The milk of various animals has been used in the making of cheese: the milk of mares and goats by the ancient Greeks, camel's milk by the early Egyptians, and reindeer's milk by the Laplanders. Sheep's milk and goat's milk are still widely used, but cow's milk is most common. The milk may be raw or pasteurized, sweet or sour, whole, skimmed, or with cream added.
Cheese, especially in the United States, is increasingly made in the factory by application of the principles of microbiology and chemistry. The chief milk protein, casein, is coagulated by the enzyme action of rennet or pepsin, by lactic acid produced by bacterial action, or by a combination of the two. The draining off of the whey (milk serum) is facilitated by heating, cutting, and pressing the curd. The yield of cheese is usually about 10 lb per 100 lb of milk and is higher for the soft cheeses, which retain more moisture. Wisconsin is the largest producer of cheese in the United States.
The byproduct whey consists of water, lactose, albumin, soluble minerals, fats, and proteins. Formerly wasted or used in livestock feeding, whey is now used for the preparation of milk sugar, lactic acid, glycerin, and alcohol, or is condensed and added to process cheese. It may be made into cheese such as the Scandinavian primost and mysost.
The numerous cheeses (often named for their place of origin) depend for their distinctive qualities on the kind and condition of the milk used, the processes of making, and the method and extent of curing. They may be divided into two classes, hard cheeses, which improve with age under suitable conditions, and soft cheeses, intended for immediate consumption. Very hard cheeses include Parmesan and Romano; among the hard cheeses are Cheddar, Edam, Emmental, Gouda, Gruyère, Provolone, and Swiss. The semisoft cheeses include brick, Gorgonzola, Limburger, Roquefort, Muenster, and Stilton; some of the soft cheeses are Brie, Camembert, cottage, Neufchâtel, and ricotta.
Microorganisms introduced, or permitted to develop, in cheese during the ripening process impart distinctive flavors and textures. Roquefort, Stilton, and Gorgonzola owe their bluish marbling to molds; Emmental and brick are ripened by bacteria that produce gas, which is entrapped in the curd and thus forms holes, a distinctive feature of what in the United States is known as Swiss-style cheese; Limburger attains a creamy consistency through bacteria-ripening. During the curing period the casein is broken down into a more digestible form by enzyme action. Cheese is valuable in the diet as a source of protein, fat, insoluble minerals (calcium, phosphorus, sulfur, and iron), and, when made from whole milk, vitamin A. Process cheese is a blend of young and ripened cheeses or of different varieties, ground, heated with water and up to 3% of emulsifying salts, and poured into molds, usually loaf-shaped. It is often homogenized and pasteurized. Certain cheeses, such as American Baby Swiss, have become popular because of heightened interest in healthful low-fat, low-salt foods. For the same reasons, goat cheeses such as Chèvre, Montrachet, and Bucheron, have grown in appeal to health food adherents and gourmets.
See E. Edelman and S. Grodnick, The Ideal Cheese Book (1986).