Cheese is a food made from the milk of cows, goats, sheep and other mammals, by coagulating the milk. There are hundreds of types of cheese produced all over the world. Different styles and flavors of cheese are the result of using milk from various mammals or with different butterfat contents, employing particular species of bacteria and molds, and varying the length of aging and other processing treatments. Other factors include animal diet and the addition of flavoring agents such as herbs, spices, or wood smoke. Whether the milk is pasteurized may also affect the flavor. Cheeses are eaten both on their own and cooked as part of various dishes.