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


Cow's 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.

History

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.

Distribution

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.