Milk most often means the nutrient fluid produced by the mammary glands of female mammals. The female ability to produce milk is one of the defining characteristics of mammals and provides the primary source of nutrition for newborns before they are able to digest more diverse foods.
It is also processed into dairy products such as cream, butter, yogurt, ice cream, gelato, cheese, casein, whey protein, lactose, condensed milk, powdered milk, and many other food-additive and industrial products. Cow milk is an ingredient for food products such as chocolate and cereal bars. Cow milk in different forms are used as ingredients for certain types of food and beverages. Milk is an important dietary source of fat, protein and calcium.
Human milk is fed to infants through breastfeeding, either directly or by the female expressing her milk to be saved and fed later. 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 both mother and baby.
Milk produced for commercial consumption usually undergoes several processes. 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. Additionally, commercial milk is often homogenized. This mechanically reduces the size of the fat globules, so that they will not separate out into a cream layer. Creamline milk is unhomogenized; it may or may not have been pasteurized.
South Australia has the highest consumption of flavoured milk per person, where Farmers Union Iced Coffee outsells Coca-Cola, a success shared only by Inca Kola in Peru and Irn-Bru in Scotland.
Those preferring raw milk argue that the pasteurization process also kills beneficial microorganisms and important nutritional constituents. The resulting pasteurized product is said to contribute to its own indigestability, be less nutritious, and turn rancid (as opposed to sour) with age. Raw Milk Versus Pasteurized Milk
In the Western world, cow's milk is extracted on an industrial scale for human consumption and industrial uses. It is the most commonly consumed form of milk. Dairy farming has become such a large business that in many countries the process is highly automated, with farmers using machines that attach directly to the teats of the cow's udder to speed milking, and breeds of cattle, such as Holstein, specially bred for increased milk production.
Animal milk was first used as beverage at the beginning of animal domestication. Goats and sheep were domesticated in the Middle East in 9000 BC. Goats and sheep were one of the first animals to be domesticated. Around the year 7000 BC, cattle were being herded in parts of Africa and Turkey. Milk was also consumed in the British Isles during the Neolithic period. Dairy products were first made in the Roman Empire around 100 BC. The use of cheese and butter spread in Europe, parts of Asia and parts of Africa. Cattle were then introduced to European colonies after the Age of exploration.
Animal Milk and Vegetarianism
It has been argued whether consuming milk from animals is vegetarian or not. Animal milk is an animal product and some skeptics believe that its non-vegetarian. Other people believe that milk is vegetarian for there's no meat in milk and no animal was killed to obtain milk. Vegans do not consume any milk or milk based product.
Because of the perishable nature of milk, expeditious distribution is desirable. In many countries milk used to be delivered to households daily, but economic pressure has made milk delivery much less popular, and in many areas daily delivery is no longer available. People buy it chilled at grocery or convenience stores or similar retail outlets. Prior to the widespread use of plastics, milk was often distributed to consumers in glass bottles, and before that in bulk that was ladled into the customer's container. In the UK, milk can be delivered daily by a milkman who travels his local milk round (route) using a battery-powered milk float, although this is becoming less popular as a result of supermarkets selling milk at lower prices. In New Zealand, milk is no longer distributed in glass bottles.
In the United States bottles were replaced with milk cartons, tall boxes with a square cross-section and a peaked top that can folded outward upon opening to form a spout. Now milk is increasingly sold in plastic bottles. First the gallon and half-gallon sizes were sold in plastic jugs while the smaller sizes were sold in milk cartons. Recently milk has been sold in smaller resealable bottles made to fit in automobile cup holders.
The half-pint milk carton is the traditional unit as a component of school lunches. In the US, pictures of missing children were printed on the larger milk cartons as a public service until it was determined that this was disturbing to children. Milk preserved by the UHT process is sold in boxes often called a "brick" that lack the peak of the traditional milk carton. Milk preserved in this fashion does not need to be refrigerated before opening and has a longer shelf life than milk in ordinary packaging. Glass milk containers are rare these days. Most people purchase milk in plastic jugs or bags or in waxed-paper cartons. Ultraviolet light from fluorescent lighting can destroy some of the proteins in milk so many companies that once distributed milk in transparent or highly translucent containers are now using thicker materials that block the harmful rays. Many people feel that such "UV protected" milk tastes better.
Varieties and brands
Cow's milk is generally available in several varieties. In some countries these are:
·Full cream (or "whole" in North America, about 3.25% fat)
·Semi-skimmed ("reduced fat" or "low fat", about 1.5-1.8% fat)
·Skimmed (about 0.1% fat)
In Britain, it is possible to get Channel Island milk, which is 5.5% fat.
Full cream, or whole milk, has the full milk fat content (about 3-4% if Friesian- or Holstein-breed are the source). For skimmed or semi-skimmed milk, all of the fat content is removed and then some (in the case of semi-skimmed milk) is returned. The best-selling variety of milk is semi-skimmed; in some countries full-cream (whole) milk is generally seen as less healthy and skimmed milk is often thought to lack taste. Whole milk is recommended to provide sufficient fat for developing toddlers who have graduated from breast milk or infant formula.
Other milk animals
In addition to cows, the following animals provide milk for dairy products: sheep, goats, horses, donkeys, camels, yaks, etc.
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.
Whale's milk — not generally 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. 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 infants, infants with allergies, metabolic diseases, etc.).
When raw milk is left standing for a while, it turns sour. This is the result of fermentation: lactic acid bacteria turning the milk sugar into lactic acid. This fermentation process is exploited in the production of various dairy products such as cheese and yogurt. Pasteurized cow's milk, on the other hand, spoils in a way that makes it unsuitable for consumption, causing it to assume an unpleasant odor and pose a high danger of food poisoning if ingested. The naturally-occurring lactic acid bacteria in raw milk, under suitable conditions, quickly produce large amounts of lactic acid. The ensuing acidity in turn prevents other germs from growing, or slows their growth significantly. Through pasteurization, however, these lactic acid bacteria are mostly destroyed, which means that other germs can grow unfettered and thus cause decomposition.
In order to prevent spoilage, milk can be kept refrigerated and stored between 1 and 4 degrees Celsius. 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. Sterilized milk, which is heated for a much longer period of time, will last even longer, but also lose more nutrients and assume a still different taste. Condensed milk, made by removing most of the water, can be stored for many months, unrefrigerated. The most durable form of milk is milk powder which is produced from milk by removing almost all water.