California Code, Health and Safety Code - HSC § 114057

(a) Potentially hazardous foods that are packed by the food facility in reduced-oxygen packaging or have been partially cooked and sealed in any container or configuration that creates anaerobic conditions shall be plainly date coded. The date coding shall state “Use By,” followed by the appropriate month, day, and year.

(b) For purposes of this section, “partially cooked” means potentially hazardous foods that have not been sufficiently cooked to assure commercial sterility or fail to have barriers to prevent the growth of or toxin formation by Clostridium botulinum.