Milk and cheese contain protein. Cheese is a major dairy product and contains most of the proteins in milk. There are several types of proteins in milk, and the major ones are unique to milk and dairy products.
Milk and dairy products contain two groups of proteins called caseins and whey proteins. The caseins are the primary group, with three to four caseins in the milk of many species. The major whey proteins are alpha-lactoglobulin and beta-lactalbumin. The caseins and the major whey proteins are synthesized only in the mammary glands, while minor whey proteins can be absorbed from the bloodstream.