(a) Each carcass which has been inspected and passed in an official establishment shall be marked at the time of inspection with the official inspection legend containing the number of the official establishment.

　　(b) Except as provided otherwise in § 316.8, each primal part of a carcass and each liver, beef tongue, and beef heart which has been inspected and passed shall be marked with the official inspection legend containing the number of the official establishment before it leaves the establishment in which it is first inspected and passed, and each such inspected and passed product shall be marked with the official inspection legend containing the number of the official establishment where it was last prepared. Additional official marks of inspection may be applied to products as desired to meet local conditions. Primal parts are the wholesale cuts of carcasses as customarily distributed to retailers. The round, flank, loin, rib, plate, brisket, chuck, and shank are primal parts of beef carcasses. Veal, mutton, and goat primal parts are the leg; flank, loin, rack, breast, and shoulder. The ham, belly, loin, shoulder, and jowl are pork primal parts. Equine primal parts are the round, flank, loin, rib, plate, brisket, chuck, and shank.

　　(c) Beef livers shall be marked with the official inspection legend containing the number of the official establishment, at which the cattle involved were slaughtered, on the convex surface of the thickest portion of the organ.

　　(d) Inspected and passed parts of carcasses which are not marked with the official inspection legend under this section shall not enter any official establishment or be sold, transported, or offered for sale or transportation, in commerce, except as provided in § 316.8.