As a result of the isolation of outbreak strains of Listeria monocytogenes in the environment of the packing facility and whole cantaloupes collected from cold storage, and the fact that this is the first documented listeriosis outbreak associated with fresh, whole cantaloupe in the United States, FDA initiated an environmental assessment in conjunction with Colorado state and local officials. The results are now available.
FDA identified the following factors as those that most likely contributed to the introduction, spread, and growth of Listeria monocytogenes in the cantaloupes:
Introduction:
– There could have been low level sporadic Listeria monocytogenes in the field where the cantaloupe were grown, which could have been introduced into the packing facility.
– A truck used to haul culled cantaloupe to a cattle operation was parked adjacent to the packing facility and could have introduced contamination into the facility
Spread:
– the packing facility’s design allowed water to pool on the floor near equipment and employee walkways
– the packing facility floor was constructed in a manner that made it difficult to clean
– the packing equipment was not easily cleaned and sanitized; washing and drying equipment used for cantaloupe packing was previously used for postharvest handling of another raw agricultural commodity
Growth:
– There was no pre-cooling step to remove field heat from the cantaloupes before cold storage. As the cantaloupes cooled there may have been condensation that promoted the growth of Listeria monocytogenes
FDA’s findings regarding this particular outbreak highlight the importance for firms to employ good agricultural and management practices in their packing facilities as well as in growing fields. FDA recommends that firms employ good agricultural and management practices recommended for the growing, harvesting, washing, sorting, packing, storage and transporting of fruits and vegetables sold to consumers in an unprocessed or minimally processed raw form.
More on the FDA website.