Definition: Casein is a milk protein commonly used in processed foods. You’ll find it in many non-dairy creamers and soy cheeses. As it is derived from milk, casein is not vegan but it is vegetarian. Although many vegans do not mind a small amount of casein in their soy cheese, most avoid these products. Caseinates, such as calcium caseinate, potassium caseinate and sodium caseinate are derived from casein and as such, are also not vegan. If you are allergic to dairy, you should avoid both casein and caseinates.