The specifications for the U .S. grades of butter are as follows:

Butter of all U.S. grades shall be free of foreign materials and visible mold. Butter possessing a flavor rating of AA or A and workmanship disratings in excess of one and one-half (1-1/2) shall be given a flavor rating only; butter possessing a flavor rating of B or C and workmanship disrating in excess of one (1) shall be given a flavor rating only. Butter which fails to meet the requirements for U.S. Grade C or U.S. 89 Score shall not be given a U.S. grade. Butter, when tested, which does not comply with the provisions of the Federal Food, Drug and Cosmetic Act, including minimum milkfat requirements of 80.0 percent, shall not be assigned a U .S. grade. Butter produced in a plant found on inspection to be using unsatisfactory manufacturing practices, equipment, or facilities, or to be operating under in sanitary plant conditions, shall not be assigned a U .S. grade.