Closing the Door on Rodents: Exclusion Tips and Tricks

By the time a rodent is caught inside a food manufacturing facility, the first line of defense has already failed. That’s why food safety leaders say the industry’s most effective rodent control programs begin with exclusion.

For Andrew Kuszynski, director of continuous improvement and regulatory/SQF practitioner at Schiff Food Products Co. in Totowa, N.J., successful rodent control isn’t determined by how many rodents are caught. It’s measured by how few ever make it in.

“One observation I’ve made over the years is that the best rodent control program is often the least exciting one: keeping rodents from getting inside in the first place,” he said.

This philosophy puts exclusion at the center of Schiff’s Integrated Pest Management (IPM) program.

Rather than reacting to rodent activity, the company focuses on pest-proofing the facility through structural maintenance, door seals, dock controls, utility penetrations and routine inspections. Exterior baiting and monitoring systems are paired with strong sanitation, controlled waste handling and careful management of refuse areas to eliminate food sources and harborage.

Kuszynski said the facility’s location also works in its favor. Schiff, a spice processor, sits next to a commercial bakery.

“If you’re a mouse looking for a midnight snack, fresh bread and sweet baked goods tend to win over cayenne pepper and mustard powder every time,” he quipped.

Even so, the company doesn’t rely on its surroundings.

“Success comes from aggressively managing entry points,” Kuszynski said.

Keep a Look Out.

For Robert Long, exclusion extends well beyond sealing obvious entry points. It includes maintaining the entire facility — from receiving docks and ingredient storage to maintenance shops, locker rooms, wastewater areas and employee breakrooms — in a condition that doesn’t invite pests inside.

“Maintain the facility in a clean and sanitary condition,” said Long, director of corporate food safety and sanitation at Flowers Bakeries, Thomasville, Ga. “That includes all of the areas around the plant, not just where food is produced.”

Survey respondents reported that rodents are most often observed outdoors, particularly around trash and waste areas, warehouses and loading docks. Those findings reinforce the importance of viewing the property perimeter as part of the pest management program rather than simply the area surrounding it.

Jeff Nelken, a Los Angeles-based food safety and HACCP expert, said one of the biggest challenges facilities face today is deferred maintenance. Aging infrastructure often creates exactly the vulnerabilities rodents exploit. Worn door sweeps, deteriorating seals, damaged dock doors and unsealed utility penetrations become easy access points as facilities balance competing priorities.

“Building maintenance is often overlooked, especially during times when facilities are operating under tighter budgets,” Nelken said. “Some will try to ‘Mickey Mouse it’ instead of making sure everything is maintained on schedule.”

Small Gaps, Big Consequences.

Chelle Hartzer, B.C.E., owner of 360 Pest and Food Safety Consulting, said facilities often underestimate just how small an opening rodents need.

“The common thing people say is something the size of a quarter will let a full-grown rat in; something the size of a dime will let a full-grown mouse in,” she said. “It’s probably even smaller than that.”

Doors remain one of the most common problem areas.

“I was just in a facility,” Hartzer said. “It gets hot, people want to open the doors to get some airflow through. But if there’s no screen on that door, they are literally just having them walk into the building.”

She encourages facilities to look beyond obvious entry points. Incoming ingredients, pallets, packaging, refurbished equipment and even long-forgotten machinery can create unexpected risks.

“I call them graveyards,” Hartzer said. “When something sits there for a year or three years without being checked, it provides habitat.”

And culprits change, so exclusion requires continuous evaluation as facilities age, equipment is added and operations evolve.

Exclusion is never a one-and-done effort, agreed Robert Powitz, a forensic sanitarian and founder of R.W. Powitz & Associates in Old Saybrook, Conn. It requires constant observation.

One of his favorite tools for staying on top of rodent activity — and pests in general — isn’t high-tech. It’s a handheld UV flashlight.

“We use it to find biofilm, but it also picks up droppings,” he said. “Mice dribble all over the place.”

Under ultraviolet light, rodent activity becomes much easier to follow. Rub marks, urine stains and well-worn travel routes suddenly become visible, revealing where rodents are moving and, often, where they’re getting inside.

“The runs will show me where rodents get in,” Powitz said. “Now I can plug it up.”