Milk

Milk
Foremilk and Hindmilk samples of human breast milk
A glass of pasteurized cow milk

Milk is a white liquid produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals before they are able to digest other types of food. Early-lactation milk contains colostrum, which carries the mother's antibodies to the baby and can reduce the risk of many diseases in the baby. The precise components of raw milk vary by species and by a number of other factors, but it contains significant amounts of saturated fat, protein and calcium as well as vitamin C. Cow's milk has a pH ranging from 6.4 to 6.8, making it slightly acidic.[1][2]

Contents

Types of consumption

There are two distinct types of milk consumption: a natural source of nutrition for all infant mammals and a food product for humans of all ages that is derived from other animals.

Nutrition for infant mammals

A human baby feeding on its mother's milk
A 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. Some cultures, historically or currently, continue to use breast milk to feed their children until they are seven years old.[citation needed]

Human infants sometimes are fed fresh goat milk. There are known risks in this practice, including those of developing electrolyte imbalances, metabolic acidosis, megaloblastic anemia, and a host of allergic reactions.[3]

Food product for humans

Holstein cattle, the dominant breed in industrialized dairying today

In many cultures of the world, especially the Western world, humans continue to consume milk beyond infancy, using the milk of other animals (especially cattle, goats and sheep) as a food product. For millennia, cow's milk has been processed into dairy products such as cream, butter, yogurt, kefir, ice cream, and especially the more durable and easily transportable product, cheese. Modern industrial processes produce casein, whey protein, lactose, condensed milk, powdered milk, and many other food-additive and industrial products.

Humans are an exception in the natural world for consuming milk past infancy, despite the fact that many humans show some degree (some as little as 5%) of lactose intolerance, a characteristic that is more prevalent among individuals of African or Asian descent.[4] 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 small intestines after birth and then begins a slow decline unless milk is consumed regularly.[5] On the other hand, those groups who do continue to tolerate milk often have exercised great creativity in using the milk of domesticated ungulates, not only of cattle, but also sheep, goats, yaks, water buffalo, horses, reindeers and camels. The largest producer and consumer of cattle and buffalo milk in the world is India.[6]

Top ten per capita cow's milk and cow's milk products consumers in 2006[7]
Country Milk (liters) Cheese (kg) Butter (kg)
 Finland 183.9 19.1 5.3
 Sweden 145.5 18.5 1.0
 Ireland 129.8 10.5 2.9
 Netherlands 122.9 20.4 3.3
 Norway 116.7 16.0 4.3
 Spain 119.1 9.6 1.0
 Switzerland 112.5 22.2 5.6
 United Kingdom 111.2 12.2 3.7
 Australia 106.3 11.7 3.7
 Canada 94.7 12.2 3.3

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.[8] In 2010 the Department of Agriculture predicted farmers would receive an average of $1.35 per US 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.[9]

Terminology

The term milk is also used for white colored, non-animal beverages resembling milk in color and texture such as soy milk, rice milk, almond milk, and coconut milk. In addition, a substance secreted by pigeons to feed their young is called crop milk and bears some resemblance to mammalian milk.[10] Dairy relates to milk and milk production, eg. dairy products.

Evolution of lactation

Drinking milk in Germany in 1932

The mammary gland is thought to have been derived from apocrine skin glands.[11] 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):[11][12][13] The original adaptive significance of milk secretions may have been nutrition[14] or immunological protection.[15][16] This secretion gradually became more copious and accrued nutritional complexity over evolutionary time.[11]

History

1959 milk supply in Oberlech, Vorarlberg, Austria

Humans first learned to regularly consume the milk of other mammals following the domestication of animals during the Neolithic Revolution[17] or the invention of agriculture. This development occurred independently in several places around the world from as early as 9000–7000 BC in Southwest Asia[18] to 3500–3000 BC in the Americas.[19] The most important dairy animals—cattle, sheep and goats—were first domesticated in Southwest Asia, although domestic cattle has been independently derived from wild auroch populations several times since.[20][21] 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 4th millennium BC.[22] Sherratt's model is not supported by recent findings, based on the analysis of lipid residue in prehistoric pottery, that show that dairying was practiced in the early phases of agriculture in Southwest Asia, by at least the 7th millennium BC.[23][24]

From Southwest Asia domestic dairy animals spread to Europe (beginning around 7000 BC but not reaching Britain and Scandinavia until after 4000 BC),[25] and South Asia (7000–5500 BC).[26] The first farmers in central Europe[27] and Britain[28] 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 4th millennium BC, and subsequently spread across much of the Eurasian steppe.[29] Sheep and goats were introduced to Africa from Southwest Asia, but African cattle may have been independently domesticated around 7000–6000 BC.[30] Camels, domesticated in central Arabia in the 4th millennium BC, have also been used as a dairy animal in North Africa and the Arabian peninsula.[31] 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 1863, French chemist and biologist Louis Pasteur invented pasteurization, a method of killing harmful bacteria in beverages and food products.[32]

In 1884, Doctor Hervey Thatcher, an American inventor from New York, invented the first glass milk bottle, called 'Thatcher's Common Sense Milk Jar', which was sealed with a waxed paper disk.[32] Later, in 1932, plastic-coated paper milk cartons were introduced commercially as a consequence of their invention by Victor W. Farris.[32]


Sources of milk

All female mammals can by definition produce milk, but cow milk dominates the commercial scence. Human milk is not produced or distributed industrially or commercially; however, milk banks exist that allow for the collection of donated human milk and its redistribution to infants who may benefit from human milk for various reasons (premature neonates, babies with allergies, metabolic diseases, etc.).

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.[5] Other dairy cows in the United States include Ayrshire, Brown Swiss, Guernsey, Jersey, and Milking Shorthorn (Dairy Shorthorn).

Sources aside from cows

Goat milk can be used for other applications such as cheese and other dairy products

Aside from cattle, many kinds of livestock provide milk used by humans for dairy products. These animals include camel, donkey, goat, horse, reindeer, sheep, water buffalo, and yak.

In Russia and Sweden, small moose dairies also exist.[33]

According to the U.S. National Bison Association, American bison (also called American buffalo) are not milked commercially[34]; 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[35] and during the development of commercial Beefalo in the 1970s and 1980s.[36]

Production worldwide

Milk output in 2005
Girl milking a cow by hand

The largest producer of dairy products and milk is India followed by the United States,[37] Germany, and Pakistan.

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 investment 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 farmers.[38] 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.[39]

The table below shows the numbers for water buffalo milk production. Cattle milk is produced in a much wider range.

Top ten buffalo milk producers in 2007[40]
Country Production (tonnes) Note
 India 59,210,000 Unofficial/Semi-official/mirror data
 Pakistan 20,372,000 official figure
 People's Republic of China 2,900,000 FAO estimate
 Egypt 2,300,000
 Nepal 958,603 official figure
 Iran 241,500 FAO estimate
 Myanmar 220,462 official figure
 Italy 200,000 FAO estimate
 Vietnam 32,000
 Turkey 30,375 official figure
 World 86,574,539 Aggregate

Grading

In the United States, there are two grades of milk, with Grade A primarily used for direct sales and consumption in stores, and Grade B used for indirect consumption, such as in cheese making or other processing.

The differences between the two grades are defined in the Wisconsin administrative code for Agriculture, Trade, and Consumer Protection, chapter 60.[41] Grade B generally refers to milk that is cooled in milk cans, which are immersed in a bath of cold flowing water that typically is drawn up from an underground water well rather than using mechanical refrigeration.

  • Grade A farms are inspected every six months, while Grade B farms are inspected every two years {WI-ATCP 60.24.2}
  • Both types of farms are required to have two cleaning vats in the milk house for washing and rinsing of equipment {WI-ATCP 60.07.2(g)}. A farm also must have an additional separate sink and faucet provided for hand washing {WI-ATCP 60.07.2(h)}, unless the bulk tank was installed before Jan 1, 1979, or the farm uses milk cans.
  • Grade A milk stored in a bulk tank is cooled to 45 °F (7 °C) within two hours of milking. Grade A milk in a tank may only rise to 50°F if milk from additional milking sessions is added to the tank (potentially requiring a plate cooler to reduce the temperature of a large volume influx quickly enough) and must be cooled back to 45°F within two hours. {WI-ATCP 60.2.4(b)}
  • Grade B milk in milk cans is cooled to 50 °F (10 °C) within two hours of milking. Grade B farms cannot mix milk into cans from previous milking. {WI-ATCP 60.2.4(c)}
  • The somatic cell count (SCC) of Grade A or B cow or sheep milk may not exceed 750,000 cells per mL, and the SCC of Grade A or B goat milk may not exceed 1,000,000 cells per mL. {WI-ATCP 60.15.4}
  • The bacterial plate or loop count of Grade A milk may not exceed 100,000 per mL, while Grade B milk may not exceed 300,000 per mL. {WI-ATCP 60.15.2}
  • A bacterial plate count test is required at least once a month. {WI-ATCP 60.18.3} If the bacterial count exceeds 100,000 per mL for Grade A or 300,000 per mL for grade B in 3 out of 5 tests, the license to sell milk is suspended. The license will be revoked immediately if the bacterial count ever exceeds 750,000 per mL. {WI-ATCP 60.18.6}

Physical and chemical properties of milk

Milk is an emulsion or colloid of butterfat globules within a water-based fluid that contains dissolved carbohydrates.[42]

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

Butterfat

Each fat globule is surrounded by a membrane consisting of phospholipids and proteins; these emulsifiers keep the individual globules from coalescing and protect the contents of these globules from various enzymes in the fluid portion of the milk. In unhomogenized cow's milk, the fat globules have an average diameter of about four micrometers. The fat-soluble vitamins A, D, E, and K are found within the milk fat portion of the milk.[5]

Other proteins

The largest structures in the fluid portion of the milk are casein protein micelles: aggregates of several thousand protein molecules, bonded with the help of nanometer-scale particles of calcium phosphate. Each micelle is roughly spherical and about a tenth of a micrometer across. There are four different types of casein proteins, and collectively they make up around 80% of the protein in milk, by weight. 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.[5][43]

Milk contains dozens of other types of proteins beside the caseins. They are more water-soluble than the caseins and do not form larger structures. Because these proteins remain suspended in the whey left behind when the caseins coagulate into curds, they are collectively known as whey proteins. Whey proteins make up approximately 20% of the protein in milk, by weight. Lactoglobulin is the most common whey protein by a large margin.[5]

Carbohydrates

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

The carbohydrate 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. In nature, lactose is found only in milk and a small number of plants.[5] 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.[5]

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.[5] 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.[43]

Processing

Milk products and productions relationships (Click for details)

In most Western countries, centralized dairy facilities process milk and products obtained from milk (dairy products), 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 very large nationwide or trans-national corporations (such as Fonterra).

Pasteurization

Pasteurization is used to kill harmful microorganisms by heating the milk for a short time and then cooling it for storage and transportation. Pasteurized milk still is perishable, however, and must be stored cold by both suppliers and consumers. Dairies print expiration dates on each container, after which stores will remove any unsold milk from their shelves. The process destroys the vitamin C content of the raw milk.

A newer process, ultrapasteurization or ultra-high temperature treatment (UHT), heats the milk to a higher temperature for a shorter amount of time. This extends its shelf life and allows the milk to be stored unrefrigerated because of the longer lasting sterilization effect.

Microfiltration

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 whey and is pasteurized in the usual way, but the whey is forced through ceramic microfilters that trap 99.9% of microorganisms in the milk (as compared to 95% killing of microorganisms in conventional pasteurization). The whey then is recombined with the pasteurized cream to reconstitute the original milk composition.

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. In fact, 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.[5] 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.[44] 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.[5] 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.[45] Homogenized milk may be more digestible than unhomogenized milk.[46]

Kurt A. Oster, M.D., who worked during the 1960s through the 1980s, suggested a link between homogenized milk and arterosclerosis, due to damage to plasmalogen resulting from the release of bovine xanthine oxidase (BXO) from the milk fat globular membrane (MFGM) during homogenization. Oster's hypothesis has been widely criticized, however, and has not been generally accepted by the scientific community. No link has been found between arterosclerosis and milk consumption.[46]

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 than may vary.[7] 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 milk contains, on average, 3.4% protein, 3.6% fat, and 4.6% lactose, 0.7% minerals [47] 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.[48][49] High fat content is not unique to aquatic mammals. Guinea pig milk has an average fat content of 46%.[50]

Milk composition analysis, per 100 grams [51][52]
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
Carbohydrate g 4.8 4.4 5.1 4.9
Energy kcal 66 60 95 110
Energy kJ 275 253 396 463
Sugars (lactose) g 4.8 4.4 5.1 4.9
Cholesterol mg 14 10 11 8
Calcium mg 120 100 170 195
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

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%.[5]

Milk fat percentages may be manipulated by dairy farmers' stock diet formulation strategies. Mastitis infection can cause fat levels to decline.[53]

Nutritional value

Cow's milk (whole)
Nutritional value per 100 g (3.5 oz)
Energy 252 kJ (60 kcal)
Carbohydrates 5.26 g
- Sugars 5.26 g
  - Lactose 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
Water 88.32 g
Vitamin A equiv. 28 μg (4%)
Thiamine (vit. B1) 0.044 mg (4%)
Riboflavin (vit. B2) 0.183 mg (15%)
Vitamin B12 0.44 μg (18%)
Vitamin D 40 IU (7%)
Calcium 113 mg (11%)
Magnesium 10 mg (3%)
Potassium 143 mg (3%)
Sodium 43 mg (3%)
100 mL corresponds to 103 g.[54]
Percentages are relative to 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 the age, milk contains 8 grams of protein, and a number of other nutrients (either naturally or through fortification) including:

The amount of calcium from milk that is absorbed by the human body is disputed.[55][56] Calcium from dairy products has a greater bioavailability than calcium from certain vegetables, such as spinach, that contain high levels of calcium-chelating agents,[57] but a similar or lesser bioavailability than calcium from low-oxalate vegetables such as kale, broccoli, or other vegetables in the Brassica genus.[58][59]

Medical research

A 2006 study found that for women desiring to have a child, those who consume full fat dairy products may slightly increase their fertility, while those consuming low-fat dairy products may slightly reduce their fertility.[60]

Numerous studies have found that conjugated linoleic acid, found mainly in milk, meat and dairy products, provides several health benefits including prevention of atherosclerosis, different types of cancer, and hypertension and improved immune function.[61][62][62]

There is recent evidence suggesting consumption of milk is effective at promoting muscle growth[63] and improving post exercise muscle recovery.[64]

In 2010, scientists at the Harvard School of Public Health identified a substance in dairy fat, trans-palmitoleic acid, that may substantially reduce the risk of type 2 diabetes. The researchers examined participants who have been followed for 20 years in an observational study to evaluate risk factors for cardiovascular diseases in older adults. During followup it was found that individuals with higher circulating levels of trans-palmitoleic acid had a much lower risk of developing diabetes, with about a 60% lower risk among participants in the highest quintile (fifth) of trans-palmitoleic acid levels.[65]

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. The production of the enzyme lactase declines significantly after weaning in all mammals. Consequently, many humans become unable to digest lactose properly as they mature. There is a great deal of variance, with some individuals reacting badly to even small amounts of lactose, some able to consume moderate quantities, and some able to consume large quantities of milk and other dairy products without problems. The gene in humans that controls lactase production, and hence lactose tolerance/intolerance, is labeled C/T-13910.[66] An individual who consumes milk without producing sufficient lactase may suffer diarrhea, intestinal gas, cramps and bloating, as the undigested lactose travels through the gastrointestinal tract and serves as nourishment for intestinal microflora who excrete gas, a process known as anaerobic respiration.

It is estimated that 30 to 50 million Americans are lactose intolerant, including 75% of Native Americans and African Americans, and 90% of Asian Americans. Lactose intolerance is less common among those descended from northern Europeans.[67] Other genetic groups that have a lower prevalence of lactose intolerance are the Tuareg of the Sahara, the Fulani of the West African Sahel, and the Beja and Kabbabish of Sudan, as well as possibly the Tutsi population of the Uganda-Rwanda area.[68] Another locus of lactose tolerance is in Northern India.[66]

Lactose intolerance is a natural process and there is no reliable way to prevent or reverse it.

Controversy

Some studies suggest that milk consumption may increase the risk of suffering from certain health problems. Cow milk allergy (CMA) is an immunologically mediated adverse reaction to one or more cow's milk proteins. Rarely is it severe enough to cause death.[69]

Milk contains casein, a substance that breaks down in the human stomach to produce casomorphin, an opioid peptide. In the early 1990s it was hypothesized that casomorphin can cause or aggravate autism spectrum disorders,[70][71] and casein-free diets are widely promoted. Studies supporting these claims have had significant flaws, and the data are inadequate to guide autism treatment recommendations.[71]

A study demonstrated that men who drink a large amount of milk and consume dairy products were at a slightly increased risk of developing Parkinson's disease; the effect for women was smaller.[72] The reason behind this is not fully understood, and it also remains unclear why there is less of a risk for women.[72][73] Several sources suggest a correlation between high calcium intake (2000 mg per day, or twice the US recommended daily allowance, equivalent to six or more glasses of milk per day) and prostate cancer.[74] A large study specifically implicates dairy, i.e., low-fat milk and other dairy to which vitamin A palmitate has been added.[75][76]

A review published by the World Cancer Research Fund and the American Institute for Cancer Research states that at least eleven human population studies have linked excessive dairy product consumption and prostate cancer.[77][78]

Medical studies also have shown a possible link between milk consumption and the exacerbation of diseases such as Crohn's disease,[79] Hirschsprung's disease–mimicking symptoms in babies with existing cow's milk allergies,[80] and the aggravation of Behçet's disease.[81]

Bovine growth hormone supplementation

Since November 1993, with FDA approval,[82] Monsanto has been selling recombinant bovine somatotropin (rbST), also called rBGH, to dairy farmers. Cows produce bovine growth hormone naturally, but some producers administer an additional recombinant version of BGH which is produced through a genetically engineered E. coli because it increases milk production. Bovine growth hormone also stimulates liver production of insulin-like growth factor 1 (IGF1). Monsanto has stated that both of these compounds are harmless given the levels found in milk and the effects of pasteurization,[83] however, Monsanto's own tests, conducted in 1987, demonstrated that statistically significant growth stimulating effects were induced in organs of adult rats by feeding IGF-1 at low dose levels for only two weeks. "Drinking rBGH milk would thus be expected to significantly increase IGF-1 blood levels and consequently to increase risks of developing breast cancer and promoting its invasiveness."[84]

On June 9, 2006, the largest milk processor in the world and the two largest supermarkets in the United States--Dean Foods, Wal-Mart, and Kroger--announced that they are "on a nationwide search for rBGH-free milk."[85] 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.[86] 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.[87] 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.[88][89]

In the European Union, rBGH is banned.[90]

Ethical concerns

Vegans and some other vegetarians do not consume milk for a variety of reasons. They may object to features of dairy farming including the necessity of killing 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.[91]

Flavored milk in US schools

According to an article in The New York Times, 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 US offer rice or soy milk and almost 17% of all U.S. school districts offer lactose-free milk. Seventy-one percent of the milk served in the U.S. is flavored, causing some school districts to propose a ban because flavored milk has added sugars. The Boulder, Colorado school district banned flavored milk in 2009 and instead installed a dispenser that keeps the milk colder.[92]

Varieties and brands

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

  • additives (e.g., vitamins),
  • age (e.g., cheddar),
  • coagulation (e.g., cottage cheese),
  • farming method (e.g., organic, grass-fed).
  • fat content (e.g., half and half),
  • fermentation (e.g., buttermilk),
  • flavoring (e.g., chocolate),
  • homogenization (e.g., cream top),
  • reduction or elimination of lactose,
  • mammal (e.g., cow, goat, sheep),
  • packaging (e.g., bottle),
  • pasteurization (e.g., raw milk),
  • water content (e.g., dry milk)

Milk preserved by the UHT process does not need to be refrigerated before opening and has a longer shelf life than milk in ordinary packaging. It is typically sold unrefrigerated in the U.K., 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,[93] has had "HYLA" (acronym for hydrolysed lactose) products available for many years. Lactose of low-lactose level cow's milk products, ranging from ice cream to cheese, is enzymatically hydrolysed 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,[94] and the US, where the company says ultrafiltration is used.[95]

In the U.K., where an estimated 15% of the population are affected by lactose intolerance,[citation needed] 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 ("a/B milk") is available in some areas.[96] 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.[97]

Alternatively, a bacterium such as L. acidophilus may be added, which affects the lactose in milk the same way it affects the lactose in yogurt.

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.[98]

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.[99]

Distribution

Reusable glass milk bottles used for home delivery service in the UK
A glass milk bottle from the U.S. Note that 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 rack.

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 "metrification", milk was generally distributed in 1 pint (568ml) glass bottles. In Australia and in 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 were concerned that the replacement of the pint bottles with 500ml bottles would result in a 13.6% drop in milk consumption; hence, all pint bottles were recalled and replaced by 600ml 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.[100] Milk is now available in a variety of sizes in cardboard 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 flavoured milks – for example, as mentioned above, Farmers Union Iced Coffee outsells Coca-Cola in South Australia.

India

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

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 aluminium foil tops directly to households, has almost disappeared. The main reasons for the decline of U.K. home deliveries by milkmen are household refrigerators (which lessen the need for daily milk deliveries) and private car usage (which has increased supermarket shopping). 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.[101] By 2010, the estimated number of milkmen had dropped to 6,000.[102] 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 U.K. households (6.7 billion liters in 2008/2009).[103]

Almost 95% of all milk in the U.K. 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 U.K. 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 .5 US pints (0.24 l) 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:

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.[100]
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.
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.
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.
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.
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.
Sizes of 500 mL, 1 liter (the most common), 1.5 liters, 2 liters and 3 liters are commonplace.
Commonly sold in 1 L or 1.5 L cartons, in some places also in 2 dl and 5 dl cartons.
Milk is sold in glass bottles (220 mL), cartons (236 mL and 1 L), plastic jugs (2 liters) and aseptic cartons (250 mL).
Commonly sold in 500 mL plastic bags and in bottles in some parts like in 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 different sizes, usually in aseptic cartons.
Usually sold in 1 liter cartons, but smaller, snack-sized cartons are available.
Non-UHT milk is most commonly sold in 1 liter waxed cardboard boxes and 1 liter plastic bags. It may also be found in 0.5 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 0.25 L) carton "bricks".
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.
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).
Milk is supplied in 500 mL Plastic bags and carried in Jugs from rural to cities and sell
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.
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.
Commonly sold in 0.3 L, 1 L or 1.5 L cartons and sometimes as plastic or glass milk bottles.
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.
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.
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 Wal-Mart stores.[104]
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.

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

Brazilian Yakult is a probiotic milk-like product made by fermenting a mixture of skimmed milk with a special strain of the bacterium Lactobacillus casei Shirota.

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, yoghurt, 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,[citation needed] 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 degrees Celsius 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.

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". In ancient Greek mythology, the goddess Hera spilled her breast milk after refusing to feed Heracles, resulting in the Milky Way.

In African and Asian developing nations, 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.[105]

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 Ramadhan fast is traditionally broken with a glass of milk and dates.

To milk someone, in the vernacular of many English-speaking countries, is to take advantage of the person.

The word "milk" has had many slang meanings over time. In the early 17th century the word was used to mean semen, or vaginal secretions, or to masturbate oneself or someone else. In the 19th century, milk was used to describe a cheap alcoholic drink made from methylated spirits 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 meaning to siphon gas from a car.[106]

Milk is sometimes referred to as moo juice in American English,[107] while Cockney rhyming slang calls it Acker Bilk, Tom Silk, Lady in silk and Kilroy Silk.[108]

The name of the Russian Molokan (Russian: "Молока́не") religion in Russian is derived from Russian "Молоко́ " meaning "Milk" as they would drink milk on the Russian Orthodox days of fast.

Other uses

A glass of milk

Besides serving as a beverage or source of food, milk has been described as used by farmers and gardeners as an organic fungicide and foliage fertilizer.[109][unreliable source?] 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.[110]

See also

References

  1. ^ William H. Bowen and Ruth A. Lawrence, Comparison of the Cariogenicity of Cola, Honey, Cattle Milk, Human Milk, and Sucrose, PEDIATRICS Vol. 116 No. 4 October 2005, pp. 921–926. pediatrics.aappublications.org. Retrieved on 21 July 2009.
  2. ^ Soil pH: What it Means, SUNY College of Environmental Science and Forestry. www.esf.edu. Retrieved on 21 July 2009.
  3. ^ Basnet, S.; Schneider, M.; Gazit, A.; Mander, G.; Doctor, A. (April 2010). "Fresh Goat's Milk for Infants: Myths and Realities—A Review". Pediatrics 125 (4): e973–977. doi:10.1542/peds.2009-1906. PMID 20231186. 
  4. ^ Champe, Pamela (2008). "Introduction to Carbohydrates". Lippincott's Illustrated Reviews: Biochemistry, 4th ed.. Baltimore: Lippincott Williams & Wilkins. p. 88. ISBN 9780781769600. 
  5. ^ a b c d e f g h i j k McGee, Harold (2004) [1984]. "Milk and Dairy Products". On Food and Cooking: The Science and Lore of the Kitchen (2nd ed.). New York: Scribner. pp. 7–67. ISBN 978-0684800011. http://books.google.com/books?id=bKVCtH4AjwgC&lpg=PP1&pg=PA7#v=onepage&q=lactase&f=false. 
  6. ^ "World's No 1 Milk Producer". Indiadairy.com. http://www.indiadairy.com/ind_world_number_one_milk_producer.html. Retrieved 2010-08-28. 
  7. ^ a b Goff, Douglas (2010). "Introduction to Dairy Science and Technology: Milk History, Consumption, Production, and Composition". Dairy Science and Technology. University of Guelph. http://www.foodsci.uoguelph.ca/dairyedu/intro.html. Retrieved 8 February 2011. 
  8. ^ Wayne Arnold, "A Thirst for Milk Bred by New Wealth Sends Prices Soaring", The New York Times September 4, 2007.
  9. ^ Bewley, Elizabeth (24 June 2010). "Dairy farmers tackle big coops". Burlington, Vermont: Burlington Free Press. pp. 8B. 
  10. ^ Gussekloo, S.W.S. (2006). "Chapter 2: Feeding Structures in Birds". In Bels, V. Feeding in Domestic Vertebrates: From Structure to Behaviour. CABI Publishing. p. 22. ISBN 978-1-84593-063-9. "A remarkable adaptation can be found in the crop of pigeons. During the breeding season the crop produces a yellow-white fat-rich secretion known as crop milk that is used to feed the nestlings. … The crop milk resembles strongly the milk produced by mammals, except for the fact that carbohydrates and calcium are missing in crop milk." 
  11. ^ a b c Oftedal, Olav T. (2002). "The mammary gland and its origin during synapsid evolution". Journal of Mammary Gland Biology and Neoplasia 7 (3): 225–252. doi:10.1023/A:1022896515287. PMID 12751889. 
  12. ^ Oftedal, Olav T. (2002). "The origin of lactation as a water source for parchment-shelled eggs.". Journal of Mammary Gland Biology and Neoplasia 7 (3): 253–66. doi:10.1023/A:1022848632125. PMID 12751890. 
  13. ^ "Lactating on Eggs". Nationalzoo.si.edu. 2003-07-14. http://nationalzoo.si.edu/ConservationAndScience/SpotlightOnScience/oftedalolav20030714.cfm. Retrieved 2009-03-08. 
  14. ^ Lefèvre C.M., Sharp J.A., Nicholas K.R. (2010). "Evolution of lactation: ancient origin and extreme adaptations of the lactation system". Annual Review of Genomics and Human Genetics (11): 219–238. 
  15. ^ Vorbach C., Capecchi M.R., Penninger J.M. (2006). "Evolution of the mammary gland from the innate immune system?". Bioessays 28: 606–616. doi:10.1002/bies.20423. PMID 16700061. 
  16. ^ Goldman A.S. (2002). "Evolution of the mammary gland defense system and the ontogeny of the immune system". Journal of Mammary Gland Biology and Neoplasia (7): 277–289. 
  17. ^ referring to the Neolithic period in Eurasian prehistory)
  18. ^ Bellwood, Peter (2005). "The Beginnings of Agriculture in Southwest Asia". First Farmers: the origins of agricultural societies. Malden, MA: Blackwell Publushing. pp. 44–68. ISBN 978-0-631-20566-1. 
  19. ^ Bellwood, Peter (2005). "Early Agriculture in the Americas". First Farmers: the origins of agricultural societies. Malden, MA: Blackwell Publushing. pp. 146–179. ISBN 978-0-631-20566-1. 
  20. ^ Beja-Pereira, A.; Caramelli, D.; Lalueza-Fox, C.; Vernesi, C.; Ferrand, N.; Casoli, A.; Goyache, F.; Royo, L. J. et al. (2006). "The origin of European cattle: Evidence from modern and ancient DNA". Proceedings of the National Academy of Sciences 103 (21): 8113–8118. doi:10.1073/pnas.0509210103.  edit
  21. ^ Avetrani, P.; Folgiero, V.; Bon, G.; Di Carlo, S. E.; Fabi, A.; Nisticò, C.; Vici, P.; Melucci, E. et al. (2008). Jin, Dong-Yan. ed. "Induction of ErbB-3 Expression by α6β4 Integrin Contributes to Tamoxifen Resistance in ERβ1-Negative Breast Carcinomas". PLoS ONE 3 (2): e1592. doi:10.1371/journal.pone.0001592. PMC 2220038. PMID 18270579. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2220038. 
  22. ^ Sherratt, Andrew (1981). "Plough and pastoralism: aspects of the secondary products revolution". In Hodder, I.; Isaac, G.; Hammond, N.. Pattern of the Past: Studies in honour of David Clarke. Cambridge: Cambridge University Press. pp. 261–305. ISBN 0521227631. 
  23. ^ Vigne, D.; Helmer, J.-D. (2007). "Was milk a "secondary product" in the Old World Neolithisation process? Its role in the domestication of cattle, sheep and goats". Anthropozoologica 42 (2): 9–40. http://www.mnhn.fr/museum/front/medias/publication/12514_009_040.pdf. 
  24. ^ Evershed, R. P.; Payne, S.; Sherratt, A. G.; Copley, M. S.; Coolidge, J.; Urem-Kotsu, D.; Kotsakis, K.; Özdoğan, M. et al. (2008). "Earliest date for milk use in the Near East and southeastern Europe linked to cattle herding". Nature 455 (7212): 528–531. doi:10.1038/nature07180. PMID 18690215.  edit
  25. ^ Price, T. D. (2000). "Europe's first farmers: an introduction". In T. D. Price. Europe's First Farmers. Cambridge: Cambridge University Press. pp. 1–18. ISBN 0521662036. 
  26. ^ Meadow, R. H. (1996). "The origins and spread of agriculture and pastoralism in northwestern South Asia". In D. R. Harris. The origins and spread of agriculture and pastoralism in Eurasia. London: UCL Press. pp. 390–412. ISBN 1857285387. 
  27. ^ Craig, Oliver E.; John Chapman, Carl Heron, Laura H. Willis, László Bartosiewicz, Gillian Taylor, Alasdair Whittle and Matthew Collins (2005). "Did the first farmers of central and eastern Europe produce dairy foods?". Antiquity 79 (306): 882–894. http://antiquity.ac.uk/ant/079/ant0790882.htm. 
  28. ^ Copley, M. S.; Berstan, R.; Mukherjee, A. J.; Dudd, S. N.; Straker, V.; Payne, S.; Evershed, R. P. (2005). "Dairying in antiquity. III. Evidence from absorbed lipid residues dating to the British Neolithic". Journal of Archaeological Science 32 (4): 523–546. doi:10.1016/j.jas.2004.08.006.  edit
  29. ^ Anthony, D. W. (2007). The Horse, the Wheel, and Language. Princeton, NJ: Princeton University Press. ISBN 978-0691058870. 
  30. ^ Gifford-Gonzalez, D. (2004). "Pastoralism and its Consequences". In A. B. Stahl. African archaeology: a critical introduction. Malden, MA: Blackwell Publishing. pp. 187–224. ISBN 9781405101554. 
  31. ^ Peters, J. (1997). "The dromedary: Ancestry, history of domestication and medical treatment in early historic times". Tierarztliche Praxis. Ausgabe G, Grosstiere/Nutztiere 25 (6): 559–565. PMID 9451759.  edit
  32. ^ a b c "The History Of Milk", About.com. Retrieved 13-8-2010.
  33. ^ "Moose milk makes for unusual cheese". The Globe and Mail. 26 June 2004. Archived from the original on September 30, 2007. http://web.archive.org/web/20070930035220/http://www.theglobeandmail.com/servlet/ArticleNews/TPStory/LAC/20040626/MOOSE26/TPEntertainment/Style. Retrieved 2007-08-27. 
  34. ^ "About Bison: Frequently Asked Questions". National Bison Association. http://www.bisoncentral.com/index.php?c=63&d=73&a=1022&w=2&r=Y. Retrieved 2009-08-16. 
  35. ^ Allen, Joel Asaph (June 1877). "Part II., Chapter 4. Domestication of the Buffalo". In Elliott Coues, Secretary of the Survey. History of the American Bison: bison americanus. extracted from the 9th Annual Report of the United States Geological Survey (1875). Washington, DC: Department of the Interior, United States Geological Survey, Government Printing Office. pp. 585–586. OCLC 991639. http://books.google.com/?id=oj04AAAAMAAJ&pg=PA585&lpg=PA585&dq=milking+bison&q=milking%20bison. Retrieved August 16, 2009. 
  36. ^ O'Connor, George (March/April 1981). "The Basics of Beefalo Raising". Mother Earth News (Ogden Publications) (68). http://www.motherearthnews.com/Sustainable-Farming/1981-03-01/The-Basics-of-Beefalo-Raising.aspx. Retrieved 8 February 2011. 
  37. ^ International dairy product prices are turning down: how far, how fast?, FAO Food outlook No.1, June 2006. www.fao.org. Retrieved on 21 July 2009.
  38. ^ J. Henriksen, "Milk for Health and Wealth". FAO Diversification Booklet Series 6, Rome
  39. ^ O.P. Sinha, "Dairy in India", FAO, Rome
  40. ^ Livestock Production statistics, FAOSTAT, Food And Agricultural Organization of the United Nations. faostat.fao.org. Retrieved on 21 July 2009.
  41. ^ Wisconsin administrative code for Agriculture, Trade, and Consumer Protection, Chapter ATCP 60
  42. ^ Rolf Jost "Milk and Dairy Products" Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2002. doi:10.1002/14356007.a16_589.pub3
  43. ^ a b Goff, Douglas (2010). "Dairy Chemistry and Physics". Dairy Science and Technology. University of Guelph. http://www.foodsci.uoguelph.ca/dairyedu/chem.html. Retrieved 8 February 2011. 
  44. ^ Goff, Douglas (2010). "Homogenization of Milk and Milk Products". Dairy Science and Technology. University of Guelph. http://www.foodsci.uoguelph.ca/dairyedu/homogenization.html. Retrieved 8 February 2011. 
  45. ^ "Research Can Lead To Longer Shelf Life For Dairy Products". Sciencedaily.com. 2002-12-23. http://www.sciencedaily.com/releases/2002/12/021223084204.htm. Retrieved 2010-08-28. 
  46. ^ a b "Does homogenization affect the human health properties of cow’s milk?"
  47. ^ "Milk contains traces of ash". Chennai, India: Hindu.com. 2008-07-10. http://www.hindu.com/seta/2008/07/10/stories/2008071050201800.htm. Retrieved 2010-08-28. 
  48. ^ "Milk From Cows and Other Animals, web page by Washington Dairy Products Commission". Havemilk.com. http://www.havemilk.com/article.asp?id=1485#contentbyspecies. Retrieved 2010-08-28. 
  49. ^ "Whale". Whale. Encarta. http://www.webcitation.org/5kx5gN68d. 
  50. ^ Morales, Edmundo (1995). The Guinea Pig : Healing, Food, and Ritual in the Andes. University of Arizona Press. ISBN 0-8165-1558-1. 
  51. ^ "Milk analysis". North Wales Buffalo. Archived from the original on 2007-09-29. http://web.archive.org/web/20070929071651/http://www.northwalesbuffalo.co.uk/milk_analysis.htm. Retrieved 3 August 2009.  (Citing McCane, Widdowson, Scherz, Kloos, International Laboratory Services.)
  52. ^ USDA National Nutrient Database for Standard Reference
  53. ^ Designing Foods: Animal Product Options in the Marketplace. National Academies Press. 1988. ISBN 9780309037952. http://books.google.com/?id=qJgdAEhQvnMC&pg=PA226. 
  54. ^ Jones, Alicia Noelle (2002). "Density of Milk". The Physics Factbook. http://hypertextbook.com/facts/2002/AliciaNoelleJones.shtml. 
  55. ^ "Calcium Rich Foods: Get All The Calcium You Need Without Milk". Thehealthierlife.co.uk. 2010-02-08. http://www.thehealthierlife.co.uk/article/3097/calcium-rich-foods.html. Retrieved 2010-08-28. 
  56. ^ Feskanich D, Willett WC, Stampfer MJ, Colditz GA. Milk, dietary calcium, and bone fractures in women: a 12-year prospective study. Am J Public Health 1997; 87:992-7.
  57. ^ Brody T. Calcium and phosphate. In: Nutritional biochemistry. 2nd ed. Boston: Academic Press, 1999:761–94
  58. ^ Heaney, Robert P.; Weaver, Connie M. (1990). "Calcium absorption from kale". The American journal of clinical nutrition 51 (4): 656–7. PMID 2321572. http://www.ajcn.org/cgi/pmidlookup?view=long&pmid=2321572. 
  59. ^ "Calcium and Milk: What's Best for Your Bones and Health?". The Nutrition Source. Harvard School of Public Health. 2011. http://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/calcium-full-story/index.html. Retrieved 8 February 2011. 
  60. ^ Chavarro JE, Rich-Edwards JW, Rosner B, Willett WC (May 2007). "A prospective study of dairy foods intake and anovulatory infertility". Human Reproduction 22 (5): 1340–7. doi:10.1093/humrep/dem019. PMID 17329264. 
  61. ^ Lp, Clement; Scimeca, Joseph A.; Thompson, Henry J. (1994). "Conjugated linoleic acid. A powerful anticarcinogen from animal fat sources". Cancer 74 (3 Suppl): 1050–4. doi:10.1002/1097-0142(19940801)74:3+<1050::AID-CNCR2820741512>3.0.CO;2-I. PMID 8039138. 
  62. ^ a b Kritchevsky, D (2000). "Antimutagenic and some other effects of conjugated linoleic acid". The British journal of nutrition 83 (5): 459–65. PMID 10953669. 
  63. ^ Roy BD (2008). "Milk: the new sports drink? A Review". J Int Soc Sports Nutr 5: 15. doi:10.1186/1550-2783-5-15. PMC 2569005. PMID 18831752. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2569005. 
  64. ^ Ferguson-Stegall et al (2010). "Effects of Chocolate Milk Supplementation on Recovery from Cycling Exercise and Subsequent Time Trial Performance". International Journal of Exercise Science: Conference Abstract Submissions 2 (2). http://digitalcommons.wku.edu/ijesab/vol2/iss2/25. 
  65. ^ Component in common dairy foods may cut diabetes risk, study suggests. Sciencedaily.com (2010-12-23). Retrieved on 2011-01-14.
  66. ^ a b Babu, J. et al "Frequency of lactose malabsorption among healthy southern and northern Indian populations", American Journal of Clinical Nutrition, doi 10.3945/ajcn.2009.27946
  67. ^ University of Maryland Medical Center. "Digestive Disorders – Lactose Intolerance". http://www.umm.edu/digest/lactose.htm. Retrieved 2009-05-03. 
  68. ^ Patterson, K. D. "Lactose Tolerance", The Cambridge World History of Food, Kiple, K.F. ed. Cambridge University Press, 2000 http://www.cambridge.org/us/books/kiple/lactose.htm
  69. ^ Høst A (1994). "Cow's milk protein allergy and intolerance in infancy. Some clinical, epidemiological and immunological aspects". Pediatric Allergy and Immunology 5 (5 Suppl): 1–36. PMID 7704117. 
  70. ^ Reichelt KL, Knivsberg A-M, Lind G, Nødland M (1991). "Probable etiology and possible treatment of childhood autism". Brain Dysfunct 4: 308–19. 
  71. ^ a b Christison GW, Ivany K (2006). "Elimination diets in autism spectrum disorders: any wheat amidst the chaff?". J Dev Behav Pediatr 27 (2 Suppl 2): S162. doi:10.1097/00004703-200604002-00015. PMID 16685183. 
  72. ^ a b H. Chen et al., Consumption of Dairy Products and Risk of Parkinson's Disease, American Journal of Epidemiology. 2007 May;165(9):998–1006
  73. ^ "Milk linked to Parkinson's risk". BBC News. 7 April 2005. http://news.bbc.co.uk/1/hi/health/4419477.stm. Retrieved 10 April 2010. 
  74. ^ Giovannucci E, Rimm EB, Wolk A, et al. (February 1998). "Calcium and fructose intake in relation to risk of prostate cancer". Cancer Research 58 (3): 442–7. PMID 9458087. http://cancerres.aacrjournals.org/cgi/pmidlookup?view=long&pmid=9458087. 
  75. ^ "Low fat milk causes prostate cancer on Yedda". Yedda.com. 2008-01-03. http://yedda.com/questions/Low_fat_milk_causes_prostate_cancer_7351021963170/. Retrieved 2010-08-28. 
  76. ^ Chan JM, Stampfer MJ, Ma J, Gann PH, Gaziano JM, Giovannucci EL (October 2001). "Dairy products, calcium, and prostate cancer risk in the Physicians' Health Study". The American Journal of Clinical Nutrition 74 (4): 549–54. PMID 11566656. http://www.ajcn.org/cgi/pmidlookup?view=long&pmid=11566656. 
  77. ^ The World Cancer Research Fund and American Institute for Cancer Research (1997). "Food, nutrition and the prevention of cancer: a global perspective". Food, nutrition and the prevention of cancer: a global perspective. 
  78. ^ Chan JM et al. (2005). "Role of diet in prostate cancer development and progression". J Clin Oncol 23 (32): 8152–60. doi:10.1200/JCO.2005.03.1492. PMID 16278466. 
  79. ^ "How Bacteria In Cows' (sic) Milk May Cause Crohn's Disease". Sciencedaily.com. 2007-12-13. http://www.sciencedaily.com/releases/2007/12/071210104002.htm. Retrieved 2010-08-28. 
  80. ^ Cow's milk protein allergy presenting with Hirschsprung's disease–mimicking symptoms.
  81. ^ "Humoral and cell mediated immune response to cow's milk proteins in Behçet's disease". Ard.bmj.com. http://ard.bmj.com/cgi/content/abstract/61/5/459. Retrieved 2010-08-28. 
  82. ^ Report on the Food and Drug Administration's Review of the Safety of Recombinant Bovine Somatotropin
  83. ^ Institute of Food Science & Technology (1999-09-01). "Bovine somatotropin (bST)". Monsanto. Archived from the original on November 26, 2007. http://web.archive.org/web/20071126054847/http://www.monsantodairy.com/about/human_safety/ifst_rbst1.html. Retrieved 2008-01-16. 
  84. ^ "Monsanto's Hormonal Milk Poses Serious Risks of Breast Cancer, Besides Other Cancers, Warns Professor of Environmental Medicine at the University of Illinois School of Public Health". Preventcancer.com. 1998-06-21. http://www.preventcancer.com/press/releases/july8_98.htm. Retrieved 2010-08-28. 
  85. ^ "Oca News Articles". Organicconsumers.org. http://www.organicconsumers.org/2006/article_747.cfm. Retrieved 2010-08-28. 
  86. ^ Voluntary Labeling of Milk and Milk Products From Cows That Have Not Been Treated With Recombinant Bovine Somatotropin
  87. ^ Epstein, Samuel S.. "Milk: America’s Health Problem". Cancer Prevention Coalition. http://www.preventcancer.com/consumers/general/milk.htm. Retrieved 2010-08-28. 
  88. ^ "Mastitis Control Programs: Milk Quality Evaluation Tools for Dairy Farmers". Ag.ndsu.edu. 1997-01-01. http://www.ag.ndsu.edu/pubs/ansci/dairy/as1131w.htm. Retrieved 2010-08-28. 
  89. ^ Greger, Michael (January 2001). "Paratuberculosis and Crohn's Disease: Got Milk?". Vegan Outreach. http://www.veganoutreach.org/health/greger-gotmilk.pdf. Retrieved 8 February 2011. 
  90. ^ "European Council Decision of December 17, 1999". Eur-lex.europa.eu. http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:31999D0879:EN:HTML. Retrieved 2010-08-28. 
  91. ^ People for the Ethical Treatment of Animals. "Milk Sucks". http://www.milksucks.com/index2.asp. Retrieved 2009-12-09. 
  92. ^ Severson, Kim (2010-08-24). "A School Fight Over Chocolate Milk". The New York Times. http://www.nytimes.com/2010/08/25/dining/25Milk.html. 
  93. ^ Sahi, T (1974). "Lactose malabsorption in Finnish-speaking and Swedish-speaking populations in Finland". Scandinavian journal of gastroenterology 9 (3): 303–8. PMID 4852638. 
  94. ^ http://www.zerolactose.be
  95. ^ http://www.realgoodness.com/lactose-free-technology.cfm
  96. ^ "Yogurt and Other Cultured Dairy Products", National Dairy Council, 2000.
  97. ^ Rombauer, Irma S. and Marion Rombauer Becker (1975). The Joy of Cooking (Revised Edition). Bobbs Merrill. p. 533. ISBN 0-672-51831-7. 
  98. ^ "How to Buy Dairy Products", Home and Garden Bulletin 255, USDA, February 1995. Retrieved 16 May 2007.
  99. ^ "flavored milk and school lunch programs | Chocolate Milk Debate Rages On | Rodale News". Rodale.com. http://www.rodale.com/flavored-milk-and-school-lunch-programs. Retrieved 2010-08-28. 
  100. ^ a b Milk and Juice Cartons Fact Sheet, Waste Wise WA, zerowastewa.com.au. Retrieved on 21 June 2009.
  101. ^ Coughlan, Sean (2006-03-28). "Milk's online top-up". BBC News. http://news.bbc.co.uk/1/hi/magazine/4850336.stm. Retrieved 2010-08-28. 
  102. ^ "Find me a Milkman – I want doorstep deliveries!". Dairy UK. http://www.dairyuk.org/for-consumers-mainmenu-278/find-me-a-milkman-mainmenu-290. Retrieved 8 February 2011. 
  103. ^ ""Milk product roadmaps", The Department for Environment, Food and Rural Affairs". Defra.gov.uk. http://www.defra.gov.uk/environment/business/products/roadmaps/milk.htm. Retrieved 2010-08-28. 
  104. ^ Rosenbloom, Stephanie (2008-06-30). "Solution, or Mess? A Milk Jug for a Green Earth". The New York Times. http://www.nytimes.com/2008/06/30/business/30milk.html?ex=1372564800&en=4b8e1de115184001&ei=5124&partner=permalink&exprod=permalink. 
  105. ^ Crawford et al., part B, section III, ch. 1: Butter. Retrieved 28 November 2005.
  106. ^ Jonathon Green (2005). Cassell's Dictionary of Slang. Weidenfeld & Nicholson. ISBN 9780304366361. http://books.google.com/?id=5GpLcC4a5fAC&pg=PA943. 
  107. ^ "Milk, Moo Juice And American English". Stevens-bolton.co.uk. http://www.stevens-bolton.co.uk/FileServer.aspx?oID=514. Retrieved 2010-08-28. 
  108. ^ "Cockney Rhyming Slang". Cockney Rhyming Slang. http://www.cockneyrhymingslang.co.uk/english/alternatives/295. Retrieved 2010-08-28. 
  109. ^ Campbell, Malcom (2003-09-19). "Fact Sheet: Milk Fungicide". Australian Broadcasting Corporation. http://www.abc.net.au/gardening/stories/s948323.htm. Retrieved 2009-04-01. 
  110. ^ "Drop of white the right stuff for vines". Science Daily. 2002-09-12. http://www.sciencedaily.com/releases/2002/09/020912071438.htm. Retrieved 2009-04-01. 

Bibliography

External links


Wikimedia Foundation. 2010.

Игры ⚽ Нужен реферат?

Look at other dictionaries:

  • Milk — (m[i^]lk), n. [AS. meoluc, meoloc, meolc, milc; akin to OFries. meloc, D. melk, G. milch, OHG. miluh, Icel. mj[=o]lk, Sw. mj[ o]lk, Dan. melk, Goth. miluks, G. melken to milk, OHG. melchan, Lith. milszti, L. mulgere, Gr. ame lgein. [root]107. Cf …   The Collaborative International Dictionary of English

  • Milk — Saltar a navegación, búsqueda Milk Título Milk Mi nombre es Harvey Milk (España) Ficha técnica …   Wikipedia Español

  • Milk Em' — Single by Ghostface Killah Trife da God from the album Put It on the Line …   Wikipedia

  • milk — milk; milk·en; milk·er; milk·i·ly; milk·i·ness; milk·less; milk·man; milk·ness; milk·sop; milk·sop·ping; milk·sop·py; pre·milk; …   English syllables

  • milk — [milk] n. [ME < OE meolc, akin to ON mjolk, Ger milch < IE base * melĝ , to stroke, press out, wipe off, hence to milk (an animal) > Gr amelgein, L mulgere, to milk] 1. a white or yellowish emulsion secreted by the mammary glands of… …   English World dictionary

  • Milk — (m[i^]lk), v. t. [imp. & p. p. {Milked} (m[i^]lkt); p. pr. & vb. n. {Milking}.] [1913 Webster] 1. To draw or press milk from the breasts or udder of, by the hand or mouth; to withdraw the milk of. Milking the kine. Gay. [1913 Webster] I have… …   The Collaborative International Dictionary of English

  • milk — ► NOUN 1) an opaque white fluid produced by female mammals for the nourishment of their young. 2) the milk of cows as a food and drink for humans. 3) the milk like juice of certain plants, such as the coconut. ► VERB 1) draw milk from (a cow or… …   English terms dictionary

  • Milk Me — Studio album by The Beatnuts Released August 30, 2004 (UK) August 31, 2004 …   Wikipedia

  • Milk — steht für: Milk (Film), einen Film über Harvey Milk Milk!, eine ehemalige Diskothek in Mannheim Milk Inc., eine belgische Band Milk River, den Namen verschiedener Flüsse und Orte Milk ist der Familienname folgender Personen: Chris Milk, US… …   Deutsch Wikipedia

  • Milk it — est la 8e chanson de l album In Utero du groupe Nirvana et dure 3 min 54. Milk it est un morceau représentatif de ce à quoi le grand public s attendait après avoir entendu dire que les patrons de Geffen trouvaient In Utero violemment inaudible.… …   Wikipédia en Français

  • milk — [mɪlk] verb [transitive] informal to get as much as you can from someone or from a situation, in a very determined and sometimes dishonest way: milk somebody/​something for something • The cable companies will be able to milk subscribers for even …   Financial and business terms

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”