Foodservice establishments typically dread the thought of pests, as well they should. Not only can pests give you low scores on inspections, they also can cost you money on contaminated foods that must be thrown away—and drive customers right out the door. It is easy to see why pest management is a part of almost any foodservice establishment maintenance, but is it the right kind of pest management? It is becoming increasingly clear that the most effective, healthiest and, in the long run, cheapest method of controlling pests is integrated pest management (IPM).
IPM is the use of integrated techniques, such as exclusion, sanitation and baiting, to control pests, which are any creatures you don’t want inside your food establishment (rats, mice, cockroaches, flies, etc.), utilizing management tools, such as reports on pest location, pest type, needed repairs and processes that get action when action is needed. It utilizes the least toxic methods that will get the job done. (There is no sense in poisoning ourselves when we’re trying to poison something else, is there?) It is knowing your pest so that you can use its own habits and behaviors against it.
Eliminating Vacancies at the Roach Motel
Foodservice establishments attract pests. Food, water and shelter, the three things any pest needs to survive, are all present. Traditionally, cockroaches, for example, are treated monthly by a “crack and crevice” type of application. This is where the exterminator sprays any suspicious-looking areas with a pesticide to kill the cockroaches. Since cockroaches like to hide in narrow areas that touch their bodies both above and below, special attention is paid to cracks in the wall, gaps between shelving, etc. The two species of cockroaches that normally infest foodservice establishments, the German and the brown-banded, are both colonizers. Once they find a place to their liking, they have no reason to leave until you give them one. Other types of roaches, such as the Oriental and the American, are invaders, choosing to come inside only when conditions outside are unfavorable.
One of the major problems with spraying is that sprays don’t just go into cracks and crevices. They can spread and cover food, food contact surfaces and other areas. In addition, this type of treatment kills only cockroaches near the surface, not those that have hidden down deep. Flushing agents within the spray can cause the cockroaches to spread to previously uninfected areas. Additionally, spraying does not penetrate egg cases to kill eggs. When those eggs hatch, the baby cockroaches eat anything they can, grow, reproduce and the cycle begins all over again. You might say that just spraying is like farming cockroaches. You spray (harvesting) the cockroaches, emptying out the environment, which leaves plenty of room and food to let all the cockroaches you didn’t kill thrive. And the cycle starts up again.
Let’s say you wanted to begin an IPM program. You might start by consulting with your pest management professional (PMP, formerly “the exterminator”) and doing a thorough cleaning. This helps remove food sources for the cockroaches, dead cockroaches and egg cases (also a food, and an allergen, source) as well as roach feces and body parts (“frass,” which looks a little like pepper sprinkled around cracks and crevices and is also a food source, particularly for baby cockroaches, as well as an allergen). Cracks and crevices would then be sealed up, eliminating shelter for the cockroaches. Your PMP might want to monitor for current or further infestations by placing sticky traps or bait out in likely areas of infestation.
Bait works very well in cockroach infestations because baits don’t disperse by themselves like sprays do. The cockroaches actually do part of your job for you by eating the bait and then carrying it back to where the other cockroaches have gathered. When they defecate, the feces are poisonous, and the baby cockroaches will eat them and die.
One major concern with baits is that they can be contaminated by sprays, so it is very important not to use any sprays around them. Keep all unauthorized pesticides out of your establishments. One important exception is the type of sprays known as insect growth regulators, which arrest the insect’s development at a stage before it can reproduce. These sprays don’t interfere with the baits’ attractiveness to the cockroach.
There are other steps in controlling roaches that should be discussed with your PMP. What works with cockroaches does not necessarily work with other pests, and vice versa.
Reducing Rodent Overruns
Another type of pest that commonly infests foodservice establishments is rodents. Rats and mice require different strategies for control. Incidentally, just to clear up any confusion, mice are not baby rats. They are two completely different species. All rodents share the common characteristic of a pair of upper and lower incisors, which grow throughout their lives and must gnaw against each other to keep from growing to unmanageable lengths. The name rodent comes from the Latin word “rodere,” which means “to gnaw.” Since rodents are forced to gnaw, they can be very destructive to your property and can cause electrical fires by gnawing on wiring.
The most common rodent pests to man are called commensal, which is Latin for “sharing the same table.” And share it they do; it is estimated that rats and mice consume or contaminate up to one-third of all the food produced in the world annually. In addition to eating food, they constantly urinate and defecate, and spread whatever they’ve been walking through. Mouse dander has also been shown to trigger asthma attacks in sensitive individuals. In addition, both rats and mice are known disease carriers, directly transmitting such diseases as hantavirus, tularemia, plague and salmonellosis, as well as indirectly spreading rickettsialpox and typhus.
Mice. Mice are much smaller than rats, with bodies three to four inches long and tails two to four inches in length. Since they are so small, keeping them out is that much harder. The average mouse can fit in an opening the size of a dime. Mice, like rats, can collapse their rib cages to squeeze through any opening that is bigger than their skulls. Generally, mice wander only about 10 feet from their nesting area, but that 10 feet can be sideways, back and forth and up and down. They build nests in walls or any cluttered area that will hide them. Unlike rats and cockroaches, mice can obtain their water from the food they eat. Mouse droppings are about the size of a grain of rice. Usually, droppings are one of the first signs of an infestation to be noticed. Some other common signs are gnawed food and a musky smell, similar to hamster cages in a pet store.
Mice are curious. When baiting for mice, the strategy that works best is placing either bait or traps where droppings are seen. Leave them in place for a day or two, then move them to a different location. At this time, you can clean up the droppings, which attract mice to the area. Wet down the droppings before you clean them, as the dust from dry droppings is a disease hazard. Then monitor the area for additional activity. If more droppings are spotted, replace the bait after a week to 10 days. Mice are curious, but that curiosity wears off after a day or two, so the baits and/or traps become ineffective. They also have limited memories, so after they forget about the bait and/or traps that have been placed out, they’ll come back for another visit.
Rats. Rats, on the other hand, have been described as neophobic, or afraid of new things. They are much larger than mice, with a body length of up to 10 inches and a tail equally long. Rats weigh, on average, 12 to 19 ounces, with two-pound rats being possible, but rare. Rats the size of cats are exaggerations, possibly the result of seeing one out of the corner of one’s eye, or a different animal entirely, such as a muskrat. Rat droppings are about the size of a jelly bean. Rats are found on every continent except for Antarctica and are, after man and mice, the third most successful mammal on the planet. Rats have been shown to be very intelligent, roughly equivalent to a dog.
Since a rat’s teeth are harder than iron, and they can bite with a pressure of 3½ tons per square inch, it is difficult to keep them out of areas they want to enter. Galvanized steel and glass containers will prevent them from getting into foodstuffs, and holes, cracks and crevices can be blocked using steel mesh. However, it is also true that rats can come up through toilets and broken sewer pipes, in addition to any opening larger than a quarter. Unlike mice, rats do require a source of water, so eliminating any free-standing water in a facility will do a great deal to resolve a rat problem.
Since rats are nervous about new things in their environment, it is often the best strategy to pre-bait using nonpoisonous grains at first, then gradually introducing lethal, slow-acting poisons. Poisons must be both painless and slow acting, because rats will observe their companions to see whether they have adverse reactions. Rats are so intelligent that in large colonies, the smallest and weakest rats are used as tasters. They are the ones that eat the new food, and the rest of the colony watches to see what happens.
Rats are also hierarchical. One successful strategy for baiting or trapping is to search out the best hiding place for rats and bait exclusively at that location. The top rat in the hierarchy will be eliminated; the others that replace him will die in turn until all the rats are gone.
Since both rats and mice are prey animals, they tend to avoid open spaces where they can be seen. A good way to prevent an infestation before it can start is to create an open space around your building. Both rats and mice will be reluctant to cross any space where they could be spotted by one of their predators. Keeping mouse- and/or rat-infested areas clear of clutter will also do a great deal in restricting their ability to hide.
Preventing Insect Invasions
Flies are another major pest problem. They are frequently dismissed as normal, everyday nuisances, but they are, in fact, major disease carriers. They are capable of carrying over 100 pathogens, such as those causing typhoid, cholera, salmonellosis, bacillary dysentery, anthrax and parasitic worms. They are so closely associated with disease that the presence of one fly in an operating room is cause for closing down a surgery. Flies eat only liquid or semiliquid food. Solid food is liquefied by the fly’s saliva or vomit. Since their food intake is so high, they also defecate constantly. Virtually any time a fly lands on a surface, it is either vomiting or defecating, which is why we treat them as a serious issue.
Most foodservice operators become concerned about flies when they see them flying around as adults. However, it is much easier to control them as larvae. Flies hatch from eggs as maggots, feed on wet organic matter and then leave that matter to pupate, emerging from the pupae as adult flies. Wet, organic matter occurs in many places in a foodservice establishment, such as garbage cans, floors and in floor drains. It takes only a day or so for the fly to hatch from the egg, and about a week or more to pupate. Twice-weekly thorough cleaning of wet organic matter from the areas mentioned can completely disrupt the fly’s life cycle. Interior light traps can be used to trap and kill adult flies, but sanitation will reduce fly populations to much more manageable levels.
Outsmarting the Vermin
If there is a common thread for all of these pest control strategies, it is that we have used the creatures’ own habits and lifestyles against them. Cockroaches carry bait back to where they gather and poison their young. Mice are curious and check out baits/traps, then check them out again when they are replaced after a delay. Rats will take baits after they become used to them. Flies are best controlled when they move around the least, that is, when they’re larvae. It is knowing the creature that allows us to eliminate, or at least control, the creature.
Each situation is different, which is why we call this pest management. IPM involves knowledge, effort and time, but it has been shown to be extremely effective and can make your establishment healthier for you, your employees and your patrons.
Article by Michael Swoyer
Michael Swoyer,, is the supervisor of rat control Kansas City, MO, Health Department.