7 C.F.R. § 54.16

All products examined for class and grade under the official standards, or the immediate containers and the shipping containers, shall be stamped, branded, or otherwise marked with an appropriate official identification. Except as otherwise directed by the Director, such markings will not be required when an applicant desires only an official memorandum. The marking of products, or their containers, as required by this section shall be done by official graders or under their immediate supervision.