Whether contaminants are also concentrated depends on the concentration method that is used. For example, the protein concentrates from whey or milk are obtain

Whether contaminants are also concentrated depends on the concentration method that is used. For example, the protein concentrates from whey or milk are obtained by just two filtrations through filters with different pore sizes, the first coarse filter retains any larger particles, including bacteria, while the second fine filter retains the protein particles and passes the water with lactose and fat and also with any contaminants that are soluble in fat or in water. Thus the protein concentrates from whey or milk normally have less contaminants than in the whey or milk used for their production.