Pest Management in Food Processing Warehouses

Commercial pest management can be synonymous with brand protection, ensuring that a customer never associates pests with a particular food processor or restaurant. As commercial pest management professionals (PMPs), our jobs often are to protect the food supply. This is a serious undertaking that involves protecting food through all stages of its processing, including in the retail environment, in restaurants, and often in a consumer’s home. That consumable item is the last step of a complicated, multi-faceted processing system that takes all different types of ingredients and turns them into something crave-worthy through the magic of food science. It’s that final product that is worthy of protecting.

The production lines on which these products are created are at the forefront of sanitation and pest management protection efforts; however, many of the real risks to that product do not stem from those production lines, but from unlikely, low-profile areas of the facility that have the potential for pest infestations. The building design, process flow, structural and sanitation resources, storage practices, and even neighboring facilities can all directly impact whether the production line feels pest pressure. Additionally, warehousing and receiving areas where ingredients and final products are stored tend to be near production lines, which harbor their own set of pest risks.

Stored Product Pests

Dry ingredients, such as baking mixes, cocoa, nuts, and flour, may enter a food processing facility infested with stored product pests such as Indianmeal moths (Plodia interpunctella), cigarette beetles (Lasioderma serricorne), warehouse beetles (Trogoderma variabile), and flour beetles (Tribolium spp.). Stored product pests live in the food they eat; the food is their home. If the facilities processing and packaging these ingredients have a stored product pest infestation, the product that they are shipping out may have that same infestation, which can in turn infest the destination facility.

Stored product pest population development is a function of time and temperature. The longer a population sits in a container in warm temperatures, the more generations will develop. For this reason, first-in first-out stock rotation is essential. Forgotten totes or pallets of ingredients may hold generations of stored product pests that are quietly devouring the product and growing their population, eventually to a point where they need to find new harborage to infest and spread throughout the warehouse. Using storage containers that prevent these pests from entering or exiting the food can be an excellent tool to minimize risk. Well-sealed plastic or metal storage containers can prevent pests from escaping an infested container and protect product that is not infested. Racking can also be a common source of stored product pest infestations within a warehouse. Product and ingredient spills collect in the beams of the racking and in the racking legs and guards, providing an excellent harborage.

Though we tend to think of stored product pests as internal infestations, several stored product pests, such as the warehouse beetle, have populations on the exterior of a building. These populations are often monitored on the interior through pheromone traps and/or insect light traps (ILTs), but the source may be outside of the building. In such cases, a facility may need to focus on exclusion, using fans, light management, and sealing to keep those outdoor pests on the exterior.

Monitoring and control: Finding infested product in a warehouse can be daunting. With rows of pallets packed high with susceptible ingredients, it may seem as though stored product pests can loom anywhere. To assist with finding stored product pests, PMPs can implement a pheromone program. Pheromones and/or kairomones are placed in tent or pit-fall traps, depending on which species are being targeted. Not all stored product pests have had pheromones synthesized for them, so it is important to remember that we cannot monitor for all stored product pests. Fortunately, the most damaging stored product pests do have synthesized pheromones. The monitoring traps will guide our inspection, telling us what areas of the warehouse have the most activity and warrant our attention. There is no replacement for a detailed and systematic inspection, but with monitoring data, we can find that infestation faster.