A glass of cow's milk.

A goat kid feeding on its mother's milk.

Milk is a white liquid produced by the mammary glands of female mammals (including monotremes). The female ability to produce milk is one of the defining characteristics of mammals. It provides the primary source of nutrition for newborns before they are able to digest other types of food. The early lactation milk is known as colostrum, and carries the mother's antibodies to the baby. It can reduce the risk of many diseases in the baby. Image File history File links Download high resolution version (600x800, 23 KB) A glass of milk - From de:Bild:Milch. ... Image File history File links Download high resolution version (600x800, 23 KB) A glass of milk - From de:Bild:Milch. ... COW is an acronym for a number of things: Can of worms The COW programming language, an esoteric programming language. ... Image File history File links Download high-resolution version (1600x1067, 539 KB) A domestic goat kid feeding on its mothers milk. ... Image File history File links Download high-resolution version (1600x1067, 539 KB) A domestic goat kid feeding on its mothers milk. ... Mammary glands are the organs that, in the female mammal, produce milk for the sustenance of the young. ... Subclasses Subclass Allotheria* Order Docodonta (extinct) Order Multituberculata (extinct) Order Palaeoryctoides (extinct) Order Triconodonta (extinct) Order Volaticotheria (extinct) Subclass Prototheria Order Monotremata Subclass Theria Infraclass Trituberculata (extinct) Infraclass Metatheria Infraclass Eutheria Mammals are a class of vertebrate animals characterized by the production of milk in females for the nourishment of... Families †Kollikodontidae Ornithorhynchidae - Platypus Tachyglossidae - Echidnas †Steropodontidae Monotremes (monos, single + trema, hole; refers to the cloaca) are mammals that lay eggs instead of giving birth to live young like marsupials (Metatheria) and placental mammals (Eutheria). ... A human infant In basic English usage, an infant is defined as a child at the youngest stage of life, especially before they can walk or simply a child before the age of one. ... This article or section does not cite any references or sources. ... Kittens nursing Lactation describes the secretion of milk from the mammary glands, the process of providing that milk to the young, and the period of time that a mother lactates to feed her young. ... Colostrum (also known as beestings or first milk) is a form of milk produced by the mammary glands in late pregnancy and the few days after giving birth. ... Each antibody binds to a specific antigen; an interaction similar to a lock and key. ...

The exact components of raw milk varies by species, but it contains significant amounts of saturated fat, protein and calcium. Aquatic mammals, such as seals and whales, produce milk that is very rich in fats and other solid nutrients when compared with land mammals' milk. Saturated fat is fat that consists of triglycerides containing only saturated fatty acids. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... General Name, Symbol, Number calcium, Ca, 20 Chemical series alkaline earth metals Group, Period, Block 2, 4, s Appearance silvery white Standard atomic weight 40. ... Families Odobenidae Otariidae Phocidae Pinnipeds (fin-feet, lit. ... Whales are the largest species of exclusively aquatic placental mammals, members of the order Cetacea, which also includes dolphins and porpoises. ...

Humans, like other mammals, can consume mother's milk during their infancy. In many ethnic groups, people lose the ability to digest milk after childhood (that is, they become lactose intolerant), so many traditional cuisines around the world do not feature dairy products. On the other hand, those cultures that do tolerate milk have often exercised great creativity in using the milk of domesticated ruminants, especially cows, but also sheep, goats, yaks, water buffalo, horses and camels. For millennia, cow's milk has been processed into dairy products such as cream, butter, yoghurt, ice cream, and especially the more durable and easily transportable product, cheese. Industrial science has brought us casein, whey protein, lactose, condensed milk, powdered milk, and many other food-additive and industrial products. Trinomial name Homo sapiens sapiens Linnaeus, 1758 Humans, or human beings, are bipedal primates belonging to the mammalian species Homo sapiens (Latin: wise man or knowing man) in the family Hominidae (the great apes). ... Introduction A cuisine (from the French word for kitchen) is a specific set of cooking traditions and practices, often associated with a place of origin. ... Dairy products are generally defined as foodstuffs produced from milk. ... Dogs and sheep were among the first animals to be domesticated. ... A ruminant is any hooved animal that digests its food in two steps, first by eating the raw material and regurgitating a semi-digested form known as cud, then eating the cud. ... COW is an acronym for a number of things: Can of worms The COW programming language, an esoteric programming language. ... Species See text. ... Species See Species and subspecies The goat is a mammal in the genus Capra, which consists of nine species: the Ibex, the West Caucasian Tur, the East Caucasian Tur, the Markhor, and the Wild Goat. ... Binomial name Bos grunniens Linnaeus, 1766 Subspecies Bos grunniens grunniens Bos grunniens mutus The yak (Bos grunniens) is a long-haired humped domestic bovine found in Tibet and throughout the Himalayan region of south central Asia, as well as in Mongolia. ... For the controversy at the University of Pennsylvania, see Water buffalo incident. ... Binomial name Equus caballus Linnaeus, 1758 The horse (Equus caballus, sometimes seen as a subspecies of the Wild Horse, Equus ferus caballus) is a large odd-toed ungulate mammal, one of ten modern species of the genus Equus. ... For other uses, see Camel (disambiguation). ... Cream is a dairy product that is composed of the higher-butterfat layer skimmed from the top of milk before homogenization. ... Butter is commonly sold in sticks (pictured) or blocks, and frequently served with the use of a butter knife. ... Yoghurt or yogurt, less commonly yoghourt or yogourt (see spelling below), is a dairy product produced by bacterial fermentation of milk. ... Missing image Ice cream is often served on a stick Boxes of ice cream are often found in stores in a display freezer. ... Cheese is a solid food made from the milk of cows, goats, sheep, and other mammals. ... Casein is the most predominant phosphoprotein found in milk and cheese. ... Whey protein is the name for a collection of globular proteins that can be isolated from whey, a by-product of cheese manufactured from cows milk. ... Lactose is a disaccharide that consists of β-D-galactose and β-D-glucose molecules bonded through a β1-4 glycosidic linkage. ... Can of Black & White condensed milk for international trade Condensed milk is cows milk from which water has been removed and to which sugar has been added, yielding a very thick, sweet product that can last for years without refrigeration. ... Photo of powdered milk Powdered milk is a powder made from dried milk solids. ...

Human milk is fed to infants through breastfeeding, either directly or by expressing the milk to be stored and consumed later. Some cultures, historically or presently, continue to use breast milk to feed their children until as old as seven years.^[1] It has been suggested that the section Benefits for the infant from the article Breastfeeding be merged into this article or section. ... A human infant In basic English usage, an infant is defined as a child at the youngest stage of life, especially before they can walk or simply a child before the age of one. ... Breastfeeding an infant Symbol for breastfeeding (Matt Daigle, Mothering magazine contest winner 2006) Breastfeeding is the feeding of an infant or young child with milk from a womans breasts. ... Breastfeeding an infant Symbol for breastfeeding (Matt Daigle, Mothering magazine contest winner 2006) Breastfeeding is the feeding of an infant or young child with milk from a womans breasts. ...

The term milk is also used for non-animal substitutes such as soy milk, rice milk, almond milk, and coconut milk, and even the regurgitated substance pigeons feed their young, called crop milk, which bears little resemblance to mammalian milk. A can of Yeos soy milk, poured into a glass A convenient pack Soy milk (also called soymilk, soya milk, soybean milk, soy bean milk, soy drink, or soy beverage) is a milk-like beverage made from soybeans. ... Rice milk is a kind of grain milk processed from rice. ... Almond milk is a milky drink made from ground almonds. ... Coconut Milk is a sweet, milky cooking base derived from the meat of a mature coconut. ... Pigeon redirects here. ... This article does not cite its references or sources. ...

History

Holstein cattle, the dominant breed in industrialized dairying today.

Milking has its advent in the very evolution of placental mammals. While the exact time of its appearance is not known, the immediate ancestors of modern mammals were much like monotremes, including the platypus. Such animals today produce a milk-like substance from glands on the surface of their skin, but without the nipple, for their offspring to drink after hatching from their eggs. Likewise, marsupials, the closest cousin to placental mammals, produce a milk-like substance from a teat-like organ in their pouches. The earliest immediate ancestor of placental mammals known seems to be eomaia, a small creature superficially resembling rodents, that is thought to have lived 125 million years ago, during the Cretaceous era. It almost certainly produced what would be considered milk, in the same way as modern placental mammals. Image File history File links Holstein_cows_large. ... Image File history File links Holstein_cows_large. ... Holstein Cow The Holstein or Holstein-Friesian (the latter referring to a smaller, heavier breed) is a cattle breed used in dairy farming. ... Eutheria is a classification system nearly synonymous with Placentalia. ... Families †Kollikodontidae Ornithorhynchidae - Platypus Tachyglossidae - Echidnas †Steropodontidae Monotremes (monos, single + trema, hole; refers to the cloaca) are mammals that lay eggs instead of giving birth to live young like marsupials (Metatheria) and placental mammals (Eutheria). ... Binomial name Ornithorhynchus anatinus (Shaw, 1799) Platypus range (indicated by darker shading)[3] The Platypus (Ornithorhynchus anatinus) is a semi-aquatic mammal endemic to eastern Australia, including Tasmania. ... Orders Didelphimorphia Paucituberculata Microbiotheria Dasyuromorphia Peramelemorphia Notoryctemorphia Diprotodontia Sparassodonta (extinct) Marsupials are mammals in which the female typically has a pouch (called the marsupium, from which the name Marsupial derives) in which it rears its young through early infancy. ... Eomaia scansoria (dawn mother) is a recently discovered extinct mammal that may be one of the earliest ancestors of the eutheria yet to have been found. ... The Cretaceous Period is one of the major divisions of the geologic timescale, reaching from the end of the Jurassic Period (i. ...

Animal milk is first known to have been used as human food at the beginning of animal domestication. Cow's milk was first used as human food in the Middle East. Goats and sheep were domesticated in the Middle East between 9000 and 8000 BC^{[citation needed]}. Goats and sheep are ruminants: mammals adapted to survive on a diet of dry grass, a food source otherwise useless to humans, and one that is easily stockpiled. The animals were probably first kept for meat and hides^{[citation needed]}, but dairying proved to be a more efficient way of turning uncultivated grasslands into sustenance: the food value of an animal killed for meat can be matched by perhaps one year's worth of milk from the same animal, which will keep producing milk — in convenient daily portions — for years (McGee 8–10). COW is an acronym for a number of things: Can of worms The COW programming language, an esoteric programming language. ... A map showing countries commonly considered to be part of the Middle East The Middle East is a region comprising the lands around the southern and eastern parts of the Mediterranean Sea, a territory that extends from the eastern Mediterranean Sea to the Persian Gulf. ... For the animal, see goat. ... Species See text. ... Domesticated animals, plants, and other organisms are those whose collective behavior, life cycle, or physiology has been altered as a result of their breeding and living conditions being under human control for multiple generations. ... A map showing countries commonly considered to be part of the Middle East The Middle East is a region comprising the lands around the southern and eastern parts of the Mediterranean Sea, a territory that extends from the eastern Mediterranean Sea to the Persian Gulf. ... This article does not adequately cite its references or sources. ... Orders Subclass Monotremata Monotremata Subclass Marsupialia Didelphimorphia Paucituberculata Microbiotheria Dasyuromorphia Peramelemorphia Notoryctemorphia Diprotodontia Subclass Placentalia Xenarthra Dermoptera Desmostylia Scandentia Primates Rodentia Lagomorpha Insectivora Chiroptera Pholidota Carnivora Perissodactyla Artiodactyla Cetacea Afrosoricida Macroscelidea Tubulidentata Hyracoidea Proboscidea Sirenia The mammals are the class of vertebrate animals primarily characterized by the presence of mammary... Natural vegetation dominated by grasses Grass is a common word that generally describes a monocotyledonous green plant in the family Poaceae. ... Mortal Kombat character, see Meat (Mortal Kombat). ... Hides are skins obtained from animals that are used for human use. ... An Inner Mongolia Grassland. ... Mortal Kombat character, see Meat (Mortal Kombat). ...

Around 7000 BC, cattle were being herded in parts of Turkey. There is evidence of milk consumption in the British Isles during the Neolithic period. The use of cheese and butter spread in Europe, parts of Asia and parts of Africa. Domestic cows, which previously existed throughout much of Eurasia, were then introduced to the colonies of Europe during the Age of exploration.^{[citation needed]} Binomial name Bos taurus Linnaeus, 1758 Cattle (often called cows in vernacular and contemporary usage, or kye as the Scots plural of cou) are domesticated ungulates, a member of the subfamily Bovinae of the family Bovidae. ... Location of the British Isles The British Isles are a group of islands off the north west coast of continental Europe comprising Great Britain, Ireland and a number of smaller islands. ... The Neolithic, (Greek neos=new, lithos=stone, or New Stone Age) was a period in the development of human technology that is traditionally the last part of the Stone Age. ... Cheese is a solid food made from the milk of cows, goats, sheep, and other mammals. ... Butter is commonly sold in sticks (pictured) or blocks, and frequently served with the use of a butter knife. ... World map showing the location of Europe. ... World map showing the location of Asia. ... A world map showing the continent of Africa Africa is the worlds second-largest and second most-populous continent, after Asia. ... Eurasia African-Eurasian aspect of Earth Eurasia is the Earths largest landmass covering about 21215121321km² compared with the Americas (approximately 42,000,000 km²), Africa (approximately 30,000,000 km²), and Antarctica (approximately 13,000,000 km²). Eurasia comprises the traditional continents of Europe and Asia. ... The so-called Age of Exploration was a period from the early 15th century and continuing into the early 17th century, during which European ships were traveled around the world to search for new trading routes and partners to feed burgeoning capitalism in Europe. ...

Modern production

Main article: Dairy farming

In the Western world today, cow's milk is produced on an industrial scale. It is by far the most commonly consumed form of milk in the western world. Commercial dairy farming using automated milking equipment produces the vast majority of milk in developed countries. Types of cattle such as the Holstein have been specially bred for increased milk production. According to McGee, 90% of the dairy cows in the United States and 85% in Great Britain are Holsteins (McGee 12). Other milk cows in the United States include Ayrshire, Brown Swiss, Guernsey, Jersey, and Milking Shorthorn. The largest producers of dairy products and milk today are India followed by the United States^[2] and New Zealand. Dairy farming is a class of agricultural, or more properly, an animal husbandry enterprise, raising female cattle, goats, or certain other lactating livestock for long-term production of milk, which may be either processed on-site or transported to a dairy for processing and eventual retail sale. ... COW is an acronym for a number of things: Can of worms The COW programming language, an esoteric programming language. ... Dairy farming is a class of agricultural, or more properly, an animal husbandry enterprise, raising female cattle, goats, or certain other lactating livestock for long-term production of milk, which may be either processed on-site or transported to a dairy for processing and eventual retail sale. ... // Automatic milking Automatic milking is the milking of dairy animals without human labour. ... Binomial name Bos taurus Linnaeus, 1758 Cattle (often called cows in vernacular and contemporary usage, or kye as the Scots plural of cou) are domesticated ungulates, a member of the subfamily Bovinae of the family Bovidae. ... Holstein Cow The Holstein or Holstein-Friesian (the latter referring to a smaller, heavier breed) is a cattle breed used in dairy farming. ... Ayrshire Cow The Ayrshire cattle is a breed of dairy cattle originated from Ayrshire in Scotland. ... Brown Swiss is the breed of dairy cattle that produces the second largest quantity of milk per annum. ... The Milking Shorthorn is a breed of dairy cattle that originated in Britain. ...

Other milk animals

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

In addition to cows, the following animals provide milk used by humans for dairy products: Image File history File links Download high-resolution version (1200x900, 78 KB) Goat during milking at goat breeders and goat cheese producers farm in La Roque dAnthéron near Aix-en-Provence, May 2005 Autor/Author/Auteur: --wpopp 16:31, 17 May 2005 (UTC) File links The... Image File history File links Download high-resolution version (1200x900, 78 KB) Goat during milking at goat breeders and goat cheese producers farm in La Roque dAnthéron near Aix-en-Provence, May 2005 Autor/Author/Auteur: --wpopp 16:31, 17 May 2005 (UTC) File links The... Binomial name Bos taurus Linnaeus, 1758 Rainbow arching over a paddock of cattle Cattle are domesticated ungulates, a member of the subfamily Bovinae of the family Bovidae. ...

• Sheep (the ewe)
• Goats (the nanny)
• Horses (the mare)
• Donkeys
• Camels (including the South American camelids)
• Yaks
• Water buffalos
• Reindeers

In Russia and Sweden, small moose dairies also exist. Donkey and horse milk have the lowest fat content, while the milk of seals contains more than 50% fat.^[3] Species See text. ... Species See Species and subspecies The goat is a mammal in the genus Capra, which consists of nine species: the Ibex, the West Caucasian Tur, the East Caucasian Tur, the Markhor, and the Wild Goat. ... Binomial name Equus caballus Linnaeus, 1758 The horse (Equus caballus, sometimes seen as a subspecies of the Wild Horse, Equus ferus caballus) is a large odd-toed ungulate mammal, one of ten modern species of the genus Equus. ... Binomial name Equus asinus Linnaeus, 1758 For other uses, see Donkey (disambiguation). ... For other uses, see Camel (disambiguation). ... Species  Lama glama  Lama guanicoe  Vicugna pacos  Vicugna vicugna  Camelus dromedarius  Camelus bactrianus The four llamas and two camels are camelids: members of the biological family Camelidae, the only family in the suborder Tylopoda. ... Binomial name Bos grunniens Linnaeus, 1766 Subspecies Bos grunniens grunniens Bos grunniens mutus The yak (Bos grunniens) is a long-haired humped domestic bovine found in Tibet and throughout the Himalayan region of south central Asia, as well as in Mongolia. ... For the controversy at the University of Pennsylvania, see Water buffalo incident. ... Binomial name Rangifer tarandus (Linnaeus, 1758) Reindeer map The reindeer, known as caribou when wild in North America, is an Arctic and Subarctic-dwelling deer (Rangifer tarandus). ... Binomial name Alces alces (Linnaeus, 1758) Moose range map The moose (so named in North America, derived from Eastern Abenaki moz)[1] or elk (in Europe), Alces alces, is the largest member of the deer family Cervidae, distinguished from the others by the palmate antlers of its males. ... Families Odobenidae Otariidae Phocidae Pinnipeds (fin-feet, lit. ...

Whale's milk, not used for human consumption, is one of the highest-fat milks. It contains, on average, 10.9% protein, 42.3% fat, and 2.0% lactose, and supplies 443 kcal of energy per 100 grams^{[citation needed]}. A Fin Whale The term whale is ambiguous: it can refer to all cetaceans, to just the larger ones, or only to members of particular families within the order Cetacea. ... A calorie is a unit of measurement for energy. ...

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 or metabolic diseases, etc.).

All other female mammals do produce milk, but are rarely or never used to produce dairy products for human consumption.

Physical and chemical structure

Milk is an emulsion of butterfat globules within a water-based fluid. Each fat globule is surrounded by a membrane consisting of phospholipids and proteins; these emulsifiers keep the individual globules from joining together into noticeable grains of butterfat and also protect the globules from the fat-digesting activity of enzymes found in the fluid portion of the milk. In unhomogenized cow's milk, the fat globules average about four micrometers across. The fat-soluble vitamins A, D, E, and K are found within the milkfat portion of the milk (McGee 18). A. Two immisicible liquids, not emulsified; B. An emulsion of Phase B dispersed in Phase A; C. The unstable emulsion progressively separates; D. The surfactant (purple outline) positions itself on the interfaces between Phase A and Phase B, stabilizing the emulsion An emulsion is a mixture of two immiscible (unblendable... Butterfat or milkfat is the fatty portion of milk. ... An image of Bok globules in the H II region IC 2944, taken with the WFPC2 instrument on the Hubble Space Telescope A Bok globule is a dark cloud of dense dust and gas in which star formation sometimes takes place. ... Two schematic representations of a phospholipid. ... An emulsion is a mixture of two immiscible substances. ... Neuraminidase ribbon diagram An enzyme (in Greek en = in and zyme = blend) is a protein, or protein complex, that catalyzes a chemical reaction and also controls the 3D orientation of the catalyzed substrates. ... A micrometre (American spelling: micrometer, symbol µm) is an SI unit of length equal to one millionth of a metre, or about a tenth of the diameter of a droplet of mist or fog. ... Fat soluble refers to properties of compounds in our bodies that are attracted to and accumulated in fat cells within the body. ... Vitamin A is an essential human nutrient. ... Vitamin D is a fat soluble vitamin that contributes to the maintenance of normal levels of calcium and phosphorus in the bloodstream. ... Tocopherol, or Vitamin E, is a fat-soluble vitamin in eight forms that is an important antioxidant. ... Vitamin K1 (phylloquinone). ...

Schematic of a micelle.

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 percent 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, kappa-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^[4] (McGee 19–20). Image File history File links MicelleSchematic. ... Image File history File links MicelleSchematic. ... Schematic of a micelle. ... Casein is the most predominant phosphoprotein found in milk and cheese. ... Schematic of a micelle. ... Calcium phosphate is the name given to a family of minerals containing calcium ions (Ca2+) together with orthophosphates (PO43-), metaphosphates or pyrophosphates (P2O74-) and occasionally hydrogen or hydroxide ions. ... Electric charge is a fundamental property of some subatomic particles, which determines their electromagnetic interactions. ... In general, a colloid or colloidal dispersion is a substance with components of one or two phases, a type of mixture intermediate between a homogeneous mixture (also called a solution) and a heterogeneous mixture with properties also intermediate between the two. ... This article or section is in need of attention from an expert on the subject. ...

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 — Guernsey and Jersey cows, for instance — 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 can sometimes be discerned in skim milk or whey products (McGee 17). Fat-free skim milk has only the casein micelles to scatter light, and they tend to scatter shorter-wavelength blue light more than they do red, giving skim milk a bluish tint.^[5] Riboflavin (E101), also known as vitamin B2, is an easily absorbed micronutrient with a key role in maintaining health in animals. ...

A simplified representation of a lactose molecule being broken down into glucose and galactose.

Milk contains dozens of other types of proteins besides 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 around twenty percent of the protein in milk, by weight. Lactoglobulin is the most common whey protein by a large margin (McGee 20–21). Image File history File links Lactose_color. ... Image File history File links Lactose_color. ... Lactose is a disaccharide that consists of β-D-galactose and β-D-glucose molecules bonded through a β1-4 glycosidic linkage. ... Glucose (Glc), a monosaccharide (or simple sugar), is the most important carbohydrate in biology. ... Galactose (also called brain sugar) is a type of sugar found in dairy products, in sugar beets and other gums and mucilages. ... Percentages are relative to US recommendations for adults. ...

The carbohydrate lactose gives milk its sweet taste and contributes about 40% of whole cow milk's calories. Lactose is a composite of two simple sugars, glucose and galactose. In nature, lactose is found only in milk and a small number of plants (McGee 17). Other components found in raw cow milk are living white blood cells. Mammary-gland cells, various bacteria, and a large number of active enzymes are some other components in milk(McGee 16). Lactose is a disaccharide found in milk. ... Lactose is a disaccharide that consists of β-D-galactose and β-D-glucose molecules bonded through a β1-4 glycosidic linkage. ... Glucose (Glc), a monosaccharide (or simple sugar), is the most important carbohydrate in biology. ... Galactose (also called brain sugar) is a type of sugar found in dairy products, in sugar beets and other gums and mucilages. ... A scanning electron microscope image of normal circulating human blood. ... Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ... Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ...

Processing

A milking machine in action.

In most Western countries, a centralised dairy facility processes milk and products obtained from milk (dairy products), such as cream, butter, and cheese. In the United States, these dairies are usually local companies, while in the southern hemisphere facilities may be run by very large nationwide or trans-national corporations (such as Fonterra). Image File history File links Download high resolution version (2070x1760, 431 KB) gdgdgdfgsdg A cow milking machine Français Cette photo a été prise le 7 mars 2003 au Salon de lagriculture à Paris, France English This photo was taken on March 7, 2003 at the Salon de lagriculture... Image File history File links Download high resolution version (2070x1760, 431 KB) gdgdgdfgsdg A cow milking machine Français Cette photo a été prise le 7 mars 2003 au Salon de lagriculture à Paris, France English This photo was taken on March 7, 2003 at the Salon de lagriculture... The term Western world or the West (also on rare occasions called the Occident) can have multiple meanings depending on its context (i. ... A dairy farm near Oxford, New York in the United States. ... Cream is a dairy product that is composed of the higher-butterfat layer skimmed from the top of milk before homogenization. ... Butter is commonly sold in sticks (pictured) or blocks, and frequently served with the use of a butter knife. ... Cheese is a solid food made from the milk of cows, goats, sheep, and other mammals. ... southern hemisphere highlighted in yellow (Antarctica not depicted). ... Fonterra Co-operative Group Ltd (generally referred to simply as Fonterra) is a large New Zealand dairy company. ...

Pasteurization and raw milk

Pasteurization kills many harmful microorganisms by heating the milk for a short time and then cooling it for storage and transportation. Pasteurized milk is still perishable 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. In many countries it is illegal to sell milk that is not pasteurized. Pasteurization (or pasteurisation) is the process of heating food for the purpose of killing harmful organisms such as bacteria, viruses, protozoa, molds, and yeasts. ... A microorganism or microbe is an organism that is so small that it is microscopic (invisible to the naked eye). ... Distressed inventory is basically any stock whos potential to be sold at the normal price has passed or will soon pass. ...

Milk may also be further heated to extend its shelf life through ultra-high temperature treatment (UHT), which allows it to be stored unrefrigerated, or even longer lasting sterilization. Ultra-high temperature, or UHT, processing is the partial sterilization of food by heating it for a short time at a temperature significantly above 100°C, typically 135-140°C. The high temperature reduces the processing time, which reduces the danger of spoiling. ... Sterilization (or sterilisation) is the elimination of all transmissible agents (such as bacteria, prions and viruses) from a surface, a piece of equipment, food or biological culture medium. ...

Those preferring raw milk argue that the pasteurization process also kills beneficial microorganisms and important nutritional constituents. The resulting pasteurized product is said to be less digestible, be less nutritious, and turn rancid (as opposed to sour) with age. However, unpasteurized milk can harbor harmful disease-causing bacteria such as tuberculosis, brucellosis, salmonella, diphtheria, and escherichia coli.^[6] The cows must be maintained in very sanitary conditions and a watchful eye kept as to disease testing and vaccinations for this to be completely safe. Cheeses made with raw milk are regarded as safer as the milk typically had to be heated to some extent anyway to make the cheese, and this would kill many of the dangerous organisms possibly present. Raw milk is milk that has not been pasteurized or homogenized before consumption. ... Pasteurization (or pasteurisation) is the process of heating food for the purpose of killing harmful organisms such as bacteria, viruses, protozoa, molds, and yeasts. ... Rancidification is the decomposition of fats and other lipids by hydrolysis and/or oxidation. ... Wikipedia does not have an article with this exact name. ... Tuberculosis (abbreviated as TB for Tubercle Bacillus) is a common and deadly infectious disease that is caused by mycobacteria, primarily Mycobacterium tuberculosis. ... Species Salmonella bongori Salmonella enterica Salmonella arizonae Salmonella enteritidis Salmonella typhi Salmonella typhimurium Salmonella is a genus of rod-shaped Gram-negative enterobacteria that causes typhoid fever, paratyphoid fever, and foodborne illness. ... E. coli redirects here. ...

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 is often sold as a separate product with its own uses; today the separation of the cream from the milk is usually 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 milk much quicker 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 (McGee 19). 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; cream is very slow to separate from these milks (McGee 19). Cream is a dairy product that is composed of the higher-butterfat layer skimmed from the top of milk before homogenization. ... A laboratory tabletop centrifuge A centrifuge is a piece of equipment, generally driven by a motor, that puts an object in rotation around a fixed axis, applying force perpendicular to the axis. ...

Milk from Ireland.

Milk is often homogenized, a treatment which 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.^[7] 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 briefly 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 (McGee 23). Creamline, or cream-top, milk is unhomogenized; it may or may not have been pasteurized. Some have suggested that homogenized milk is harder to digest or not as suited to some people as is unhomogenized, it was just for convenience so one didn't have to shake the bottle, and isn't as important as is pasteurization which is done for safety purposes. Image File history File linksMetadata Download high-resolution version (1944x2592, 1002 KB) My Own photo I, the creator of this work, hereby release it into the public domain. ... Image File history File linksMetadata Download high-resolution version (1944x2592, 1002 KB) My Own photo I, the creator of this work, hereby release it into the public domain. ... Homogenization is a term used both in agricultural science and in cell biology. ... In fluid dynamics, turbulence or turbulent flow is a flow regime characterized by chaotic, stochastic property changes. ... This article or section does not cite any references or sources. ... This article explains the meaning of area as a Physical quantity. ... Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ... Rancidification is the decomposition of fats and other lipids by oxidation. ...

Unhomogenized has made a small comeback in a few areas, such as the west coast of the United States where Straus Family Creameries, based originally out of Sonoma, sells one line of organic milk with the cream still on top in old-fashioned glass bottles. They still however pasteurize it to prevent harmful microorganisms. A Holstein cow at pasture Straus Family Creamery is a successful, innovative, and progressive small family run organic dairy in the western United States. ... Sonoma is a town located in Sonoma County, California, USA. As of the 2000 census, the city had a total population of 9,128. ...

Nutrition and health

The composition of milk differs widely between 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 can vary.Introduction to Dairy Science and Technology, webpage of University of Guelph For example: Butterfat or milkfat is the fatty portion of milk. ... An image of Bok globules in the H II region IC 2944, taken with the WFPC2 instrument on the Hubble Space Telescope A Bok globule is a dark cloud of dense dust and gas in which star formation is taking place. ... Curd is a dairy product obtained by curdling (coagulating) milk with rennet or an edible acidic substance such as lemon juice or vinegar and then draining off the liquid portion (called whey). ...

• 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, and supplies 66 kcal of energy per 100 grams. See also Nutritional benefits further on.

It has been suggested that the section Benefits for the infant from the article Breastfeeding be merged into this article or section. ... BIC pen cap, about 1 gram. ... COW is an acronym for a number of things: Can of worms The COW programming language, an esoteric programming language. ... A glass of cows milk. ...

Nutritional benefits

Milk began containing differing amounts of fat during the 1950s. A serving (1 cup or 250 ml) of 2%-fat 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, 8 grams of protein, and a number of other nutrients (either naturally or through fortification): Lactose is a disaccharide found in milk. ... Lactose is a disaccharide that consists of β-D-galactose and β-D-glucose molecules bonded through a β1-4 glycosidic linkage. ... In chemistry, especially biochemistry, a fatty acid is a carboxylic acid often with a long unbranched aliphatic tail (chain), which is either saturated or unsaturated. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... Vitamin A is an essential human nutrient. ... Thiamine mononitrate Thiamine or thiamin, also known as vitamin B1, is a colorless compound with chemical formula C12H17ClN4OS. It is soluble in water and insoluble in alcohol. ... Riboflavin (E101), also known as vitamin B2, is an easily absorbed micronutrient with a key role in maintaining health in animals. ... Cobalamin or vitamin B12 is a chemical compound that is also known as cyanocobalamine. ... Vitamin D is a fat soluble vitamin that contributes to the maintenance of normal levels of calcium and phosphorus in the bloodstream. ... General Name, Symbol, Number calcium, Ca, 20 Chemical series alkaline earth metals Group, Period, Block 2, 4, s Appearance silvery white Standard atomic weight 40. ... Introduction Magnesium is an essential element in biological systems. ... General Name, Symbol, Number potassium, K, 19 Chemical series alkali metals Group, Period, Block 1, 4, s Appearance silvery white Standard atomic weight 39. ... Reference Daily Intake (RDI) is the daily dietary intake level of a nutrient considered sufficient to meet the requirements of nearly all (97–98%) healthy individuals in each life-stage and gender group. ... General Name, Symbol, Number calcium, Ca, 20 Chemical series alkaline earth metals Group, Period, Block 2, 4, s Appearance silvery white Standard atomic weight 40. ... Recommended Dietary Allowance (RDA) is the daily dietary intake level of a nutrient that is considered sufficient to meet the requirements of nearly all (97-98%) healthy individuals in each life-stage and gender group. ... BIC pen cap, about 1 gram. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ...

• Vitamins D and K are essential for bone health.
• Iodine is a mineral essential for thyroid function.
• Vitamin B12 and riboflavin are necessary for cardiovascular health and energy production, and B12 is difficult to get outside of animal products or else as supplemental pills.
• Biotin and pantothenic acid are B vitamins important for energy production.
• Vitamin A is critical for immune function.
• Potassium and magnesium are for cardiovascular health.
• Selenium is a cancer-preventive trace mineral.
• Thiamine is a B-vitamin important for cognitive function, especially memory
• Conjugated linoleic acid is a beneficial fatty acid that inhibits several types of cancer in mice, it has been shown to kill human skin cancer, colorectal cancer and breast cancer cells in vitro studies, and may help lower cholesterol and prevent atherosclerosis; only available in milk from grass-fed cows.

Studies show possible links between low-fat milk consumption and reduced risk of arterial hypertension, coronary heart disease,colorectal cancer and obesity. Overweight individuals who drink milk may benefit from decreased risk of insulin resistance and type 2 diabetes.^[9] Vitamin D is a fat soluble vitamin that contributes to the maintenance of normal levels of calcium and phosphorus in the bloodstream. ... Vitamin K1 (phylloquinone). ... General Name, Symbol, Number iodine, I, 53 Chemical series halogens Group, Period, Block 17, 5, p Appearance violet-dark gray, lustrous Standard atomic weight 126. ... Cobalamin or vitamin B12 is a chemical compound that is also known as cyanocobalamine. ... Riboflavin (E101), also known as vitamin B2, is an easily absorbed micronutrient with a key role in maintaining health in animals. ... Vitamin H redirects here. ... Pantothenic acid, also called vitamin B5, is a water-soluble vitamin required to sustain life. ... Vitamin A is an essential human nutrient. ... General Name, Symbol, Number potassium, K, 19 Chemical series alkali metals Group, Period, Block 1, 4, s Appearance silvery white Standard atomic weight 39. ... General Name, Symbol, Number magnesium, Mg, 12 Chemical series alkaline earth metals Group, Period, Block 2, 3, s Appearance silvery white solid at room temp Standard atomic weight 24. ... Se redirects here. ... For the similarly-spelled nucleic acid, see Thymine Thiamine or thiamin, also known as vitamin B1, is one of the B vitamins. ... The chemical strucuture of linoleic acid showing physiological numbering (red) and chemical numbering (blue) conventions. ... Arterial hypertension, or high blood pressure is a medical condition where the blood pressure is chronically elevated. ... This article or section does not adequately cite its references or sources. ... Insulin resistance is the condition in which normal amounts of insulin are inadequate to produce a normal insulin response from fat, muscle and liver cells. ... For the disease characterized by excretion of large amounts of very dilute urine, see diabetes insipidus. ...

Interestingly, a study has shown that for women currently desiring to have a child, women who consume full fat dairy products may actually slightly increase their fertility, while women consuming low fat dairy products may slightly reduce their fertility through interference in ovulation, however studies in this area are still inconsistent.^[10]

Nutritional/physiological detriments

The following additional issues are often cited as warranting consideration:

• Milk contains casein, a substance that breaks down, when digested by humans, into several chemicals including casomorphine, an opiate. Milk products are therefore suspected by some to play a role in behavioral disorders among children[2], especially with regards to autism.
• Some even go so far as to promote casein-free diets for everyone[3]. It is also one of the reasons cited by some vegans, for avoiding dairy as well as meat[4].
• Lactose intolerance, discussed below.
• Milk that has not received a fat content reduction is rich in saturated fat and cholesterol, which numerous sources have suggested as contributing to an increased risk of atherosclerosis and coronary heart disease when consumed in excessive quantity. Low-fat and non-fat forms of milk may mitigate this risk^{[citation needed]}.
• Cow milk allergy (CMA) is as an immunologically mediated adverse reaction to one or more cow's milk proteins. Rarely is it severe enough to cause death.
• Milk from contaminated or heavily polluted areas can contain high levels of toxic compounds that have bioaccumulated into it. The nuclear power plant disaster at Chernobyl in Ukraine spread a cloud of radioactivity that ended up in the milk supply and many animals had to simply be killed. The contamination spread across many areas of Europe and affected the dairy industries and even milk as far away as the United States had detectable levels of contamination. As well through the principle of bioaccumulation, herbicides and pesticides can accumulate in milk, and organic milk produced without chemicals has become one of the most popular organic products that people choose.
• There are some fringe groups debating the amount of calcium from milk that is actually absorbed by the human body.^[11] However, calcium from dairy products has greater bio-availability than calcium from vegetable products. ^[12]

• Several studies have shown that men who drink large amount of milk and consume dairy products may increase their risk of developing Parkinson's disease. The reason behind this is, however, not fully understood and it also remains unclear why this is not the case for women. ^{[13] [14]}
• 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.^[15] A large study specifically implicates dairy.^[16] 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,^{[citation needed]} however randomized clinical trial data with appropriate controls only exists for calcium, not dairy produce, where there was no correlation.^[17]

Casein is the most predominant phosphoprotein found in milk and cheese. ... Casomorphin is a peptide sequence that is found in whey protein called casein, and which can be addictive to humans and cause an opiate effect. ... In medicine, the term opiate describes any of the narcotic alkaloids found in opium. ... Autism is classified by the World Health Organization (WHO) and American Psychological Association as a developmental disability that results from a disorder of the human central nervous system. ... Hens kept in cramped conditions — the avoidance of animal suffering is the primary motivation of people who become vegans A vegan is a person who avoids the ingestion or use of animal products. ... A glass of cows milk. ... This article or section does not adequately cite its references or sources. ... In some children the ingestion of cows milk can trigger the body into launching an inappropriate immune response to the proteins in milk resulting in an allergic reaction. ... Chernobyl reactor 4 after the disaster, showing the extensive damage to the main reactor hall (image center) and turbine building (image lower left) The Chernobyl disaster was a major accident at the Chernobyl Nuclear Power Plant on April 26, 1986 at 01:23 a. ... Chernobyl area. ... If the input of a toxic substance to an organism is greater than the rate at which the substance is lost, the organism is said to be bioaccumulating that substance. ... It has been suggested that this article or section be merged with Daily values. ... Prostate cancer is a disease in which cancer develops in the prostate, a gland in the male reproductive system. ... The World Cancer Research Fund (WCRF) is a cancer research umbrella organization based in London, England. ... The American Institute for Cancer Research (AICR) is a large cancer research organisation in the USA. It is [a] cancer charity that fosters research on diet and cancer prevention and educates the public about the results. ...

Controversy surrounding milk and milk production

A number of advocate groups have sprung up protesting that milk presents a health threat. While whole and other fattened forms of milk contain a large amount of saturated fat and cholesterol, factors which are known contributors to the risk of heart disease and many individuals are lactose intolerant, no study has concluded any causal health risk to normal individuals consuming moderate quantities of skim and fat-free varieties of milk. Heart disease is an umbrella term for a number of different sexes diseases which affect the heart and is the leading cause of death in the United States as of 2006. ...

Common claims cited by anti-milk advocates:

• White blood cells -- Milk contains varying levels of white blood cells, depending upon the health of the source animals; controversy surrounds whether these are simply somatic cells or, in an alternate form, pus.^[18] In the United States, one to seven drops of these cells are in every eight-ounce glass of milk, varying by state, according to guidelines set up by the Food and Drug Administration and statistics reported by the dairy industry.^[19] Only one state out