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From: The eUpdate, 4.9.13

Pest Threats: Keeping the Enemy Out

Processing facilities must be more vigilant about preventing pests from adulterating the food supply

by Jim Fredericks, PhD

Managers of food processing facilities know all too well that proper pest management is among the most important and often the most challenging health requirement they must meet. The FDA quite clearly and understandably states that no pests shall be allowed in any area of a food plant and that effective measures shall be taken to exclude pests from the processing areas to protect against the contamination of food on the premises by pests (21CFR110.35). However, that is much easier said than done as these types of food facilities provide perfect conditions for a variety of pests by offering readily available food, water, and shelter for nesting. For example, raw food items and packaging materials may serve as pest harborage sites; the type of lighting used on the exterior and the loading docks of the facility may actually be attracting pests; dust, grease, high temperatures, and excessive moisture often present in food processing facilities can also render pest eliminating products ineffective. These are just a few of the many challenges facility managers face.

To help mitigate these pitfalls, it is crucial that facility managers work in close partnership with qualified pest control companies that have commercial experience. Any pest-proofing measures put in place should also be clearly communicated to employees to ensure they help the facility remain in compliance. Simple steps like identifying key entry points and establishing clear lines of communication among all employees can go a long way in minimizing pest infestations and the associated consequences.

Loading docks are one of the main entry points and most vulnerable areas that attract pests in a food processing facility. Managers can reinforce these areas by installing either metal flashing, inflatable dock cushions, or folding dock covers to prevent pest entry.

If facility managers are going to be successful in their battle against pests, not only do they need to be aware of proper prevention and detection techniques, but most importantly, they must know their enemy. Here are the most common pests found in and around food processing plants:

The Enemy—Rodents: Rodents, including mice, Norway and roof rats, present the biggest problem in food processing and storage facilities. The frequency with which mice and rats urinate and defecate allows for accumulation of excrement, which easily spreads bacteria and contaminates food. These rodent droppings are known to transmit pathogens that cause diseases such as Salmonellosis. In addition to numerous health risks, rodents can chew through wallboard, cardboard, wood, and even electrical wiring, causing expensive damage and posing a fire hazard. Each year, rats contaminate and destroy enough food worldwide to feed 200 million people.

The Control: Eliminate harborage areas by creating open areas whenever possible, inside and outside the facility. Fill in all cracks, fan, and vent openings and install or repair door seals and sweeps as necessary. Ensure the loading dock area is not used for storage and that facility doors are kept closed. Install a gravel or rock perimeter around the facility to discourage vegetation growth to prevent rodent harborage areas. Pest professionals may employ a variety of methods such as traps, glue boards, and baits to control and eliminate rodent infestations.

The Enemy—Flies: The common house fly has been found to carry more than 100 kinds of disease-causing germs, including Salmonella and Listeria. The house fly and other filth flies, breed in moist or decaying garbage or excrement. By moving from garbage and excrement to fresh food, processing equipment, and other surfaces, flies have ample opportunities to transmit disease-causing bacteria and contaminate everything they come into contact with.

The Control: The single best way to control flies is by removing and eliminating their breeding sites—i.e. garbage. Keep garbage areas away from the building and ensure it is removed frequently. Institute a “no-prop” door policy for employees and install air curtains and/or screens to keep flying insects out. Professionals will employ insect light traps placed strategically to provide multiple lines of defense against flies and other flying insects.

The Enemy—Cockroaches: Cockroaches are easily the most reviled pest and with good reason. They are known to spread at least 33 kinds of bacteria, six parasitic worms, and at least seven other types of human pathogens, including Salmonella, Vibrio cholera, and Staphylococcus aureus. They also pick up germs and bacteria on their legs while crawling through sewage and debris, which is then easily transferred to food, food surfaces, and processing equipment.

The Control: Eliminate harborage sites such as stacked cardboard boxes and prevent entry by sealing and filling cracks and crevices and pipe and conduit openings throughout the facility. Also be sure to perform thorough inspections of all incoming shipments for live or dead specimens and their eggs.

The Enemy—Stored Product Pests: This category of pests includes Indian meal moths, numerous beetles, and weevils, which can infest plant equipment and contaminate food by leaving body parts and cast skins inside. Another concern is that these pests may accidentally be ground up into food products or infest flour, grains, and cereals that are then shipped to grocery stores, restaurants, and eventually homes.

The Control: Scheduled cleaning and maintenance of infestation prone areas is key to minimizing the likelihood of infestations. Pest professionals utilize pheromone traps and employ treatments when controlling these pests.

The Bottom Line
The presence of pests—dead or alive—poses significant health risks that can have a devastating economic impact on a facility and company. Production lines can be shut down, inspections failed, fines incurred, and even worse, negative media publicity about a significant infestation could ruin a company’s reputation with consumers. No matter the size or severity of an infestation, a pest problem is never a situation to be taken lightly. Although some facility managers may be tempted to control costs by eliminating or reducing professional pest management programs, the infestations that could occur and the resulting impact on the manufacturer could be far more costly than the preventative program itself.

Skimping on professional pest control isn’t economical, but it could be detrimental. Remain in compliance by understanding the pests that can be a threat and work with a professional pest control firm to develop the best maintenance program for the facility.

Dr. Fredericks is an entomologist and the director of technical services for the National Pest Management Association. The NPMA (, a non-profit organization with more than 7,000 members, was established in 1933 to support the pest management industry's commitment to the protection of public health, food, and property. He can be reached at

For more information on pest management, go to “Integrated Pest Management for Maximum Food Processing Facility Protection,” from our February/March issue.



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