Inspection and grading services assure the quality of dairy products and are offered to the dairy industry on a voluntary basis. Official approval of a manufacturing plant is a prerequisite for grading. Therefore, a consumer can tell if the products were produced in a USDA-approved plant by looking for the grade shield on products such as butter, Cheddar cheese, and instant nonfat dry milk. The shield means that every lot has been certified by an inspector as meeting the grade requirements. It does not necessarily apply to all manufactured products, but only to the specific product on which it appears.

Only after an inspection shows that a plant has substantially met the requirements outlined in USDA's General Specifications for Approved Dairy Plants can the plant qualify for the other services of grading, sampling, testing, and certification of its product.