Pest Management in Food Processing Warehouses

Large flies in a warehouse are typically there due to open doors and docks, much like commensal rodents. Light management can play an important part in this too, as these pests are drawn to the light on both the interior and exterior of the facility. Dumpsters and spills are typically the source of these flies, though any moist organic material can provide an acceptable exterior harborage.

Small flies typically come from the interior of the facility. In a warehouse, that may be related to structural or sanitation issues associated with sewers, drains, or cleaning rooms. However, they may also be associated with liquid ingredients that are stored in the warehouse. A thorough inspection based on the food preferences of the species identified will identify the source and dictate the proper control method.

Facilities that process liquid ingredients with spill potential may have more frequent and long-term infestations, particularly if that material seeps onto the floor or into grates.

Monitoring and control: ILTs are often considered a universal flying pest monitoring tool. While they are very effective for some species, others do not respond as strongly to the light. Nonetheless, an ILT is a good first line of defense and monitoring tool to determine what species are in the facility.

Flies are generally not cryptobiotic, meaning they do not try to hide the way rodents and cockroaches do. This can make inspection easier, as adult flies are often very visible. The challenge is finding them in the juvenile stages, which may be hundreds of feet away from where we are seeing the adults. Once the PMP is able to find the source, insecticide may need to be applied (if appropriate) where the juvenile flies are harboring. Insecticides geared towards the adults will provide relief but will not eliminate the problem.

Renowned urban rodentologist Bobby Corrigan, PhD, a consultant with RMC Pest Management, has said that there must be lines of defense in rodent work. That same philosophy holds true when protecting food processing products. If PMPs can keep the areas surrounding food production pest free, then they are more likely to keep dedicated food production areas pest free. Likewise, if the exterior of a facility can be kept pest free, it is more likely that the interior of the building will remain pest free.

It is important to look at the facility as a whole when developing pest programs, paying attention to all the areas that may not be as highly sensitive, but may be high risk. Doing so will keep high sensitivity areas safe, ensuring that the overall food supply is protected.

Berry is a training manager and board-certified entomologist at McCloud Services. Reach her at [email protected].