How to Evict Sneaky Rodents from Your Facility

Editor's Note: This article originally appeared in the print edition of QA under the headline "I Spy."

They’re there. In the midst of the shadows lie — rodents.

These pests enjoy living in the cracks and crevices, overhead conduits and unseen shadows of a facility. Occasions could be few and far between that employees sight a rodent’s sprint from one area to another, said entomologist Chelle Hartzer of 360 Pest and Food Safety Consulting.

“Rodents are small, sneaky and scared,” Hartzer said. “They’re going to tend toward the [darker areas] and edges where it’s harder to see them. You can’t wait until you see the rat or mouse, because at that time, they probably have been there for a while.”

Like humans, rodents rely on food, water and shelter for comfort — but how do you eliminate the food from food facilities? Hartzer discussed need-to-know behavior signs and shared her tips for treating rodent break-ins.

MINDSET SHIFT. Let’s go back to the million-dollar question: How do you eliminate food in a rodent’s life cycle? It’s impossible. That’s right, there’s no going around eliminating food altogether in a plant that’s designed to package food.

Keeping that in mind, whether you’re a food facility supervisor or it’s your first day on the job, making sure sanitation is No. 1 on your to-do list will shorten the lifespan of rodents camping out onsite.

“If we can limit the amount of waste so they have a tougher time finding that food, we know that rodents develop and reproduce slower when they’re starving,” Hartzer said. “Doing that mental shift to reduce the amount and access of food versus eliminating food altogether is the key to success.”

It’s a team effort, Hartzer said, adding that every employee must be responsible for enforcing sanitation measures.

“There’s always going to be some waste and spillage, but you should have a regular cleaning schedule,” she said. “Someone should be checking that list and checking it off when they do it.”

With as little access to food as possible, rodents will be robbed of their comfortable living environment.

“When people think about sanitation, they think of trying to remove everything,” Hartzer said. “Switch that thinking to eliminating the amount and access, because we’re never going to get rid of all of it.”

MONITORING RODENTS. In QA’s 2023 State of the Market Report: Rodent Control in Food Facilities survey, conducted by Readex Research, readers were asked to rate how much worry specific pests cause on a scale of one to five, and rodents and flies tied for first, ranking 3.2 out of five. Sixty-seven percent of survey respondents said they have seen a rodent inside or outside of their facility.

While rodent monitoring with bait traps, glueboards and bait stations is an age-old practice, food safety and quality assurance specialists are also using new technologies to monitor rodents differently. In the past few years, digital pest monitoring has been instituted more frequently in facilities to outsmart rodents’ quick, sneaky behavior, Hartzer said.

“Put the digital monitor on that trap, and when something goes in it, it’s immediately alerted,” she said. “Instead of checking traps daily, you will know when something is going on and you can go right to that location, find out how that mouse got in and address those root causes right away, so you don’t continue to have those problems.”

Fifty-three percent of food safety professionals said they are familiar with remote monitoring, and only 17 percent are very familiar, according to the rodent control report.

“What’s nice is all of those other traps that haven’t gone off, you don’t have to check them, so now you can spend more time on the inspection, insect issues and sanitation issues where before you would be checking a whole lot of traps.”

SPYING SECONDARY SIGNS. Rodents tend to hide and maneuver around equipment. Hartzer said that since it’s not so easy to spot rodents themselves, it’s important to be on the lookout for secondary signs like holes in packaging or food spillages.

“Make sure you have good, detailed notes and pictures of the secondary signs, because when you sweep the floors every day, you could be sweeping that evidence away,” she said.

Once secondary signs are spotted, setting up baits and traps will help get you one step closer to treating the problem.

“You could have 100 snap traps set down, but if they are not in the right place, they are useless,” Hartzer said. “Getting those traps in the path that they’re traveling to have the rodent intercepted, that will be beneficial.”

Due to their protective nature, rodents are always looking for dark areas where they can’t be seen. They are also nocturnal, and because they are small prey for most other animals, they see anything bigger than themselves as a threat and try to avoid it.

“They stick to dark, shadowed areas, even at night, and run along floor and wall junctions to keep them in contact with a solid surface,” she said. “They are naturally very cautious and will find any hiding spots they can along the way.”

Due to their protective nature, rodents are always looking for dark areas where they can’t be seen.

LOOK UP. To combat scheming behavior, Hartzer said it’s important to have a 360-degree view when looking for signs of rodents.

“They like running along the upper conduits because there are no people up there, and it’s safe for them,” she said.

Looking up every so often is an important proactive measure, Hartzer said. Even if you see droppings on the floor, they may have come from above.

“We always focus on the ground, but we have to remember that especially with roof rats and house mice, they move vertically as well,” she said. “If your rat problem is up in a drop ceiling or they’re running across conduits overhead, those traps on the floor won’t do you any good.”

Hartzer added that sanitation issues are often missed when they are higher up.

“[An] inspection should cover the roof,” she said. “Roof rats especially will use lines and large trees to cross into food facilities.”

PROACTIVE VS. REACTIVE. Constantly being one step ahead of rodents will run their survival clock down faster.

Hartzer said working an interior integrated pest management (IPM) program requires reactionary measures, like checking traps. But working an exterior IPM program means taking proactive measures like looking at sanitation around employee rest areas, trash cans and overgrown shrubs.

“We might have fruit trees outside, and that’s a nice place for them to hide, or even employee areas that are outside that rodents can take advantage of the trash,” she said. “If you have a bait station that is completely empty when you check it, that means your rodent pressure is pretty high in that area.”

From Hartzer’s experience, some food facilities will prioritize interior treatments over exterior. Having a treatment plan for both the interior and exterior of a facility is needed to stop a rodent in its tracks before making its way into the building.

“I think it’s just as important to look at outside areas as well as inside areas,” she said. “A lot of people are used to keeping the box clean, and that’s been drilled into them, but when you don’t step outside of the box, exterior services could get forgotten about.”

Proactive measures start with sanitation and exclusion efforts. Good inspections will help find sanitation issues and openings that need sealed.

“They’re always looking for dark areas where they feel protected and going through some small holes that you wouldn’t think a rat could squeeze itself through,” Hartzer said.