The Code of Federal Regulations (21 CFR 133) defines standards of identity for four pasteurized process cheeses:

• Pasteurized process cheese: A blend of fresh and aged natural cheese that have been mixed and heated (cooked) with an addition of an emulsifier salt, after which no further ripening occurs.
• Pasteurized process cheese food: A variation of pasteurized process cheese that contains less fat and has a higher moisture content. It differs from process cheese in that both nonfat dry milk or whey solids and water have been added, thus reducing the percentage of actual cheese in the finished product.
• Pasteurized Process Cheese Spread: Another variation that contains a higher moisture content and lower milkfat content than process cheese food. A stabilizer is added to prevent separation of ingredients.
• Pasteurized Process Cheese Product: A process cheese spread that doesn’t meet the FDA-established moisture and/or minimum fat content.