Cheese in the categorization of these cheeses is their age. Fresh cheeses without additional preservatives can spoil in a matter of days. Content (double cream, goat, ewe and water buffalo) Some cheeses are categorized by the source of the milk used to produce them or by the added fat content of the milk from which they are produced. While most of the world's commercially available cheese is made from cows' milk, many parts of the world also produce cheese from goats and sheep. Some cheeses are described by their fat content. Double cream cheeses are soft cheeses of cows' milk enriched
American cheese American cheese was often simply called "yellow cheese". Today’s American cheese is, by law, required to be manufactured from at least two types of cheese. Because its manufacturing process differs from "unprocessed" traditional cheeses, American cheese cannot be legally sold under the name (authentic) "cheese" in the US. Instead, federal laws mandate that it be labeled as "processed cheese" if simply made from combining more than one cheese, or "cheese food" if dairy ingredients such as cream, milk, skim milk, buttermilk, cheese whey, or albumin from cheese whey are added. As a result, sometimes even the "word" "cheese" is absent