Abstract: Clamshells for packaging produce, or other unit packaging, are labeled with unique codes. Harvest crates for transporting filled clamshells from the harvest, or other containers for transporting unit packaging, are also labeled with unique codes. A plurality of labeled un-filled clamshells are nested together and placed into each harvest crate before the harvest, and the codes from the clamshells and the harvest crate are stored in association. In some instances, clamshells are de-nested, labeled with pre-printed labels, and nested again before being placed into the harvest crates. At the harvest the clamshells are removed from the harvest crate, de-nested, filled with produce, packed back into the harvest crate, and moved into the distribution chain. The unique codes are further associated with other information such as harvest data.

Abstract: Methods are provided for marking products with unique identification codes, associating times with at least some of the unique identification codes, and associating other times with certain events pertaining to the production of the marked products. These times can be used to subsequently determine whether a marked product belongs to a population that was produced before or after an event.