21 CFR §1.1320

1. (a)You must assign a traceability lot code when you do any of the following: Initially pack a raw agricultural commodity other than a food obtained from a fishing vessel; perform the first land-based receiving of a food obtained from a fishing vessel; or transform a food.
2. (b)Except as otherwise specified in this subpart, you must not establish a new traceability lot code when you conduct other activities (e.g., shipping) for a food on the Food Traceability List.