9 CFR 590.426: Retention.

Retention tags or other devices and methods as may be approved by the Administrator shall be used for the identification and control of products which are not in compliance with the regulations or are held for further examination, and any equipment, utensils, rooms or compartments which are found to be unclean or otherwise in violation of the regulations. No product, equipment, utensil, room, or compartment shall be released for use until it has been made acceptable. Such identification shall not be removed by anyone other than an inspector.