 9000–7000 BC in Mesopotamia^[25] to 3500–3000 BC in the Americas.^[26] People first domesticated the most important dairy animals – cattle, sheep and goats – in Southwest Asia, although domestic cattle had been independently derived from wild aurochs populations several times since.^[27] Initially animals were kept for meat, and archaeologist Andrew Sherratt has suggested that dairying, along with the exploitation of domestic animals for hair and labor, began much later in a separate secondary products revolution in the fourth millennium BC.^[28] Sherratt’s model is not supported by recent findings, based on the analysis of lipid residue in prehistoric pottery, that shows that dairying was practiced in the early phases of agriculture in Southwest Asia, by at least the seventh millennium BC.^[29][30]

From Southwest Asia domestic dairy animals spread to Europe (beginning around 7000 BC but did not reach Britain and Scandinavia until after 4000 BC),^[31] and South Asia (7000–5500 BC).^[32] The first farmers in central Europe^[33] and Britain^[34] milked their animals. Pastoral and pastoral nomadic economies, which rely predominantly or exclusively on domestic animals and their products rather than crop farming, were developed as European farmers moved into the Pontic–Caspian steppe in the fourth millennium BC, and subsequently spread across much of the Eurasian steppe.^[35] Sheep and goats were introduced to Africa from Southwest Asia, but African cattle may have been independently domesticated around 7000–6000 BC.^[36] Camels, domesticated in central Arabia in the fourth millennium BC, have also been used as dairy animals in North Africa and the Arabian Peninsula.^[37] The earliest Egyptian records of burn treatments describe burn dressings using milk from mothers of male babies.^[38] In the rest of the world (i.e., East and Southeast Asia, the Americas and Australia), milk and dairy products were historically not a large part of the diet, either because they remained populated by hunter-gatherers who did not keep animals or the local agricultural economies did not include domesticated dairy species. Milk consumption became common in these regions comparatively recently, as a consequence of European colonialism and political domination over much of the world in the last 500 years.

In the Middle Ages, milk was called the «virtuous white liquor» because alcoholic beverages were safer to consume than the water generally available.^[39] Incorrectly thought to be blood diverted from the womb to the breast, it was also known as «white blood», and treated like blood for religious dietary purposes and in humoral theory.^[40]

James Rosier’s record of the 1605 voyage made by George Weymouth to New England reported that the Wabanaki people Weymouth captured in Maine milked «Rain-Deere and Fallo-Deere.» But Journalist Avery Yale Kamila and food historians said Rosier «misinterpreted the evidence.» Historians report the Wabanaki did not domesticate deer.^[41][42] The tribes of the northern woodlands have historically been making nut milk.^[43] Cows were imported to New England in 1624.^[44]

Industrialization

The growth in urban population, coupled with the expansion of the railway network in the mid-19th century, brought about a revolution in milk production and supply. Individual railway firms began transporting milk from rural areas to London from the 1840s and 1850s. Possibly the first such instance was in 1846, when St Thomas’s Hospital in Southwark contracted with milk suppliers outside London to ship milk by rail.^[45] The Great Western Railway was an early and enthusiastic adopter, and began to transport milk into London from Maidenhead in 1860, despite much criticism. By 1900, the company was transporting over 25 million imperial gallons (110 million litres; 30 million US gallons) annually.^[46] The milk trade grew slowly through the 1860s, but went through a period of extensive, structural change in the 1870s and 1880s.

Urban demand began to grow, as consumer purchasing power increased and milk became regarded as a required daily commodity. Over the last three decades of the 19th century, demand for milk in most parts of the country doubled or, in some cases, tripled. Legislation in 1875 made the adulteration of milk illegal – This combined with a marketing campaign to change the image of milk. The proportion of rural imports by rail as a percentage of total milk consumption in London grew from under 5% in the 1860s to over 96% by the early 20th century. By that point, the supply system for milk was the most highly organized and integrated of any food product.^[45] Milk was analyzed for infection with tuberculosis. In 1907 180 samples were tested in Birmingham and 13.3% were found to be infected.^[47]

The first glass bottle packaging for milk was used in the 1870s. The first company to do so may have been the New York Dairy Company in 1877. The Express Dairy Company in England began glass bottle production in 1880. In 1884, Hervey Thatcher, an American inventor from New York, invented a glass milk bottle, called «Thatcher’s Common Sense Milk Jar,» which was sealed with a waxed paper disk.^[48] In 1932, plastic-coated paper milk cartons were introduced commercially.^[48]

In 1863, French chemist and biologist Louis Pasteur invented pasteurization, a method of killing harmful bacteria in beverages and food products.^[48] He developed this method while on summer vacation in Arbois, to remedy the frequent acidity of the local wines.^[49] He found out experimentally that it is sufficient to heat a young wine to only about 50–60 °C (122–140 °F) for a brief time to kill the microbes, and that the wine could be nevertheless properly aged without sacrificing the final quality.^[49] In honor of Pasteur, the process became known as «pasteurization». Pasteurization was originally used as a way of preventing wine and beer from souring.^[50] Commercial pasteurizing equipment was produced in Germany in the 1880s, and producers adopted the process in Copenhagen and Stockholm by 1885.^[51][52]

Sources

The females of all mammal species can, by definition, produce milk, but cow’s milk dominates commercial production. In 2011, FAO estimates 85% of all milk worldwide was produced from cows.^[53] Human milk is not produced or distributed industrially or commercially; however, human milk banks collect donated human breastmilk and redistribute it to infants who may benefit from human milk for various reasons (premature neonates, babies with allergies, metabolic diseases, etc.) but who cannot breastfeed.^[54]

In the Western world, cow’s milk is produced on an industrial scale and is, by far, the most commonly consumed form of milk. Commercial dairy farming using automated milking equipment produces the vast majority of milk in developed countries. Dairy cattle, such as the Holstein, have been bred selectively for increased milk production. About 90% of the dairy cows in the United States and 85% in Great Britain are Holsteins.^[22] Other dairy cows in the United States include Ayrshire, Brown Swiss, Guernsey, Jersey and Milking Shorthorn (Dairy Shorthorn).

Other animal-based sources

Aside from cattle, many kinds of livestock provide milk used by humans for dairy products. These animals include water buffalo, goat, sheep, camel, donkey, horse, reindeer and yak. The first four respectively produced about 11%, 2%, 1.4% and 0.2% of all milk worldwide in 2011.^[53]

In Russia and Sweden, small moose dairies also exist.^[55]

According to the US National Bison Association, American bison (also called American buffalo) are not milked commercially;^[56] however, various sources report cows resulting from cross-breeding bison and domestic cattle are good milk producers, and have been used both during the European settlement of North America^[57] and during the development of commercial Beefalo in the 1970s and 1980s.^[58]

Swine are almost never milked, even though their milk is similar to cow’s milk and perfectly suitable for human consumption. The main reasons for this are that milking a sow’s numerous small teats is very cumbersome, and that sows cannot store their milk as cows can.^[59] A few pig farms do sell pig cheese as a novelty item; these cheeses are exceedingly expensive.^[60]

Production worldwide

In 2012, the largest producer of milk and milk products was India, followed by the United States of America, China, Pakistan and Brazil.^[66] All 28 European Union members together produced 153.8 million tonnes (169.5 million short tons) of milk in 2013, the largest by any politico-economic union.^[67]

Increasing affluence in developing countries, as well as increased promotion of milk and milk products, has led to a rise in milk consumption in developing countries in recent years. In turn, the opportunities presented by these growing markets have attracted investments by multinational dairy firms. Nevertheless, in many countries production remains on a small scale and presents significant opportunities for diversification of income sources by small farms.^[68] Local milk collection centers, where milk is collected and chilled prior to being transferred to urban dairies, are a good example of where farmers have been able to work on a cooperative basis, particularly in countries such as India.^[69]

Production yields

FAO reports^[53] Israel dairy farms are the most productive in the world, with a yield of 12,546 kilograms (27,659 lb) milk per cow per year. This survey over 2001 and 2007 was conducted by ICAR (International Committee for Animal Recording)^[70] across 17 developed countries. The survey found that the average herd size in these developed countries increased from 74 to 99 cows per herd between 2001 and 2007. A dairy farm had an average of 19 cows per herd in Norway, and 337 in New Zealand. Annual milk production in the same period increased from 7,726 to 8,550 kg (17,033 to 18,850 lb) per cow in these developed countries. The lowest average production was in New Zealand at 3,974 kg (8,761 lb) per cow. The milk yield per cow depended on production systems, nutrition of the cows, and only to a minor extent different genetic potential of the animals. What the cow ate made the most impact on the production obtained. New Zealand cows with the lowest yield per year grazed all year, in contrast to Israel with the highest yield where the cows ate in barns with an energy-rich mixed diet.

The milk yield per cow in the United States was 9,954 kg (21,945 lb) per year in 2010. In contrast, the milk yields per cow in India and China – the second and third largest producers – were respectively 1,154 kg (2,544 lb) and 2,282 kg (5,031 lb) per year.^[71]

Price

It was reported in 2007 that with increased worldwide prosperity and the competition of bio-fuel production for feed stocks, both the demand for and the price of milk had substantially increased worldwide. Particularly notable was the rapid increase of consumption of milk in China and the rise of the price of milk in the United States above the government subsidized price.^[72] In 2010 the Department of Agriculture predicted farmers would receive an average of $1.35 per US gallon ($0.36/l; $1.62/imp gal) of cow’s milk, which is down 30 cents per US gallon (7.9 ¢/l; 36 ¢/imp gal) from 2007 and below the break-even point for many cattle farmers.^[73]

Composition

Milk is an emulsion or colloid of butterfat globules within a water-based fluid that contains dissolved carbohydrates and protein aggregates with minerals.^[74] Because it is produced as a food source for the young, all of its contents provide benefits for growth. The principal requirements are energy (lipids, lactose, and protein), biosynthesis of non-essential amino acids supplied by proteins (essential amino acids and amino groups), essential fatty acids, vitamins and inorganic elements, and water.^[75]

pH

The pH of cow’s milk ranges from 6.7 to 6.9.^[76] Milk from other bovines and non-bovine mammals varies in composition, but has a similar pH.^[77]

Lipids

Initially milk fat is secreted in the form of a fat globule surrounded by a membrane.^[78] Each fat globule is composed almost entirely of triacylglycerols and is surrounded by a membrane consisting of complex lipids such as phospholipids, along with proteins. These act as emulsifiers which keep the individual globules from coalescing and protect the contents of these globules from various enzymes in the fluid portion of the milk. Although 97–98% of lipids are triacylglycerols, small amounts of di- and monoacylglycerols, free cholesterol and cholesterol esters, free fatty acids, and phospholipids are also present. Unlike protein and carbohydrates, fat composition in milk varies widely due to genetic, lactational, and nutritional factor difference between different species.^[78]

Fat globules vary in size from less than 0.2 to about 15 micrometers in diameter between different species. Diameter may also vary between animals within a species and at different times within a milking of a single animal. In unhomogenized cow’s milk, the fat globules have an average diameter of two to four micrometers and with homogenization, average around 0.4 micrometers.^[78] The fat-soluble vitamins A, D, E, and K along with essential fatty acids such as linoleic and linolenic acid are found within the milk fat portion of the milk.^[22]

Main milk fatty acids, length, share of total^[79]

Fatty acid	length	mol% (rounded)
Butyryl	C4	12
Myristyl	C14	11
Palmityl	C16	24
Oleyl	C18:1	24

Proteins

Normal bovine milk contains 30–35 grams of protein per liter, of which about 80% is arranged in casein micelles. Total proteins in milk represent 3.2% of its composition (nutrition table).

Caseins

The largest structures in the fluid portion of the milk are «casein micelles»: aggregates of several thousand protein molecules with superficial resemblance to a surfactant micelle, bonded with the help of nanometer-scale particles of calcium phosphate. Each casein micelle is roughly spherical and about a tenth of a micrometer across. There are four different types of casein proteins: αs1-, αs2-, β-, and κ-caseins. Most of the casein proteins are bound into the micelles. There are several competing theories regarding the precise structure of the micelles, but they share one important feature: the outermost layer consists of strands of one type of protein, k-casein, reaching out from the body of the micelle into the surrounding fluid. These kappa-casein molecules all have a negative electrical charge and therefore repel each other, keeping the micelles separated under normal conditions and in a stable colloidal suspension in the water-based surrounding fluid.^[22][80]

Milk contains dozens of other types of proteins beside caseins and including enzymes. These other proteins are more water-soluble than caseins and do not form larger structures. Because the proteins remain suspended in whey, remaining when caseins coagulate into curds, they are collectively known as whey proteins. Lactoglobulin is the most common whey protein by a large margin.^[22] The ratio of caseins to whey proteins varies greatly between species; for example, it is 82:18 in cows and around 32:68 in humans.^[81]

Ratio of caseins to whey proteins in milk of nine mammals^[81]

Species	Ratio
Human	29.7:70.3 – 33.7:66.3
Bovine	82:18
Caprine	78:22
Ovine	76:24
Buffalo	82:18
Equine	52:48
Camel	73:27 – 76:24
Yak	82:18
Reindeer	80:20 – 83:17

Salts, minerals, and vitamins

Bovine milk contains a variety of cations and anions traditionally referred to as «minerals» or «milk salts». Calcium, phosphate, magnesium, sodium, potassium, citrate, and chloride are all included and they typically occur at concentrations of 5–40 mM. The milk salts strongly interact with casein, most notably calcium phosphate. It is present in excess and often, much greater excess of solubility of solid calcium phosphate.^[75] In addition to calcium, milk is a good source of many other vitamins. Vitamins A, B6, B12, C, D, K, E, thiamine, niacin, biotin, riboflavin, folates, and pantothenic acid are all present in milk.

Calcium phosphate structure

For many years the most widely accepted theory of the structure of a micelle was that it was composed of spherical casein aggregates, called submicelles, that were held together by calcium phosphate linkages. However, there are two recent models of the casein micelle that refute the distinct micellular structures within the micelle.

The first theory, attributed to de Kruif and Holt, proposes that nanoclusters of calcium phosphate and the phosphopeptide fraction of beta-casein are the centerpiece to micellar structure. Specifically in this view unstructured proteins organize around the calcium phosphate, giving rise to their structure, and thus no specific structure is formed.

Under the second theory, proposed by Horne, the growth of calcium phosphate nanoclusters begins the process of micelle formation, but is limited by binding phosphopeptide loop regions of the caseins. Once bound, protein-protein interactions are formed and polymerization occurs, in which K-casein is used as an end cap to form micelles with trapped calcium phosphate nanoclusters.

Some sources indicate that the trapped calcium phosphate is in the form of Ca₉(PO₄)₆;
whereas others say it is similar to the structure of the mineral brushite, CaHPO₄·2H₂O.^[82]

Sugars and carbohydrates

Milk contains several different carbohydrates, including lactose, glucose, galactose, and other oligosaccharides. The lactose gives milk its sweet taste and contributes approximately 40% of the calories in whole cow’s milk’s. Lactose is a disaccharide composite of two simple sugars, glucose and galactose. Bovine milk averages 4.8% anhydrous lactose, which amounts to about 50% of the total solids of skimmed milk. Levels of lactose are dependent upon the type of milk as other carbohydrates can be present at higher concentrations than lactose in milks.^[75]

Miscellaneous contents

Other components found in raw cow’s milk are living white blood cells, mammary gland cells, various bacteria, vitamin C, and a large number of active enzymes.^[22]

Appearance

Both the fat globules and the smaller casein micelles, which are just large enough to deflect light, contribute to the opaque white color of milk. The fat globules contain some yellow-orange carotene, enough in some breeds (such as Guernsey and Jersey cattle) to impart a golden or «creamy» hue to a glass of milk. The riboflavin in the whey portion of milk has a greenish color, which sometimes can be discerned in skimmed milk or whey products.^[22] Fat-free skimmed milk has only the casein micelles to scatter light, and they tend to scatter shorter-wavelength blue light more than they do red, giving skimmed milk a bluish tint.^[80]

Processing

In most Western countries, centralized dairy facilities process milk and products obtained from milk, such as cream, butter, and cheese. In the US, these dairies usually are local companies, while in the Southern Hemisphere facilities may be run by large multi-national corporations such as Fonterra.

Pasteurization

Pasteurization is used to kill harmful pathogenic bacteria such as M. paratuberculosis and E. coli 0157:H7 by heating the milk for a short time and then immediately cooling it.^[83] Types of pasteurized milk include full cream, reduced fat, skim milk, calcium enriched, flavored, and UHT.^[84] The standard high temperature short time (HTST) process of 72 °C (162 °F) for 15 seconds completely kills pathogenic bacteria in milk,^[85] rendering it safe to drink for up to three weeks if continually refrigerated.^[86] Dairies print best before dates on each container, after which stores remove any unsold milk from their shelves.

A side effect of the heating of pasteurization is that some vitamin and mineral content is lost. Soluble calcium and phosphorus decrease by 5%, thiamin and vitamin B12 by 10%, and vitamin C by 20% or greater (even to complete loss).^[87] Because losses are small in comparison to the large amount of the two B-vitamins present, milk continues to provide significant amounts of thiamin and vitamin B12. The loss of vitamin C is not nutritionally significant in a well-balanced diet, as milk is not an important dietary source of vitamin C.

Filtration

Microfiltration is a process that partially replaces pasteurization and produces milk with fewer microorganisms and longer shelf life without a change in the taste of the milk. In this process, cream is separated from the skimmed milk and is pasteurized in the usual way, but the skimmed milk is forced through ceramic microfilters that trap 99.9% of microorganisms in the milk^[88] (as compared to 99.999% killing of microorganisms in standard HTST pasteurization).^[89] The skimmed milk then is recombined with the pasteurized cream to reconstitute the original milk composition.

Ultrafiltration uses finer filters than microfiltration, which allow lactose and water to pass through while retaining fats, calcium and protein.^[90] As with microfiltration, the fat may be removed before filtration and added back in afterwards.^[91] Ultrafiltered milk is used in cheesemaking, since it has reduced volume for a given protein content, and is sold directly to consumers as a higher protein, lower sugar content, and creamier alternative to regular milk.^[92]

Creaming and homogenization

Upon standing for 12 to 24 hours, fresh milk has a tendency to separate into a high-fat cream layer on top of a larger, low-fat milk layer. The cream often is sold as a separate product with its own uses. Today the separation of the cream from the milk usually is accomplished rapidly in centrifugal cream separators. The fat globules rise to the top of a container of milk because fat is less dense than water.^[22]

The smaller the globules, the more other molecular-level forces prevent this from happening. The cream rises in cow’s milk much more quickly than a simple model would predict: rather than isolated globules, the fat in the milk tends to form into clusters containing about a million globules, held together by a number of minor whey proteins.^[22] These clusters rise faster than individual globules can. The fat globules in milk from goats, sheep, and water buffalo do not form clusters as readily and are smaller to begin with, resulting in a slower separation of cream from these milks.^[22]

Milk often is homogenized, a treatment that prevents a cream layer from separating out of the milk. The milk is pumped at high pressures through very narrow tubes, breaking up the fat globules through turbulence and cavitation.^[93] A greater number of smaller particles possess more total surface area than a smaller number of larger ones, and the original fat globule membranes cannot completely cover them. Casein micelles are attracted to the newly exposed fat surfaces.

Nearly one-third of the micelles in the milk end up participating in this new membrane structure. The casein weighs down the globules and interferes with the clustering that accelerated separation. The exposed fat globules are vulnerable to certain enzymes present in milk, which could break down the fats and produce rancid flavors. To prevent this, the enzymes are inactivated by pasteurizing the milk immediately before or during homogenization.

Homogenized milk tastes blander but feels creamier in the mouth than unhomogenized. It is whiter and more resistant to developing off flavors.^[22] Creamline (or cream-top) milk is unhomogenized. It may or may not have been pasteurized. Milk that has undergone high-pressure homogenization, sometimes labeled as «ultra-homogenized», has a longer shelf life than milk that has undergone ordinary homogenization at lower pressures.^[94]

UHT

Ultra Heat Treatment (UHT) is a type of milk processing where all bacteria are destroyed with high heat to extend its shelf life for up to 6 months, as long as the package is not opened. Milk is firstly homogenized and then is heated to 138 degrees Celsius for 1–3 seconds. The milk is immediately cooled down and packed into a sterile container. As a result of this treatment, all the pathogenic bacteria within the milk are destroyed, unlike when the milk is just pasteurized. The treated milk will keep for up to 6 months if unopened. UHT milk does not need to be refrigerated until the package is opened, which makes it easier to ship and store. However, in this process there is a loss of vitamin B1 and vitamin C, and there is also a slight change in the taste of the milk.^[95]

Nutrition and health

The composition of milk differs widely among species. Factors such as the type of protein; the proportion of protein, fat, and sugar; the levels of various vitamins and minerals; and the size of the butterfat globules, and the strength of the curd are among those that may vary.^[24] For example:

• Human milk contains, on average, 1.1% protein, 4.2% fat, 7.0% lactose (a sugar), and supplies 72 kcal of energy per 100 grams.
• Cow’s milk contains, on average, 3.4% protein, 3.6% fat, and 4.6% lactose, 0.7% minerals^[96] and supplies 66 kcal of energy per 100 grams. See also Nutritional value further on in this article and more complete lists at online sources that list values and differences in categories.^[97]

Donkey and horse milk have the lowest fat content, while the milk of seals and whales may contain more than 50% fat.^[98]

Milk composition analysis, per 100 grams

Constituents	Unit	Cow	Goat	Sheep	Water buffalo
Water	g	87.8	88.9	83.0	81.1
Protein	g	3.2	3.1	5.4	4.5
Fat	g	3.9	3.5	6.0	8.0
—-Saturated fatty acids	g	2.4	2.3	3.8	4.2
—-Monounsaturated fatty acids	g	1.1	0.8	1.5	1.7
—-Polyunsaturated fatty acids	g	0.1	0.1	0.3	0.2
Carbohydrate (i.e. the sugar form of lactose)	g	4.8	4.4	5.1	4.9
Cholesterol	mg	14	10	11	8
Calcium	mg	120	100	170	195
Energy	kcal	66	60	95	110
kJ	275	253	396	463

Cow’s milk: variation by breed

These compositions vary by breed, animal, and point in the lactation period.

Milk fat percentages

Cow breed	Approximate percentage
Jersey	5.2
Zebu	4.7
Brown Swiss	4.0
Holstein-Friesian	3.6

The protein range for these four breeds is 3.3% to 3.9%, while the lactose range is 4.7% to 4.9%.^[22]

Milk fat percentages may be manipulated by dairy farmers’ stock diet formulation strategies. The infection known as mastitis, especially in dairy cattle, can cause fat levels to decline.^[99]

Nutritional value

Processed cow’s milk was formulated to contain differing amounts of fat during the 1950s. One cup (250 mL) of 2%-fat cow’s milk contains 285 mg of calcium, which represents 22% to 29% of the daily recommended intake (DRI) of calcium for an adult. Depending on its age, milk contains 8 grams of protein, and a number of other nutrients^[which?] (either naturally or through fortification).

Allergy

One of the most common food allergies in infants is to cow’s milk. This is an immunologically mediated adverse reaction, rarely fatal, to one or more cow’s milk proteins.^[100] Milk allergy affects between 2% and 3% of babies and young children.^[101] To reduce risk, recommendations are that babies should be exclusively breastfed for at least four months, preferably six months, before introducing cow’s milk.^[102] The majority of children outgrow milk allergy, but for about 0.4% the condition persists into adulthood.^[103]

Lactose intolerance

Lactose intolerance is a condition in which people have symptoms due to deficiency or absence of the enzyme lactase in the small intestine, causing poor absorption of milk lactose.^[104][105] People affected vary in the amount of lactose they can tolerate before symptoms develop,^[104] which may include abdominal pain, bloating, diarrhea, gas, and nausea.^[104] Severity depends on the amount of milk consumed.^[104] Those affected are usually able to drink at least one cup of milk without developing significant symptoms, with greater amounts tolerated if drunk with a meal or throughout the day.^[104][106]

Evolution of lactation

The mammary gland is thought to have derived from apocrine skin glands.^[107] It has been suggested that the original function of lactation (milk production) was keeping eggs moist. Much of the argument is based on monotremes (egg-laying mammals).^{[107][108][109]} The original adaptive significance of milk secretions may have been nutrition^[110] or immunological protection.^[111][112] This secretion gradually became more copious and accrued nutritional complexity over evolutionary time.^[107]

Tritylodontid cynodonts seem to have displayed lactation, based on their dental replacement patterns.^[113]

Bovine growth hormone supplementation

Since November 1993, recombinant bovine somatotropin (rbST), also called rBGH, has been sold to dairy farmers with FDA approval. Cows produce bovine growth hormone naturally, but some producers administer an additional recombinant version of BGH which is produced through genetically engineered E. coli to increase milk production. Bovine growth hormone also stimulates liver production of insulin-like growth factor 1 (IGF1). The US Food and Drug Administration,^[114] the National Institutes of Health^[115] and the World Health Organization^[116] have reported that both of these compounds are safe for human consumption at the amounts present.

Milk from cows given rBST may be sold in the United States, and the FDA stated that no significant difference has been shown between milk derived from rBST-treated and that from non-rBST-treated cows.^[117] Milk that advertises that it comes from cows not treated with rBST, is required to state this finding on its label.

Cows receiving rBGH supplements may more frequently contract an udder infection known as mastitis.^[118] Problems with mastitis have led to Canada, Australia, New Zealand, and Japan banning milk from rBST treated cows. Mastitis, among other diseases, may be responsible for the fact that levels of white blood cells in milk vary naturally.^[119][120]

rBGH is also banned in the European Union, for reasons of animal welfare.^[121]

Varieties and brands

Milk products are sold in a number of varieties based on types/degrees of:

• additives (e.g. vitamins, flavorings)
• age (e.g. cheddar, old cheddar)
• coagulation (e.g. cottage cheese)
• farming method (e.g. organic, grass-fed, haymilk)
• fat content (e.g. half and half, 3% fat milk, 2% milk, 1% milk, skim milk)
• fermentation (e.g. buttermilk)
• flavoring (e.g. chocolate and strawberry)
• homogenization (e.g. cream top)
• packaging (e.g. bottle, carton, bag)
• pasteurization (e.g. raw milk, pasteurized milk)
• reduction or elimination of lactose
• species (e.g. cow, goat, sheep)
• sweetening (e.g., chocolate and strawberry milk)
• water content (e.g. dry milk powder, condensed milk, ultrafiltered milk)

Milk preserved by the UHT process does not need to be refrigerated before opening and has a much longer shelf life (six months) than milk in ordinary packaging. It is typically sold unrefrigerated in the UK, US, Europe, Latin America, and Australia.

Reduction or elimination of lactose

Lactose-free milk can be produced by passing milk over lactase enzyme bound to an inert carrier. Once the molecule is cleaved, there are no lactose ill effects. Forms are available with reduced amounts of lactose (typically 30% of normal), and alternatively with nearly 0%. The only noticeable difference from regular milk is a slightly sweeter taste due to the cleavage of lactose into glucose and galactose. Lactose-reduced milk can also be produced via ultra filtration, which removes smaller molecules such as lactose and water while leaving calcium and proteins behind. Milk produced via these methods has a lower sugar content than regular milk.^[90] To aid digestion in those with lactose intolerance, another alternative is dairy foods, milk and yogurt, with added bacterial cultures such as Lactobacillus acidophilus («acidophilus milk») and bifidobacteria.^[122] Another milk with Lactococcus lactis bacteria cultures («cultured buttermilk») often is used in cooking to replace the traditional use of naturally soured milk, which has become rare due to the ubiquity of pasteurization, which also kills the naturally occurring Lactococcus bacteria.^[123]

Additives and flavoring

Commercially sold milk commonly has vitamin D added to it to make up for lack of exposure to UVB radiation. Reduced-fat milks often have added vitamin A palmitate to compensate for the loss of the vitamin during fat removal; in the United States this results in reduced fat milks having a higher vitamin A content than whole milk.^[124] Milk often has flavoring added to it for better taste or as a means of improving sales. Chocolate milk has been sold for many years and has been followed more recently by strawberry milk and others. Some nutritionists have criticized flavored milk for adding sugar, usually in the form of high-fructose corn syrup, to the diets of children who are already commonly obese in the US.^[125]

Distribution

Due to the short shelf life of normal milk, it used to be delivered to households daily in many countries; however, improved refrigeration at home, changing food shopping patterns because of supermarkets, and the higher cost of home delivery mean that daily deliveries by a milkman are no longer available in most countries.

Australia and New Zealand

In Australia and New Zealand, prior to metrication, milk was generally distributed in 1 pint (568 mL) glass bottles. In Australia and Ireland there was a government funded «free milk for school children» program, and milk was distributed at morning recess in 1/3 pint bottles. With the conversion to metric measures, the milk industry was concerned that the replacement of the pint bottles with 500 mL bottles would result in a 13.6% drop in milk consumption; hence, all pint bottles were recalled and replaced by 600 mL bottles. With time, due to the steadily increasing cost of collecting, transporting, storing and cleaning glass bottles, they were replaced by cardboard cartons. A number of designs were used, including a tetrahedron which could be close-packed without waste space, and could not be knocked over accidentally (slogan: «No more crying over spilt milk»). However, the industry eventually settled on a design similar to that used in the United States.^[126]

Milk is now available in a variety of sizes in paperboard milk cartons (250 mL, 375 mL, 600 mL, 1 liter and 1.5 liters) and plastic bottles (1, 2 and 3 liters). A significant addition to the marketplace has been «long-life» milk (UHT), generally available in 1 and 2 liter rectangular cardboard cartons. In urban and suburban areas where there is sufficient demand, home delivery is still available, though in suburban areas this is often 3 times per week rather than daily. Another significant and popular addition to the marketplace has been flavored milks; for example, as mentioned above, Farmers Union Iced Coffee outsells Coca-Cola in South Australia.^[127]

India

In rural India, milk is home delivered, daily, by local milkmen carrying bulk quantities in a metal container, usually on a bicycle. In other parts of metropolitan India, milk is usually bought or delivered in plastic bags or cartons via shops or supermarkets.

The current milk chain flow in India is from milk producer to milk collection agent. Then it is transported to a milk chilling center and bulk transported to the processing plant, then to the sales agent and finally to the consumer.

A 2011 survey by the Food Safety and Standards Authority of India found that nearly 70% of samples had not conformed to the standards set for milk. The study found that due to lack of hygiene and sanitation in milk handling and packaging, detergents (used during cleaning operations) were not washed properly and found their way into the milk. About 8% of samples in the survey were found to have detergents, which are hazardous to health.^[128]

Pakistan

In Pakistan, milk is supplied in jugs. Milk has been a staple food, especially among the pastoral tribes in this country.

United Kingdom

Since the late 1990s, milk-buying patterns have changed drastically in the UK. The classic milkman, who travels his local milk round (route) using a milk float (often battery powered) during the early hours and delivers milk in 1-pint glass bottles with aluminum foil tops directly to households, has almost disappeared. Two of the main reasons for the decline of UK home deliveries by milkmen are household refrigerators (which lessen the need for daily milk deliveries) and private car usage (which has increased supermarket shopping). Another factor is that it is cheaper to purchase milk from a supermarket than from home delivery. In 1996, more than 2.5 billion liters of milk were still being delivered by milkmen, but by 2006 only 637 million liters (13% of milk consumed) was delivered by some 9,500 milkmen.^[129] By 2010, the estimated number of milkmen had dropped to 6,000.^[130] Assuming that delivery per milkman is the same as it was in 2006, this means milkmen deliveries now only account for 6–7% of all milk consumed by UK households (6.7 billion liters in 2008/2009).^[131]

Almost 95% of all milk in the UK is thus sold in shops today, most of it in plastic bottles of various sizes, but some also in milk cartons. Milk is hardly ever sold in glass bottles in UK shops.

United States

In the United States, glass milk bottles have been replaced mostly with milk cartons and plastic jugs. Gallons of milk are almost always sold in jugs, while half gallons and quarts may be found in both paper cartons and plastic jugs, and smaller sizes are almost always in cartons.

The «half pint» (237 mL, 5⁄12 imp pt) milk carton is the traditional unit as a component of school lunches, though some companies have replaced that unit size with a plastic bottle, which is also available at retail in 6- and 12-pack size.

Packaging

Glass milk bottles are now rare. Most people purchase milk in bags, plastic bottles, or plastic-coated paper cartons. Ultraviolet (UV) light from fluorescent lighting can alter the flavor of milk, so many companies that once distributed milk in transparent or highly translucent containers are now using thicker materials that block the UV light.
Milk comes in a variety of containers with local variants:

Argentina

Commonly sold in 1-liter bags and cardboard boxes. The bag is then placed in a plastic jug and the corner cut off before the milk is poured.

Australia and New Zealand

Distributed in a variety of sizes, most commonly in aseptic cartons for up to 1.5 liters, and plastic screw-top bottles beyond that with the following volumes; 1.1 L, 2 L, and 3 L. 1-liter milk bags are starting to appear in supermarkets, but have not yet proved popular. Most UHT-milk is packed in 1 or 2 liter paper containers with a sealed plastic spout.^[126]

Brazil

Used to be sold in cooled 1-liter bags, just like in South Africa. Today the most common form is 1-liter aseptic cartons containing UHT skimmed, semi-skimmed or whole milk, although the plastic bags are still in use for pasteurized milk. Higher grades of pasteurized milk can be found in cartons or plastic bottles. Sizes other than 1-liter are rare.

Canada

1.33 liter plastic bags (sold as 4 liters in 3 bags) are widely available in some areas (especially the Maritimes, Ontario and Quebec), although the 4 liter plastic jug has supplanted them in western Canada. Other common packaging sizes are 2 liter, 1 liter, 500 mL, and 250 mL cartons, as well as 4 liter, 1 liter, 250 mL aseptic cartons and 500 mL plastic jugs.

Chile

Distributed most commonly in aseptic cartons for up to 1 liter, but smaller, snack-sized cartons are also popular. The most common flavors, besides the natural presentation, are chocolate, strawberry and vanilla.

China

Sweetened milk is a drink popular with students of all ages and is often sold in small plastic bags complete with straw. Adults not wishing to drink at a banquet often drink milk served from cartons or milk tea.

Colombia

Sells milk in 1-liter plastic bags.

Croatia, Bosnia and Herzegovina, Serbia, Montenegro

UHT milk (trajno mlijeko/trajno mleko/трајно млеко) is sold in 500 mL and 1 L (sometimes also 200 mL) aseptic cartons. Non-UHT pasteurized milk (svježe mlijeko/sveže mleko/свеже млеко) is most commonly sold in 1 L and 1.5 L PET bottles, though in Serbia one can still find milk in plastic bags.

Estonia

Commonly sold in 1 L bags or 0.33 L, 0.5 L, 1 L or 1.5 L cartons.

Parts of Europe

Sizes of 500 mL, 1 liter (the most common), 1.5 liters, 2 liters and 3 liters are commonplace.

Finland

Commonly sold in 1 L or 1.5 L cartons, in some places also in 2 dl and 5 dl cartons.

Germany

Commonly sold in 1-liter cartons. Sale in 1-liter plastic bags (common in the 1980s) is now rare.

Hong Kong

Milk is sold in glass bottles (220 mL), cartons (236 mL and 1 L), plastic jugs (2 liters) and aseptic cartons (250 mL).

India

Commonly sold in 500 mL plastic bags and in bottles in some parts like in the West. It is still customary to serve the milk boiled, despite pasteurization. Milk is often buffalo milk. Flavored milk is sold in most convenience stores in waxed cardboard containers. Convenience stores also sell many varieties of milk (such as flavored and ultra-pasteurized) in various sizes, usually in aseptic cartons.

Indonesia

Usually sold in 1-liter cartons, but smaller, snack-sized cartons are available.

Italy

Commonly sold in 1-liter cartons or bottles and less commonly in 0.5 or 0.25-liter cartons. Whole milk, semi-skimmed milk, skimmed, lactose-free, and flavored (usually in small packages) milk is available. Milk is sold fresh or UHT. Goat’s milk is also available in small amounts. UHT semi-skimmed milk is the most sold, but cafés use almost exclusively fresh whole milk.

Japan

Commonly sold in 1-liter waxed paperboard cartons. In most city centers there is also home delivery of milk in glass jugs. As seen in China, sweetened and flavored milk drinks are commonly seen in vending machines.

Kenya

Milk in Kenya is mostly sold in plastic-coated aseptic paper cartons supplied in 300 mL, 500 mL or 1 liter volumes. In rural areas, milk is stored in plastic bottles or gourds.^[132][133] The standard unit of measuring milk quantity in Kenya is a liter.

Pakistan

Milk is supplied in 500 mL plastic bags and carried in jugs from rural to cities for selling

Philippines

Milk is supplied in 1000 mL plastic bottles and delivered from factories to cities for selling.

Poland

UHT milk is mostly sold in aseptic cartons (500 mL, 1 L, 2 L), and non-UHT in 1 L plastic bags or plastic bottles. Milk, UHT is commonly boiled, despite being pasteurized.

South Africa

Commonly sold in 1-liter bags. The bag is then placed in a plastic jug and the corner cut off before the milk is poured.

South Korea

Sold in cartons (180 mL, 200 mL, 500 mL 900 mL, 1 L, 1.8 L, 2.3 L), plastic jugs (1 L and 1.8 L), aseptic cartons (180 mL and 200 mL) and plastic bags (1 L).

Sweden

Commonly sold in 0.3 L, 1 L or 1.5 L cartons and sometimes as plastic or glass milk bottles.

Turkey

Commonly sold in 500 mL or 1L cartons or special plastic bottles. UHT milk is more popular. Milkmen also serve in smaller towns and villages.

United Kingdom

Most stores stock imperial sizes: 1 pint (568 mL), 2 pints (1.136 L), 4 pints (2.273 L), 6 pints (3.408 L) or a combination including both metric and imperial sizes. Glass milk bottles delivered to the doorstep by the milkman are typically pint-sized and are returned empty by the householder for repeated reuse. Milk is sold at supermarkets in either aseptic cartons or HDPE bottles. Supermarkets have also now begun to introduce milk in bags, to be poured from a proprietary jug and nozzle.

United States

Commonly sold in gallon (3.78 L), half-gallon (1.89 L) and quart (0.94 L) containers of natural-colored HDPE resin, or, for sizes less than one gallon, cartons of waxed paperboard. Bottles made of opaque PET are also becoming commonplace for smaller, particularly metric, sizes such as one liter. The US single-serving size is usually the half-pint (about 240 mL). Less frequently, dairies deliver milk directly to consumers, from coolers filled with glass bottles which are typically half-gallon sized and returned for reuse. Some convenience store chains in the United States (such as Kwik Trip in the Midwest) sell milk in half-gallon bags, while another rectangular cube gallon container design used for easy stacking in shipping and displaying is used by warehouse clubs such as Costco and Sam’s Club, along with some Walmart stores.^[134]

Uruguay

Pasteurized milk is commonly sold in 1-liter bags and ultra-pasteurized milk is sold in cardboard boxes called Tetra Briks. Non-pasteurized milk is forbidden. Until the 1960s no treatment was applied; milk was sold in bottles. As of 2017, plastic jugs used for pouring the bags, or «sachets», are in common use.

Practically everywhere, condensed milk and evaporated milk are distributed in metal cans, 250 and 125 mL paper containers and 100 and 200 mL squeeze tubes, and powdered milk (skim and whole) is distributed in boxes or bags.

Spoilage and fermented milk products

When raw milk is left standing for a while, it turns «sour». This is the result of fermentation, where lactic acid bacteria ferment the lactose in the milk into lactic acid. Prolonged fermentation may render the milk unpleasant to consume. This fermentation process is exploited by the introduction of bacterial cultures (e.g. Lactobacilli sp., Streptococcus sp., Leuconostoc sp., etc.) to produce a variety of fermented milk products. The reduced pH from lactic acid accumulation denatures proteins and causes the milk to undergo a variety of different transformations in appearance and texture, ranging from an aggregate to smooth consistency. Some of these products include sour cream, yogurt, cheese, buttermilk, viili, kefir, and kumis. See Dairy product for more information.

Pasteurization of cow’s milk initially destroys any potential pathogens and increases the shelf life,^[135][136] but eventually results in spoilage that makes it unsuitable for consumption. This causes it to assume an unpleasant odor, and the milk is deemed non-consumable due to unpleasant taste and an increased risk of food poisoning. In raw milk, the presence of lactic acid-producing bacteria, under suitable conditions, ferments the lactose present to lactic acid. The increasing acidity in turn prevents the growth of other organisms, or slows their growth significantly. During pasteurization, however, these lactic acid bacteria are mostly destroyed.

In order to prevent spoilage, milk can be kept refrigerated and stored between 1 and 4 °C (34 and 39 °F) in bulk tanks. Most milk is pasteurized by heating briefly and then refrigerated to allow transport from factory farms to local markets. The spoilage of milk can be forestalled by using ultra-high temperature (UHT) treatment. Milk so treated can be stored unrefrigerated for several months until opened but has a characteristic «cooked» taste. Condensed milk, made by removing most of the water, can be stored in cans for many years, unrefrigerated, as can evaporated milk.

Powdered milk

The most durable form of milk is powdered milk, which is produced from milk by removing almost all water. The moisture content is usually less than 5% in both drum- and spray-dried powdered milk.

Freezing of milk can cause fat globule aggregation upon thawing, resulting in milky layers and butterfat lumps. These can be dispersed again by warming and stirring the milk.^[137] It can change the taste by destruction of milk-fat globule membranes, releasing oxidized flavors.^[137]

Use in other food products

Milk is used to make yogurt, cheese, ice milk, pudding, hot chocolate and french toast, among many other products. Milk is often added to dry breakfast cereal, porridge and granola. Milk is mixed with ice cream and flavored syrups in a blender to make milkshakes. Milk is often served in coffee and tea. Frothy steamed milk is used to prepare espresso-based drinks such as cafe latte.

In language and culture

The importance of milk in human culture is attested to by the numerous expressions embedded in our languages, for example, «the milk of human kindness», the expression «there’s no use crying over spilt milk» (which means don’t «be unhappy about what cannot be undone»), «don’t milk the ram» (this means «to do or attempt something futile») and «Why buy a cow when you can get milk for free?» (which means «why pay for something that you can get for free otherwise»).^[138]

In Greek mythology, the Milky Way was formed after the trickster god Hermes suckled the infant Heracles at the breast of Hera, the queen of the gods, while she was asleep.^[139][140] When Hera awoke, she tore Heracles away from her breast and splattered her breast milk across the heavens.^[139][140] In another version of the story, Athena, the patron goddess of heroes, tricked Hera into suckling Heracles voluntarily,^[139][140] but he bit her nipple so hard that she flung him away, spraying milk everywhere.^[139][140]

In many African and Asian countries, butter is traditionally made from fermented milk rather than cream. It can take several hours of churning to produce workable butter grains from fermented milk.^[141]

Holy books have also mentioned milk. The Bible contains references to the «Land of Milk and Honey» as a metaphor for the bounty of the Promised Land. In the Qur’an, there is a request to wonder on milk as follows: «And surely in the livestock there is a lesson for you, We give you to drink of that which is in their bellies from the midst of digested food and blood, pure milk palatable for the drinkers» (16-The Honeybee, 66). The Ramadan fast is traditionally broken with a glass of milk and dates.

Abhisheka is conducted by Hindu and Jain priests, by pouring libations on the idol of a deity being worshipped, amidst the chanting of mantras. Usually offerings such as milk, yogurt, ghee, honey may be poured among other offerings depending on the type of abhishekam being performed.

A milksop is an «effeminate spiritless man,» an expression which is attested to in the late 14th century.^[11] Milk toast is a dish consisting of milk and toast. Its soft blandness served as inspiration for the name of the timid and ineffectual comic strip character Caspar Milquetoast, drawn by H. T. Webster from 1924 to 1952.^[142] Thus, the term «milquetoast» entered the language as the label for a timid, shrinking, apologetic person. Milk toast also appeared in Disney’s Follow Me Boys as an undesirable breakfast for the aging main character Lem Siddons.

To «milk» someone, in the vernacular of many English-speaking countries, is to take advantage of the person, by analogy to the way a farmer «milks» a cow and takes its milk. The word «milk» has had many slang meanings over time. In the 19th century, milk was used to describe a cheap and very poisonous alcoholic drink made from methylated spirits (methanol) mixed with water. The word was also used to mean defraud, to be idle, to intercept telegrams addressed to someone else, and a weakling or «milksop.» In the mid-1930s, the word was used in Australia to refer to siphoning gas from a car.^[143]

Non-culinary uses

Besides serving as a beverage or source of food, milk has been described as used by farmers and gardeners as an organic fungicide and fertilizer,^{[144][145][146]} however, its effectiveness is debated. Diluted milk solutions have been demonstrated to provide an effective method of preventing powdery mildew on grape vines, while showing it is unlikely to harm the plant.^[147][148]

Milk paint is a nontoxic water-based paint. It can be made from milk and lime, generally with pigments added for color.^{[149][150][151]} In other recipes, borax is mixed with milk’s casein protein in order to activate the casein and as a preservative.^[152][153]

Milk has been used for centuries as a hair and skin treatment.
^[154] Hairstylist Richard Marin states that some women rinse their hair with milk to add a shiny appearance to their hair.^[154] Cosmetic chemist Ginger King states that milk can «help exfoliate and remove debris [from skin] and make hair softer. Hairstylist Danny Jelaca states that milk’s keratin proteins may «add weight to the hair».^[154] Some commercial hair products contain milk.^[154]

A milk bath is a bath taken in milk rather than just water. Often additives such as oatmeal, honey, and scents such as rose, daisies and essential oils are mixed in. Milk baths use lactic acid, an alpha hydroxy acid, to dissolve the proteins which hold together dead skin cells.^[155]

Interspecies milk consumption

The consumption of milk between species is not unique to humans. Seagulls, Sheathbills, Skuas, Western Gulls and African feral cats have been reported to directly pilfer milk from the elephant seals’ teats.^{[156][157][158][159]}

Jewish/Kosher milk

Chalav Yisrael is the term of Jewish religious law regulating consumption of milk.^{[160][161][162]}

See also

References

Further reading

• Dillon, John J. Seven decades of milk,: A history of New York’s dairy industry (1941)
• Innis, Harold A. The dairy industry in Canada (1937) online
• Kardashian, Kirk. Milk Money: Cash, Cows, and the Death of the American Dairy Farm (2012)
• Kurlansky, Mark. Milk: A 10,000-Year History (2019); also published as Milk!: A 10,000-Year Food Fracas (2019)
• McGee, Harold (2004). On Food and Cooking (2nd ed.). New York: Scribner. ISBN 978-0-684-80001-1.
• Prasad, Rajendra (2017). «Historical Aspects of Milk Consumption in South, Southeast, and East Asia» (PDF). Asian Agricultural History. 21 (4): 287–307.
• Scherbaum, Veronika; Srour, M. Leila (2018). «Milk products in the dietary management of childhood undernutrition – a historical review» (PDF). Nutrition Research Reviews. 31 (1): 71–84. doi:10.1017/s0954422417000208. PMID 29113618. S2CID 910669. Archived from the original (PDF) on February 12, 2020.
• Smith-Howard, Kendra. Pure and Modern Milk: An Environmental History Since 1900. (Oxford University Press; 2013).
• Valenze, Deborah. Milk: A Local and Global History (Yale University Press, 2011) 368 pp.
• Wiley, Andrea. Re-imagining Milk: Cultural and Biological Perspectives (Routledge 2010) (Series for Creative Teaching and Learning in Anthropology)

External links

• Milk at Curlie
• Searchable nutrition charts by various categories of milk products

Sweet milk! It is the first food among most warm-blooded creatures of the Earth. As babies, it is pure sustenance. As we grow older, it provides the nutrients to keep our bodies and muscles strong. We mix it with our coffee and tea, use it as a basis for our cheeses and yogurts, and even create our deserts with it, like milk chocolate and ice cream. One would have to truly call it the «drink of life.»

A young sheep, drinking milk from its mother.

We can get milk from most mammals. The English word «mammal» comes from the Latin word mamma meaning «breast», which is where milk comes from.

The word «milk» in English has its roots in an Indo-European word «melg» which meant «wiping or stroking.» This was the method of getting the liquid from an animal’s udders. The verb then got its meaning transferred to the substance it produces. This is how we still use the term… we get our «milk» from «milking» a cow. The «melg» got passed into the Germanic languages as «melk,» which became the base «meluks.» This led to most of the modern Germanic words: Dutch (melk), German (Milch), Yiddish (milkh), and Faroese (mjólk).

The root «melg» seems to have also been picked up in the Old Teutonic, which is often the root for the Slavic words. However, while it also transferred the «g» to a «k» sound, somewhere the «e» and «l» seems to have gotten transposed as well, as can be seen among the Slavic words: Polish (mleko), Russian (молоко), Croatian (mlijeko), and Kashubian (mlékò).

Among the Italic languages, a common root is normally found in Latin, and this is no exception. The ancient Latin root was «lac,» which actually did refer to the substance. It gave us the Latin verb lactare, meaning «to suckle.» From there, the modern derivatives can be seen clearly: Italian (latte), Spanish (leche), Catalan (llet), and Romanian (lapte). Notice that in most cases, the «c» was dropped. In a few, it was replaced by another letter. It is also interesting to note that while the shift in the Germanic and Slavic came from a verb into a noun, the Italic came from a noun into a verb.

People observing the cows of a dairy farm, Varmakeldugarðurin («The Hot Springs Farm»), on the island island of Eysturoy, Faroe Islands.

The word for «milk» in Old Irish was «lacht,» taken from the Latin «lac» as well. «Lacht» is used now to refer more strictly to cow’s milk. Old Irish «bannae» had the primary meaning of «drop,» but then the meaning transferred to «drop of milk,» then simply to «milk.» From that, we get these Gaelic words: Irish (bainne), Manx (bainney), and Scottish Gaelic (bainne).

The Malay word «susu» originally meant «breast,» and the expression «air susu» meant «breast water,» or «milk.» This later got shortened to simply «susu,» with the meaning being transferred.

What is particularly interesting to note is that in some languages, the words for «milk» and «breasts» are related or identical, while in other languages, they seem to be totally unrelated. Some reasons for this could be meaning transfers, word «borrowing» from other languages, or simply drawing the words from two entirely different bases.

In English, «milk» can be used as both a noun and verb, with «to milk» being the process of getting the milk. This word similarity between noun and verb forms is ound in some languages and not in others. The words for «milk / to milk» are latte / mungere in Italian, leche / ordeñar in Spanish, Milch / milchen in German, melk / melke in Norwegian, and малако / малочны in Belarusian.

Related Derivatives

Shelves full of containers of milk in a supermarket.

The process of milk coming from a breast, «lactation,» obviously has its root from the Latin «lac,» which also shows again how English draws from so many sources; it draws «milk» from a Germanic origin, but «giving milk» from a Latin origin. A less obvious derivative is the salad standard «lettuce.» It also comes from the Latin, and was given this connection because when one cuts into fresh lettuce, a white, watery, «milky» substance flows out. However, this connection is not drawn in most of the other languages.

Slang

Since milk is so close to our basic existence, a number of the slang terms refer to its purity. «Mother’s Milk» is used to describe something that is wholesome. «Milk and Honey» is used to describe the richness of a land. When we make a big deal over something simple, we are told, «Don’t cry over spilt milk.» When we take advantage of a situation, usually one in which we shouldn’t, we are said to be «milking it.»

Conclusion

I was surprised at how direct the connections were between the modern words for «milk» and their origins. It only reinforces how important this liquid is to our lives and health, how much we cherish it. And I was also surprised I managed to write this article without making too many embarrassing references to breasts. I could have really milked those!

«Milk» in many languages

GERMANIC
Western
Afrikaans:	melk
Dutch:	melk
English:	milk
Frisian:	molke
German:	Milch
Limburgian:	milk
Luxembourgish:	Mëllech
Scots:	melk
Swiss German:	Milch
Yiddish:	milkh
Northern (+ def. articles)
Danish:	mælk(-en)
Faroese:	mjólk(-en)
Icelandic:	mjólk(-in)
Swedish:	mjölk(-en)
Norwegian (Bokmål):	melk(-en)
Norwegian (Nynorsk):	mjølk(-en)

SLAVIC
Western
Czech:	mléko
Kashubian:	mlékò
Polabian:	mlaka
Polish:	mleko
Slovak:	mlieko
Eastern
Byelorussian:	малако
Russian:	молоко
Ukrainian:	молоко
Southern
Bulgarian:	мляко
Croatian:	mlijeko
Macedonian:	млеко
Slovenian:	mleko
Serbian:	млеко [mleko]

ITALIC
Aragones:	lei
Asturian:	lleche ; ferventáu ; maciadura ; zarapacha
Bergamasco:	lac’
Biellese:	lacc
Bolognese:	lât
Bresciano:	lat
Calabrese:	latti ; latta
Catalan:	llet
Dzoratâi:	lacî
French:	lait
Galician:	leite
Italian:	latte
Judeo-Spanish:	leche
Ladino:	lat
Latin:	lac
Leonese:	lleche
Lombardo Occidentale:	latt ; lacc
Mantuan:	lat
Mudnés:	lat
Neapolitan:	latte
Occitan:	lait
Parmigiano:	laat
Piemontese:	làit
Portuguese:	leite
Pugliese:	latte
Reggiano:	lat
Romagnolo:	làt
Romanian:	lapte
Romansh:	latg
Sardinian (Limba Sarda Unificada):	late
Sardinian Campidanesu:	latti
Sardinian Logudoresu:	latte
Sicilian:	latti
Spanish:	leche
Triestino:	late
Valencian:	llet
Venetian:	late
Viestano:	latt’
Wallon:	lècê
Zeneize:	læte

ALBANIAN
Albanian:	qumësht

GREEK
Greek:	γάλα
Griko Salentino:	gàla
Old Greek:	γάλα

ALTAIC
Azeri (Latin Script):	süd
Korean:	우유 / 젖
Mongolian:	сүү
Turkish:	süt
Tatar:	söt
Turkmen:	süÿt

CELTIC
Goidelic
Irish:	bainne
Manx:	bainney
Scottish Gaelic:	bainne
Brythonic
Welsh:	llaeth
Breton:	laezh

INDEPENDENT
Japanese:	乳汁 [にゅうじゅう] / 牛乳 [ぎゅうにゅう] / ミルク
Basque :	esne

FINNO-UGRIC
Estonian:	piim
Finnish:	maito
Hungarian:	tej
Mokshan:	loftsa
Saami:	mielki

CAUCASIAN
Chechen:	shura
Georgian:	რძე

MALAYO-POLYNESIAN
Bahasa Indonesian:	susu
Malagasy:	ronono
Malay:	susu
Reo Māori (NZ):	miraka (of animals) / waiū
ReoMāori (CI):	vaiū
Reo Māohi:	vaiū
`Ōlelo Hawai`i:	waiū
Vānanga Rapa Nui:	vaiū
Samoan:	susu
Tetun:	Susu ben

MESO-PHILIPPINE
Tagalog:	gatas

AFRO-ASIATIC
Somali:	caano

SEMITIC
Arabic:	حليب [haliib] /لبن [laban]
Hebrew:	חלב
Maltese:	halib

SINO-TIBETAN
Chinese:	牛奶 [niu2 nai3]

AUSTROASIATIC
Vietnamese:	sữa

BALTIC
Latvian:	piens
Lithuanian:	pienas

INDO-IRANIAN
Hindi:	दूध
Kurdish Kurmanji:	şîr
Kurdish Sorani:	شير
Persian:	شير

NILO-SAHARAN
Ferrarese:	lat
Maasai:	kule

NIGER-KHORDOFANIAN
Lingala:	miliki / mabele
Shona:	mukaka
Swahili:	maziwa

ANDEAN-EQUATORIAL
Aymara:	millk’i / millk’a
Quechua (Ecuador):	ñuñu
Quechua (Peruvian?):	pilli

CREOLE
Caló:	cheripí / chutí

CONSTRUCTED
Canis:	lata
Esperanto:	lakto
Interlingua:	lacte
Lingua Franca Nova:	lete
Volapük:	milig

IV.
Открытие нового знания

Работа
с книгой – чтение

Словесный
– беседа

15
мин

-What can you see on these pictures?

-could
it be a farm?

-Complete
the sentences. Example: cheese comes from a goat .  The sweater comes
from … ; eggs come from …;  honey comes from …; milk comes from… .

-Good!

-Look
at the screen.

-Listen
to me.  New words:

Mr.
Day

London
[‘lΛndәn]- Лондон

 much
work to do schoolchildren [‘sku:l’t∫ildrәn] – много работы для школьников

a
bottle [botl] — бутылка

— Repeat after me
all together. —

 Listen to the
story “Milk comes from cows, not bottles”

      Mr Day
lives in London. Every morning he gets up at five o’clock — he has got a farm
in the centre of London. He has got much work to do on his farm.
      Schoolchildren visit the farm from all over London. There are many different
animals on the farm: cows , horses, pigs, sheep, ducks, chickens.
      Many London children see farm animals only on TV or in a book. They
don»t know about cows.»Milk comes from bottles,» they think.
      After their visit to the farm they know- milk comes from cows ,not
bottles.

-Do you understand the text?

-Answer my questions on the text.

1. Where does Mr
Day live?
2. Has he got a farm or a zoo?
3.What time does he get up?
4.What animals are there on the farm?
5.Why do some London children think that milk comes from bottles, not cows?

-listen to the text.

-Look
at the screen.

—Choose the
correct answer: 

1. Where
   does Mr. Day live?

a)       in Oxford  b) in
London  c) in Moscow

1. What
   does he have?

a)       a car  b) a big
house  c) a farm

1. What
   time does he get up?

a)       at five o’clock 
b) at six o’clock  c) at nine o’clock

1. What
   domestic animals are there on the farm?

a)       a tiger, a lion,
a monkey, an elephant

b)       cows, horses,
pigs, sheep

c)       dogs, cats,
parrots, tortoises

1. What
   do the schoolchildren visit?

a)       a park  b) a
zoo  c) a farm

1. What
   do the children learn?

            
They learn that  a) milk comes from cows

                                      
b) milk comes from bottles

                                      
c) milk comes from shops  

it’s
animals

 yes,
it’s farm

The
sweater comes from a sheep; eggs come from a chicken; honey comes from a
bees; milk comes from a cow .

Читают
новые слова

Yes/no

1.
He lives in London.

2.
He has got a farm.

3.
He gets up at 5 (five) o`clock

4.
In his farm are there cows, horses, pigs, sheep, ducks, chickens.

5. Because they
see on farm animals only in books or TV. 

Слушают текст еще раз

Choose the
correct answer: 

1- b

2-c

3-a

4-d

5-c

6-a

Умение
анализировать, развитие языковой догадки (П.)

Умение
высказывать и аргументировать свое мнение (К.)

Усвоение
и анализ новой информации, выполнение практических заданий, усвоение приемов
решения учебных задач (П.)