Pest Control 101: Getting Pests Under Control

Departments - Practical Pest Protection

December 12, 2019

JORGE PARADA, Medical Advisor for the National Pest Management Association (NPMA)

According to CDC, there are 48 million cases of foodborne illness annually in the U.S. — that’s roughly one in six Americans affected every year. An estimated 128,000 of those are hospitalized, and 3,000 die. Because food can become contaminated at any point during production, packaging, and shipping, food processors have an enormous responsibility as the public’s first line of defense against foodborne illnesses spread by vector pests. To better understand how these illnesses are spread, we’ll explore the most common vector-borne types of food poisoning and the pests notorious for carrying them.

Scientists have identified more than 2,000 strains of Salmonella bacteria, but the two most commonly associated with food poisoning are S. typhimurium and S. enteritidis. CDC estimates there are approximately 1.2 million cases of Salmonella a year in the U.S., with food being the source of about one million — 83% — of the illnesses. Salmonella is a classic cause of water- and foodborne gastroenteritis. While most people recover without treatment, some may require hospitalization because of diarrhea that leads to severe dehydration or life-threatening bacteremia and Salmonella sepsis, including typhoid fever.

There are various strains ofE. coli, and each vary in their presentation. One strain is the infamous traveler’s diarrhea (or “Montezuma’s Revenge”) which typically presents as an acute, watery diarrhea. Though uncommon, some strains produce toxins and can cause bloody diarrhea and complications such as sudden onset anemia and acute renal failure. The incubation period for pathogenic E. coli is one to 10 days, making it difficult to identify the source.

Recognized as a cause of febrile gastroenteritis, symptoms of Listeria are usually self-limited. In pregnant women, however, the infection can lead to miscarriage, stillbirth, premature delivery, or life-threatening infections for the newborn child from neonatal sepsis. It also can cause post-partum bacteremia, threatening the mother’s life. Those who aren’t pregnant may experience headaches, stiff neck, confusion, loss of balance, convulsions, fever, and muscle aches. In rare cases, Listeria can cause meningitis. Symptoms generally present one to four weeks after eating contaminated food.

PEST VECTORS. While many pests serve as vectors of foodborne illness, the most common carriers that plague food plants are rodents, cockroaches, flies, and ants.


Rodents present the greatest problem in food processing facilities and tend to return to the same food source time after time, following the same pathway between their nest and food. They produce 40 to 100 droppings per day, and their fecal matter can contaminate goods and harbor bacteria such as Salmonella.



Cockroaches are common in larger facilities, and usually infest food storage and food preparation areas, boiler rooms, steam tunnels and basements. They have been reported to spread at least 33 kinds of bacteria, including E. coli and Salmonella, as well as six kinds of parasitic worms and at least seven other kinds of human pathogens. They pick up germs on the spines of their legs and body as they crawl through decaying matter or sewage, and then transfer the germs onto food or cooking surfaces.



Common house flies can quickly reproduce in large numbers, leading to large populations within a facility if they are not identified and controlled immediately. In addition to defecating constantly, flies can transfer more than 100 pathogens, including Salmonella and Listeria, to humans. They contaminate food surfaces by spreading diseases picked up on their legs and mouths when feeding on trash, feces, and other decaying substances.



Multiple ant species have been implicated in the spread of more than a dozen disease pathogens, including Salmonella. They are attracted to areas of moisture, including bathrooms and food processing areas, and are known to eat almost any kind of food, most notably sweets and greasy items. Ants can contaminate food through their bodily waste or by transferring diseases picked up on their bodies after crawling on feces and decaying matter.


By understanding the threats associated with vector pests, as well as their habits and preferred habitats, facility managers can better protect their food processing plants from biologic threats. To prevent infestations before they have a chance to materialize, managers should partner with a licensed pest control professional to help implement a holistic integrated pest management (IPM) approach. Comprised of inspection, identification, and treatment, this approach leverages the partnership, allowing treatments to be tailored to each facility’s needs. This proactive pest prevention protects both the facility and the public from the diseases and dangers associated with vector pests.