Milk may also be acidified by adding food-grade acidulants in the manufacture of certain varieties of cheese, such as cottage cheese. In unripened cheeses such as creamed cottage and cream cheeses, the curd, separated from the whey, can be used immediately. According to federal regulations, all unripened cheese moved in interstate commerce must be made from milk pasteurized at not less than 145 F for at least 30 minutes. In ripened cheeses such as Cheddar and Swiss, the curd is further treated by the action of beneficial select strains of bacteria, molds, yeasts, or combinations of any of these ripening agents, resulting in a cheese of a specific flavor, texture, and appearance.
Cheese can be natural or blended.
Natural cheese such as Cheddar is produced directly from milk. Pasteurized blended cheese, process cheese, cheese foods, cheese spreads, and cold-pack cheeses are made by blending one or more different kinds of natural cheese into a homogenous mass. Optional ingredients may be added. Federal Regulations . Cheese marketed interstate or imported is required to comply with federal standards of identity.