Dairy products are a type of food produced from or containing dairy ingredients. A dairy product is said to be "proper" if it can be obtained by separating milk-producing animal tissue at some point in production (not during processing). The Food and Agriculture Organization (FAO) has produced a definition of dairy that requires:

For example, whey products are made from the protein-rich liquid remaining after milk is curdled and strained; cream products may be regarded as dairy products, but they are typically derived from the fatty portion of milk rather than the liquid (milk fat), and butter and cheese products are derived from milk, but neither contains significant Casein or Whey proteins. A number of traditional dairy products can be produced using non-animal-based sources of protein. Some commercial dairy alternative products contain casein, which is extracted from milk.