What is the difference between class 1 class 2 and class 3 milk?

milk is classified by usage under federal milk marketing order. all classes are grade A or B milk. that said, class 1 milk is primarily the milk used to produce fluid milk. class 2 milk is the one that produces ice-cream, cottage cheese, yogurt. class 3 milk is the milk used to produce conventional cheese (cheddar cheese for example). class 4 milk is the milk for whatever else, including non-fat dry milk.