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Preventing the spread of food-borne illness

Tips to help you protect your produce from physical pest contaminants and indirectly prevent pathogen contamination and food-borne illness.

May 17, 2019  By Alice Sinia Ph.D. Orkin Canada

Photo courtesy of Orkin Canada.

Food-borne illness can create big problems for both public health and a business. Most recently, an outbreak of E. coli made headlines across Canada and the U.S., with 29 confirmed cases in Canada. Romaine lettuce and other leafy greens were recalled by producers and food manufacturers after the outbreak was traced back to farms in California.

The E. coli bacteria that contaminated the greens is commonly transmitted to fruits and vegetables through the feces of infected animals. However, E. coli and other pathogens that cause illness can also be transmitted by infected pests, especially those known to frequent filthy areas, like cockroaches and flies.

Cockroaches will eat just about anything, from feces and garbage to the produce harvested at your facility. If they come into contact with pathogenic bacteria, those germs can reproduce and stay in their stomachs for as long as they are alive. During that time, cockroaches can transmit the bacteria to new surfaces via their saliva, feces and body. In all, cockroaches have been known to spread at least 33 types of bacteria, six kinds of parasitic worms and other pathogens. Allergens from cockroach bodies can also cause gastrointestinal illness in children, the elderly and people with compromised immune systems.


While often considered just a nuisance, flies also breed in and consume garbage and feces – along with sewage and decaying matter – where they can pick up a wide range of pathogens. Flies have filthy feeding habits and when they feed, they regurgitate pathogen-loaded gut content. As a consequence, they transmit pathogens onto any surface or medium they touch or feed on. Because flies land often, they also have plenty of chances to these spread disease-causing pathogens around your facility. Fly populations can grow at an alarming rate, increasing the risk for contamination. Female houseflies, for example, can produce up to 1,000 eggs in her short lifetime of about 21 days. Controlling and eliminating fly populations can be very challenging unless the breeding source and resting sites are found and eliminated.

Rats and mice can directly and indirectly transmit 35 different diseases through their fur, saliva, urine and feces. As they manoeuvre around your facility, a mouse will produce about 49 droppings in a day, and a rat will produce more than 60. Rodents also urinate very frequently, which implies that every surface they come into contact with will have urine stains – and hence, pathogens.

To prevent pests from spreading food-borne illnesses in your fields and storage or processing buildings, it is important to develop an Integrated Pest Management (IPM) plan that focuses on prevention through proper housekeeping practices, structural maintenance, sanitation, exclusion and monitoring. All pests need food, water and shelter to survive, so if you can eliminate and block their access to those elements on your facility and farm, you are one step closer to protecting your produce from food pest-related
food-borne illness. Here are a few tips on how to protect your property:

In the field:

  • Monitor for pest activity regularly. Employ regular field scouting and install trap monitors to detect any infestations early.
  • Remove idle, unused farm and processing equipment as pests may use it for harbourage.
  • Remove rotting or overripe fruits and vegetables. Do not leave them in the field to decay.
  • Do not allow for open garbage decomposition – this is the primary fly breeding medium.
  • Eliminate overgrown weeds, bushes and shrubs next to the field edge.
  • Avoid over-mulching.
  • Inspect all produce at the time of harvest.
  • Clean and sanitize harvest equipment regularly.
  • Avoid bruising produce – the bruising can attract fruit flies.
  • Remove standing water when possible.

In processing and storage:

  • Repair cracks and gaps in walls to prevent pest entry. Rats can fit through holes as small as a quarter, and cockroaches can fit through cracks as thin as a sixth of a cm.
  • Install roll-up doors to keep flies from entering storage and processing areas.
  • Use the first in, first out rule for managing produce. This will ensure less product goes to waste and avoid fermentation that attracts pests.
  • Clean behind and under equipment to get rid of organic buildup and spilled fruits or vegetables that often go unnoticed. Pay special attention to machine voids, dead-end spaces and footing.
  • Sweep and mop regularly and perform a deep cleaning regularly. Pests are attracted to food odours, so clean up spills immediately.
  • Fit trash containers with a tight-fitting lid and take out trash regularly.
  • Establish a fly control program in the garbage room or compactor area during the spring and summer. This will prevent fly breeding and knock off population buildup.
  • Employ proper refrigeration – low temperatures slow fly breeding activity.
  • Install pest prevention devices, such as glueboard based fly light traps to intercept and control flies.

These tips will not only help you protect your produce from physical pest contaminants but will also indirectly prevent pathogen contamination and food-borne illness. For maximum protection, you should also establish an ongoing pest management program that includes these three steps:

  1. Assess: Work with a pest management provider to assess your facility for existing and potential pest pressures and any conditions that create ideal environments for pests, like moisture, overlooked food sources, overgrown tree branches or weeds, structural deficiencies, poor storage and housekeeping practices and actual signs of pests (droppings, burrows, etc).
  2. Implement: Cookie-cutter pest management programs are less effective than those that are customized to your property. Your pest management strategy should include preventive strategies like proper sanitation and good manufacturing practices (GMPs). Your first line of defence is non-chemical techniques. A combination of preventive measures and non-chemical strategies will effectively keep pests off the facility with minimum use of pesticide products.
  3. Monitor: Pest pressures can change over time, so make sure you are regularly monitoring for pest activity and taking note of any changes or trends. Establish protocols for your staff to report pest sightings so that you can effectively communicate with your pest management provider.

While food-borne illnesses can stem from a variety of sources, a buttoned-up pest management program will help reduce the risk of product contamination. Proactive pest management will also help you rest assured that you are doing everything you can to protect the produce harvested and stored on your property from pest-related pathogens. As they say, an ounce of prevention is worth a pound of cure.

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