Material Advances Provide a Better Way to Keep Pests out of Food Plants

Chemicals and other remedies may be effective in temporarily resolving a food plant’s pest infestation, but the right materials for keeping critters out in the first place is a wiser approach.

By Kevin T. Higgins, Managing Editor

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By and large, food companies turn to specialists to build and monitor defenses against the insects, rodents and other pests drawn to production plants and distribution centers. And by and large, those pest-management professionals do an effective job of checking traps and assessing the effectiveness of prevention programs.

Responsibility for safeguarding the structural integrity of the property, on the other hand, remains squarely on the shoulders of the food company. Plugging the holes and filling the gaps seems simple enough, but choice of materials and awareness of the opportunities for the entrance of various pets are variables distinct to every facility.

For example, every pipe and conduit that pierces the walls, roof or foundation of the building provides a gap for insects and most rodents. Steel wool or caulk often is used to fill those gaps. Unfortunately, steel wool quickly rusts and fails when exposed to the elements, and the imperceptible contractions and expansions of the structure itself create fissures when conventional caulks are used.

“We don’t even like to use the word ‘caulk’” when advising companies, says Shane McCoy, director-quality & technical training at Wil-Kil Pest Control (, Menomonee Falls, Wis. He recommends specialty products like the concrete-friendly elastomeric polyurethane sealant NP 1 from BASF or the Geocel products from Sherwin-Williams.

Some facility managers upgrade to copper-mesh wool fibers such as Stuf Fit from Pest Control America, McCoy adds, though he believes a better choice is Xcluder stainless steel and poly fiber fill fabric. The material also is incorporated inside neoprene rubber door sweeps to thwart rodents that otherwise would gnaw through the sweep.

Entomologists and technical experts in the pest-control field echo McCoy’s aversion to caulk. The best approach to pest exclusion is dependent on the opening being filled and the materials to which it is applied. For small gaps in walls, a silicone sealant is best, while an epoxy filler is best for creating a durable bond between concrete and metal, suggests Judy Black, vice president-technical services at Charlotte, N.C.-based Rentokil Steritech (

Regardless of the materials used, it’s important that they be approved for food contact or be clad in food-safe materials when used in production areas, she emphasizes.

Rising temperatures are expanding the habitat of roof rats, which are moving north and up the coasts as far as Boston and Washington state. “Look up at the roof line for any vents that have a screen knocked off,” advises Chelle Hartzer, technical services manager at Orkin Commercial Services (www.orkin/, Atlanta.

Whether it’s a missing screen or a worn-out door sweep, pest exclusion materials fail over time. Periodic replacement and proper installation is an ongoing need in effective exclusion programs.

Opting for specialty repair products usually means paying a premium price, of course, and that can drive penny wise, pound foolish repairs. Those materials are purchased from maintenance budgets, and maintenance workers may be tempted to apply a stopgap remedy using materials that won’t hold up.

Doors and windows

Dock levelers on shipping and receiving doors are vulnerable to pest invasions, according to Drew McFadden, director-marketing & research for Xcluder, a brand of Global Material Technologies (, Buffalo Grove, Ill. In recent years, his firm replaced its door bottom seal with X2, a combination weather seal and pest barrier that includes a brush that blocks out light, a feature that auditors and health inspectors like, McFadden says.

X2 slides into an existing retainer, which “dramatically reduces the cost compared to our prior product,” he says. It is complemented with pull-chain seals, side seals and other dock-door barriers.

Screens on overhead doors and windows are a compromise between pest exclusion and the need for fresh air. Black recommends a mesh of 0.038 inches, which should keep out all but the smallest insects. Entomologist Jerry Heath, product manager at IFC (, Lenexa, Kan., points out that insects typically land on a screen rather than fly directly inside. Some insecticides are approved for direct application to a screen, providing a kill step before an insect can enter.

Air curtains sometimes are promoted as an exclusion tool, though positive air pressure “is a better tactic,” assuming a facility’s HVAC system can produce sufficient pressure, adds Heath. If an air curtain’s flow is not properly positioned, it can suck bugs into the building.

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