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The Story of Cheese
Cheese is one of the oldest and most nutritious food
products. It is formed by the coagulation of milk by rennet (the
digestive enzyme in the stomach of the calf) or similar enzymes,
and the draining off of the liquid whey. Part of the moisture
is removed from the curd by cutting, warming, or pressing; then
it is usually shaped in a mold and ripened by storing for some
time at a particular temperature and humidity. The ripening,
or curing, process is the result of bacteriological processes.
In temperate climates, milk from cows is commonly used, and in
mountainous regions from sheep and goats; in hot countries, the
milk of the buffalo; and in cold climates, reindeer, horses,
yaks, and other mammals may be used as a source of milk.
It is believed that the first cheese was produced inadvertently, probably through the practice of carrying milk in pouches made from animal stomachs. The bacteria in the milk and the digestive juices from the stomach worked together to form a curd and then a crude cheese. Cheesemaking artifacts dating from 2000 BC have been found. The Romans developed a large cheese industry, and later, cheesemaking became a specialty of monasteries. Many European abbeys developed secret recipes, and particular varieties began to be developed in certain regions of Europe. Today, although mechanization has largely replaced the old hand-techniques, the characteristics of hundreds of individual cheese types have been preserved. VARIETIES OF CHEESE The following are primarily responsible for the character of a cheese: moisture content, which is controlled by the extent of cutting and draining of the curd; the types of microorganisms added and encouraged to grow; the temperatures and acidities employed in the production process; and the temperature, humidity, and length of maturation, or ripening, time. The percentage of fat in the milk is also important: the higher the fat content, the more mellow and attractive the cheese. Low-fat cheeses are tough and lack flavor. It is impossible to state the number of named varieties of cheese because new names--usually associated with a town or a region--are constantly being introduced. However, cheeses can be classified into major categories, according to several distinguishing characteristics: type of milk used--cow's milk, sheep's milk (Roquefort), or goat's milk (Chevre); degree of hardness--very hard (Parmesan); hard without eyes (Cheddar) or with eyes (Gruyere); semisoft (Muenster); ripened by interior mold (Gorgonzola); ripened by exterior mold (Camembert). Soft cheeses distinct from all others are the unripened cottage cheese and ricotta types, where the drained, pressed curd is eaten fresh, without undergoing the maturing process. Further differentiations include cheeses that are ripened by surface bacteria (Limburger); cheeses that are made by plasticizing the curd in hot water (Caciocavallo); cheeses salted by adding salt to the curd (Cheshire) or immersing the cheese in brine (St. Paulin). Herbs, seeds, alcoholic beverages, and vegetable dyes may also be incorporated. MODERN CHEESEMAKING Until about 1850 most cheese was produced in small dairies. The first cheesemaking factories were merely enlarged forms of the farmhouse dairy, but gradually the equipment became larger and more mechanized. Since 1945 cheesemaking equipment and methods have changed radically. Today factories can handle up to 1,000,000 liters (about 264,000 U.S. gal) of milk a day. Equipment is covered rather than open, and aseptic techniques are used to produce starter. Further improvements include ever-increasing automation, controlled temperatures for maturing, intensive pressing, cutting into retail-size film-wrapped portions after one or two days and allowing the packaged cheese to ripen in storage. All types of cheese are made in the same basic manner, but production details may differ considerably. Because Cheddar is an important cheese type in the United States, Britain, Australia, Canada, and New Zealand and the Cheddar production process employs nearly all the basic treatments used in modern cheesemaking, it is described here in detail. In the factory milk is pasteurized, or heat-treated, at about 70 degrees C (158 degrees F) to kill all common pathogenic bacteria. After cooling to about 30 degrees C (86 degrees F), it is pumped into the cheese vat, a closed cylindrical vessel. Here it is mixed with the starter, which is a culture of lactic streptococci and other organisms. These sour the milk by fermenting the lactose, or milk sugar, to lactic acid, in order to create the acid conditions necessary for the rennet to act. Rennet is a brown liquid prepared by extracting the macerated fourth stomach of the calf with salt solution. It is rich in the digestive enzymes that clot milk. Because of a shortage of calf rennet, coagulating enzymes derived from fungi are now coming into use. Rennet is so powerful that it is mixed with milk in a 1:5,000 ratio. About 30 minutes after it is added to the souring milk, the milk clots and can be cut into tiny cubes by rotating knives that are made of wires set in a harp-shaped frame. After a short time the temperature is raised slowly, by admitting steam to the outer jacket of the cheese vat, until a temperature of about 40 degrees C (104 degrees F) is reached. At this point the curd is solid enough to be matted into a cohesive mass, which is then formed into slabs, salted, drained, and pressed to remove some of the whey. The slabs are placed in cloth-lined metal containers, called hoops, and pressed to form blocks weighing about 18 kg (40 lb). The blocks are either dipped in wax or wrapped in plastic film and left to cure at temperatures of about 10 degrees C (50 degrees F). Although it is considered mature at 3 months, a well-matured Cheddar should be kept for 12 months or longer. A good Cheddar should be homogeneous (without holes or cracks), creamy white or yellow in color, and have a mild cheesy odor. Cheddar is sometimes colored red orange by adding annatto, a vegetable dye, to the milk. NUTRITIONAL VALUE Cheese is a nutritional double-edged sword. On one hand, it is high in protein (particularly hard cheeses such as Cheddar) and is a good source of vitamins and minerals such as calcium, phosphorus, and vitamin A. On the other hand, cheese is high in calories, saturated fat (and thus cholesterol), and sodium. Cheesemakers have responded to concerns about fat and cholesterol by developing reduced-fat cheeses and using skim or part-skim milk to make the cheeses. Because cheese is a high-protein food, in moderation it can be a good nutritional replacement for meat in a vegetarian diet. Used moderately, it is also a particularly good food for children, who do not have the same concerns as adults about cholesterol and calories. Nutritionally, milk is best preserved by condensing or drying, as no part of it is lost. Conversion to cheese is an excellent method, because virtually all the fat and most of the protein are retained, and the latter is partially digested. However, nearly all the sugar (lactose) and some of the minerals, protein, and vitamins escape into the whey. Today cheese whey is condensed or dried and used for animal feeds or special dietary human foods. PROCESSED CHEESE AND CHEESE SPREADS Processed cheese is a mixture of ground cheese (usually Cheddar and other hard varieties), emulsifying salts such as phosphates, other ingredients such as milk powder, whey powder, and coloring and flavoring materials, and sometimes, spices. Vegetable gum is often added to produce a chewy texture. Steam is blown into the mixture to raise the temperature to 80 degrees C (150 degrees F) or higher, which yields a molten plastic mass that is then poured into a metal or ceramic container or into portion-containers for foil wrapping. WORLD PRODUCTION The United States is the largest producer of hard cheese, followed by France, Italy, Germany, and the Netherlands. Mexico, Argentina, Denmark, Russia, and Canada are also high on the list. The largest consumers of cheese include France, Italy, Denmark, the Netherlands, Sweden, Belgium, and the United States. J. G. Davis Bibliography: Fox, P. F., ed., Cheese, 2 vols. (1987); Jenkins, Steven, Cheese Primer (1993); Jones, Evan, The U.S. Cheese Market (1993) and The World of Cheese (1976); Timperley, C., and Norman, C., A Gourmet's Guide to Cheese (1990); U.S. Department of Agriculture, Cheeses of the World (1972).
Images and text from: 1998 Grolier Multimedia Encyclopedia http://gi.grolier.com |
