In most of the western countries the word "milk" means cow's milk unless otherwise specified, for example "goat's milk". Cows milk is a very nourishing food, yielding 65 Cal. per 100 grams and 1 litre contains, on average, 870 grams water, 39 grams emulsified fats (which gives milk its white colour), 33 grams proteins, 45 grams lactose (milk sugar that some people find difficult to digest and is the cause of some allergies), 7 to 10 grams minerals (mainly calcium) and a variety of Vitamins. Milk's composition has a influence in the type of cheese that is made from it. The flavour of butter is also effected by the diet of the animal that produces the milk.

Milk is a very versatile food. It is the basic ingredient in cream, butter, cheese and yogurt. It can also be a drink that is flavoured or unflavoured on its own or used in conjunction with other things to make other kinds of drinks and recipes. Milk is an indispensable ingredient in modern cookery and is essential for many sauces, such as béchamel, Nantua and soubbise. It may also be used in soups, used in gratin dishes, court-bouillons for certain fish and even in meat cookery (pork roast with milk).

Milk has a multipling amount of microbes which is needed for the coagulation, but it can be farmful. This is why various methods are used to pasteurize or sterilize the milk, thus avoiding deterioration and prolonging the length of time it can be stored in a refrigerator. Unpasteurized milk retains all of its natural flavour. The pasteurized milk goes threw a slight heat treatment , which kills the bacteria and loses a very small amount of the vitamin content.