Rodent Control and Food Safety: Proactive Programs are the Key

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Are conventional programs keeping up with the changes in food safety risks and expectations?

August 16, 2013
Bobby Corrigan

Editor’s note: This article is a partial discussion from the Rodent Control and Food Safety Seminar delivered for the June AIB/RK Chemical Seminar on food safety in Hershey, Pa.

Many of the rodent control programs in place at typical food-handling establishments (processing plants, warehousing and distribution centers, and retail stores) are set up with some type of exterior bait/trap stations and interior mouse traps installed according to a pest company’s commercial business plan or according to a facility’s particular third-party audit format. The goal for these designs is to help protect the establishment against rodents that attempt to enter (or are eventually successful at entering) the facility from exterior areas, or even from within a delivery. Both the food-handling establishment (FHE) client and the pest professional traditionally rely on such equipment installments and setups as the primary defense in their protective program against rodents for the facility.

But in today’s climate of globally enhanced food safety programs, are “typical” rodent control programs adequate? Another way of stating this might be to ask: Are conventional programs keeping up with the changes in food safety risks and expectations? Consider, for instance, the relatively recent legislation such as the Food Safety Modernization Act, in which the FDA has raised the bar for meeting the criteria of good manufacturing practices (GMPs).

Adding to this, consider the emergence of the various food safety regulations and auditing programs on a global scale. They truly do read as an alphabet soup. To be a pest professional serving the food industry, it is common to have to consider and understand a list of acronyms way beyond the basics of FSMA, GMPs and HAACP. Acronyms and names such as FQPA, GFI, AIB, SQF, FS 22000, BRC and Global Gap are just a partial listing of where things stand these days in food safety and in pest management as part of all the food safety requirements. (Each of these food safety-related programs [and others] can be researched via Google or other Internet tools.)

So, should the installation of rodent control equipment be the primary defense against rodents in the food industry? And if not, what is primary, secondary and so forth? The fact of the matter is the order should be based on the inherent aspect of the science of rodents and their biology relative to the specifics of food-handling establishments everywhere. This includes, for example, the nature of how rodents invade food facilities from the exterior, their ability to escape detection once inside, and the ability of some rodents to evade even the best-laid trap and exterior baiting schemes.

The purpose of this article is to emphasize the importance proactive rodent pest management programs. And this begins by first thoroughly characterizing a facility relative to its current “rodent profile.” To do this, the primary defense in rodent control and food safety is to confirm, prior to the installation of any equipment, whether or not any rodents or rodent colonies actually are infesting the grounds and/or the facility itself. And if so: a) to what level; and b) the specific locations of any infestations.

Based on such an assessment, the goal then is to determine what will be the specific plan, in addition to the installation of any rodent control equipment to maintain a FHE as “rodent free” as possible. (“Rodent free” on a practical level means as close to zero as possible within the realization of everyday operations, surrounding exterior areas, etc.)

Proactive Programs.
So what does a proactive rodent control program look like? There is no one-size-fits-all type of program. However, I suggest the following eight steps can at least keep a program from slipping into a routine of merely “running the trap line” and relying on the results as the true barometer reading of rodents being present or about at the FHE.

Step 1. Formal rodent assessment of the facility and grounds
Remember, all areas of FSE buildings and grounds are vulnerable to rodent invasions. They do not restrict themselves to traveling along wall perimeters and property line fence rows and the like. Formal detailed rodent assessments for the presence/absence of rodents and a listing of the rodent active areas and the rodent vulnerable areas must be done in proactive programs (see later discussion for some of the areas that must be considered). Based on the assessment and the level of any rodent infestations inside or outside (see Table 1), the next steps as listed can be implemented.

Figure 1. Rodents are arguably the top and most important pests in and around most food-handling establishments. Despite even the best pest management programs, rats and mice are often capable of continually breaching our protective barriers and on-going inspections. Food safety programs must be unrelenting to offset the wily rodent’s constant threat.

Step 2. Professional pricing and bidding for proactive programs
All too often, FHE clients and pest professionals attempt to establish a service cost for the pest management of a FHE before any type of assessment is done. The biggest mistake made in this regard, and what truly can jeopardize food safety, is to submit service bids based solely on the size of the plant (e.g., how many traps will be needed for 60,000 square feet of wall space; the number of exterior bait stations to be installed and the time required to service, etc.).

Proactive rodent control programs that maximize food safety require well-trained and experienced pest professionals. To implement proactive programs, it takes time. And excuse the no-brainer phrase here, but in the service industry, “time means money.” Both parties have an important responsibility within the food safety partnership of pest management: quality pricing from the pest professional, and careful selection from a food company’s procurement specialists. If indeed food safety is paramount to a food company, then selecting a pest professional based solely on a low price is to disregard the overall goal. It’s a safe axiom that for pest threats around food facilities, food safety risks generally increase if the service quality and time (and thus charges) decrease.

Step 3. The installation and servicing of rodent control equipment
In proactive rodent programs, the installation of traps and bait station equipment is essential. But rodent control equipment always should be considered supplemental to the thorough rodent profiling of the facility and ongoing monitoring (surveillance) of areas in the specific facility that are considered “rodent vulnerable.”

Many examples exist of rodent control equipment templates for the food industry and a full description is not the goal of this article (see Corrigan 2001, 2003). Suffice to say, rodent control equipment should be installed in both numbers and in locations based on Step 1, and not on some spatial yardstick measurement. The exception to this and where “yardstick installations” might actually be warranted is when — and for whatever reasons — the FSE is at a Level 4 or worse (see table), and the high rodent pressure demands as much equipment as possible.

If a proactive program is designed according to the initial assessment as described for Step 1, the pest professional will know which parts of the facility are most vulnerable; they will know the best locations for the bait stations and mouse traps. Certainly, rodent activity around large buildings is constantly changing. Equipment needs to periodically be added or relocated depending on the changing environments of the rodents themselves or changes in operations with a facility (e.g., large construction projects).

Figure 2. Interior mouse traps along a food distribution wall. Such traps are an important component of proactive rodent control programs. But they are not more important than proactive inspections for rodent activity away from wall areas.

Step 4. A response plan for new or recurring activity
Rodents can arrive via any number of ways to even the best food facilities. They can scurry from a weedy patch across the parking lot to the first door or hole in the wall that allows them access to the interior. Or they can arrive within a trailer delivery. The point is a food plant or warehouse is always vulnerable to a new rodent incident.

Sometimes, activity — new or old — is noted within the installed traps or bait stations. Other times, activity is noted from employee sightings of rodents or rodent evidence on pallets, along floors, purlins, rafters, wall sill plates and the like. Sometimes, sightings and signs of rodents occur far away from any perimeter wall equipment.

This means that skillful inspections and interpretations of any captures, the monitoring data and/or presence of ARS, is mandatory. Knowing “what to do next” when, say a mouse, has been captured in mouse trap #73, or when exterior bait station #24 is suddenly showing heavy activity, is part of a proactive program. Simply noting that a mouse was captured in MCT #73, and then moving along to the next trap is not proactive.

Rather a professional-level inspection for mouse sebum trails (i.e., grease stains) on the nearest door jamb or hole around a penetrating pipe at the squeeze point, checking a ceiling void above the capture area, or noting the nearest improperly fitting door, should all be part of a response plan as part of a proactive rodent control effort. Note that this is where the time element of providing a professional food safety service is so critical.

Step 5. Proactive inspections for non-wall areas
It is not uncommon for severe rodent infestations to develop and irrupt far away from any perimeter wall trap and/or exterior bait stations. When this happens, these rodents are never captured in any perimeter equipment. Some examples of non-wall area inspections include, but are not limited to:

  • Beneath the slabs in warehouses around the bases of support piers that penetrate through the slabs (between expansion joints where cement slabs meet or surrounds piers).
  • In pallets of incoming goods; these pallets may be slotted for virtually anyplace within a large warehouse.
  • In the damaged goods section (morgue).
  • In aisles containing foods highly attractive to rodents (birdseed, grass seed, bags of dry pet food, etc.).
  • In ceilings voids (especially above heat-generating processing equipment).
  • In insulated walls near high ceiling areas; along roof-level purlins (especially roof rats).
  • In interior dividing walls (especially concrete hollow block and/or insulated sheet rock walls).
  • In office areas; around employees desks/ within cubicle divider walls and bases.
  • Cafeterias and break rooms.
  • Within vending machines.
  • Uncleaned dock leveler voids.
  • Exterior Dumpster areas.

Step 6. Incoming supplies monitoring
The monitoring of incoming supplies is one of the heaviest lifts in rodent pest management for the client. Of course, it is not realistic to expect a food warehouse to inspect each and every pallet and every truck trailer floor for rodent droppings. Nevertheless, unloaders and other warehouse staff must be aware of the need to be alert for rodent stowaways. Mice, in particular, can and do periodically arrive directly into the facility within the everyday thousands of boxes that come off of trailers and are placed into slots.

When rodent droppings or other signs are spotted within any aisle of a plant or a warehouse, this information must be relayed to the pest professional. But just as important, the brands of products in the area of activity should be carefully checked and flagged for future attention. It’s possible (but not absolute) that rodents came in as stowaways with some of those products; and more rodents might come in with future deliveries from those same brand name products.


Figure 3. Food safety demands a partnership between pest professionals and food clients. This exterior bait station, no matter how well placed and well baited, will not prevent rodents from freely entering into the distribution center through this decrepit screen door. Should that happen, the pest professional is often held “to task” for getting rid of the interior infestation of mice that has developed.

Step 7. Open and ongoing communication and review
Communication between the pest professional and the QA team of a FHE must be given top priority. The PMP should be scheduled to meet with the designated food safety team involved with pest prevention and control at the conclusion of any pest management service. It should never be a case of the plant’s shipping/receiving supervisor, or an office employee signing off on the service ticket with an “I’m OK, you’re OK” routine.

If the routine pest service report constantly states “No problems” or “Everything is good,” the fact of the matter is everything is not good with such a pest service. Typically a proactive service from a quality PMP results in several recommendations for the FHE client. These recommendations are best delivered in some type of face-to-face meeting, however brief it may need to be.

Step 8. Quarterly review and progress reports
A review of where the plant is relative to the levels as listed in Table 1 (or whatever other company-tailored profile the partners agree to employ) is important for tracking success and/or chronic rodent infestations requiring additional attention. With rodents, it is not enough to wait until an annual independent third-party audit to take a hard and close look at where things stand relative to progress or threats. Whichever type of assessment is employed, it is important for both parties to have a progress report.

To those outside of pest management, the incredible complexity of rodents and their interactions with us, our large food-handling establishments, and the food distribution chain, is usually not readily visible. Sometimes, clients will reduce rodent control in commercial facilities to: “How many rodents did you capture this month,” or, “How many of the exterior stations are showing activity?” But, of course, this superficial understanding severely under-addresses food safety.

Similarly, the pest professional that services a food-handling establishment must go beyond “running” a trap and bait station line — even if they are using the most advanced bar coding and record keeping technology available. Those involved in food safety in the partnership of pest professionals and food-handling establishments must be trained to see the complexity and details of proactive rodent pest management that most others overlook. Modern day levels of advanced food safety regulations and audits require nothing less.

The author is president of RMC Pest Management Consulting, Richmond, Ind. Email him at


Corrigan, R.M. 2001. Rodent Control: A Practical Guide for Pest Management Professionals. GIE Media. Cleveland, Ohio. 355 pp.

Corrigan, R.M. 2003. Rodent Pest Management for Food Plants. Pages 265-291 in: Food Plant Sanitation. Y.H. Hui, et. al (Eds). Marcel Dekker, New York. 745 pp.