By James Bond

Winter is not typically considered a high pest activity season, as outdoor pests are generally more active during the warmer months. However, for some parts of the country, winter pest control can be a difficult task. In addition to the normal pest pressure of a food processing or storage facility, these facilities will have outdoor pests seeking warm shelter when the weather turns cooler. So, to maintain an integrated pest management (IPM) program, adjustments need to be made based on factors such as neighboring businesses, elevation, and local climate. Following are some principles to follow to ensure your facility is “winterized.”

MAKING IPM ADJUSTMENTS. With fall being a traditional time for farmers to harvest crops in many areas, the activity can disrupt the feeding and shelter of field mice, insects, and other pests, and cause an increased pressure on any nearby food facility, which will extend into winter if steps are not taken. One step which can be helpful is increasing the frequency at which exterior bait stations and internal traps are checked to offset the elevated pest pressure. Once it is determined that populations have decreased, the frequency of checking of traps and bait stations can return to normal.

Some facilities choose to stop checking exterior bait stations during the colder months altogether, particularly those stations that become inaccessible due to snow. Ironically, unchecked bait stations may become shelters for mice during the winter months. Snowfall does not necessarily mean rodent activity will decrease. In fact, snow can act as an insulated blanket, and can keep mice warm in nearby fields. Thus, the risk to each facility will need to be evaluated on a case-by-case basis.

There are also some facilities that turn off their insect light traps during the winter months. But stored pest monitoring devices, such as pheromone traps, should always remain in effect. Additionally, regular inspections of insect-susceptible materials, such as flour and grains, should be conducted on a regular basis no matter the season. Thus, all such activities should remain in effect even though the storage areas may get cooler.

PREVENTION. One of the most effective methods for deterring pest activity is maintaining a fully sealed building. It is a good practice to keep all doors closed whenever possible. Sometimes this requires educating employees on the importance of keeping the doors closed. Even leaving a door open for a two-minute smoke break can be an opportunity for pest ingress.

All other small holes and gaps also should be sealed. If outdoor insects such as worms or centipedes are found at the wall/floor juncture or near support beams, this may indicate that there are small cracks or openings in the floor. Check the floors and walls for moisture and small holes — and seal these areas as they are identified.

Leaving a door open for even a short smoke break can be an opportunity for pest ingress.

In addition to assuring all doors are closed and gaps sealed, you should check the exterior of the facility for harborage areas. Not all holes in exterior walls will penetrate the building; however, these holes could provide spaces where pests find harborage. These areas should be repaired as well.

STRUCTURALLY SOUND. Checking the exterior of the building and making necessary repairs in preparation for winter is certainly easier in the warmer months — particularly in areas where the ground turns hard due to frost. However, if this was not done in the fall, it is advisable to do an exterior inspection and make repairs as soon as possible.

Some buildings have “heaving” issues during the winter months. This is due to moisture in the ground freezing and expanding. This can warp doors and door frames, create cracks in the floor, and cause damage to walls. It’s important to assure these issues are addressed as soon as possible. Monthly self-inspections should identify these issues as they occur, and potential ingress points should be sealed when they are identified.

Moisture and frost in the winter months also can compromise the integrity of the roof. Damage to the roof and other structures, such as bucket elevator legs, can cause leaks into production and storage areas. Additionally, over time, pest ingress points could develop. Make sure all bucket elevator legs have no holes or gaps and are fully sealed. Some roofing materials are better than others, and when food safety is a concern, adequate resources must be allocated to assure roof integrity is maintained.

Neglected outbuildings and storage trailers can shelter pests as well. Even when these are located a short distance from the food facility or entrance; there are some pests that are very opportunistic and will seek out and enter open doors whenever possible. Make sure all outbuildings and other structures are inspected on a regular basis — no less than monthly.

Other areas to check are roof structures, such as old HVAC systems, where pests can shelter, and always inspect the ground around the building for burrows or areas where the earth has fallen away from concrete barriers or driveways. When the weather is cold, these areas become less hospitable to pests, and they may put pressure on the building.

Make sure there is no pooling water on the surrounding grounds. Not only is pooling water a pest attractant and nesting area for some outdoor pests, such as mosquitoes, in the warmer months, but if unchecked, pooling water can turn to ice in the winter and cause damage to the exterior of the building. Parking lots, concrete pads, and other areas around the building should slope away from the facility and toward a drain or ditch.

In some areas, migratory birds, such as Canadian geese, can become an issue.
© JonathanNicholls |

Some local ordinances require vegetation to adorn the grounds around a building, but whenever possible, vegetation should be kept to a minimum to eliminate harborage areas. Local city councils can be petitioned for exceptions for food processing and storage facilities. When exceptions cannot be obtained, select trees and bushes which do not provide food or otherwise attract pests.

Additionally, some tree root systems are prone to compromising the integrity of concrete foundations. This can lead to issues over time. If trees must be planted on the facility grounds, select those which are less likely to send secondary shoots into other areas around the facility.

OCCASIONAL INVADERS. Other non-food storage pests may enter production and storage facilities in the colder weather. Amphibians (e.g., frogs) and reptiles, (e.g., lizards) are not typically food storage pests; however, they commonly carry pathogens such as Salmonella and Listeria. The IPM program also should be robust enough to account for these occasional invaders.

In some areas, migratory birds can become a major issue. Canadian geese are a common bird which can leave large quantities of droppings around a facility. These droppings contain pathogenic bacteria which can then be tracked into a food processing facility. There are various deterrent devices which can be used. These devices have weaknesses and strengths, so it is important to use what works best to keep birds away from the facility and surrounding area.

Following are some standard methods of deterring birds:

  • Predatory decoys (e.g., owl, hawk, or even dog silhouettes). The problem with decoys is birds can get acclimated to their presence. One method to prevent this is to keep the decoy in a place that is not constantly visible to the surrounding area, but becomes visible when a bird comes close to a door. Placing decoys in these areas, such as under a receiving bay overhead, can prove to be more effective. Alternately, personnel can regularly re-position the decoy on a set frequency.
  • Predatory calls. These can be particularly effective if they cycle through several different calls, preventing birds from getting acclimated to the same calls.
  • Netting. It’s important that the netting is strategically placed and kept in good repair to prevent birds from getting through holes and subsequently dying within the netting.
  • Spikes. These can be effective in deterring some types of birds; however, pigeons are notorious for nesting in longer spikes. Select the spike size that works best for the type of bird in the area.
  • “Screamers.” This is a type of firecracker designed to scare birds. These can be very effective over time. The drawback is that they may not be permitted in some commercial or industrial areas. Check with the local regulations to see if a permit to use them is required.
  • Repellents. There are various sprays on the market which can be used to deter bird activity. Many of these are made of grape-seed extract. Golf courses regularly use these sprays to deter Canadian geese from congregating on the course. Some of these sprays may be effective around the perimeter of the facility. Again, check local regulations to make sure these sprays are allowed to be used in the area.

As mentioned, appeals may need to be made to local city councils for the use of some bird deterrent methods. This is especially true when it comes to food safety and the health of the public. Note that a city council is a different audience than a plant workforce. Since this is the case, a different approach should be considered to match the message to the audience.

Check the exterior of the facility for harborage areas. Not all holes in exterior walls will penetrate the building; however, these holes could provide spaces where pests find harborage.

EMPLOYEE ENGAGEMENT. It can be easy to become lax in pest control efforts over the winter. But it is important to continue to conduct regular employee training sessions regarding pest control. Make sure employees are aware of the workplace pest control programs. such as the pest-sighting log.

The pest-sighting log should be an active part of the IPM program, not just another page in the pest control logbook. Putting the pest sighting log in a public location such as the breakroom increases the chance that it will be used. Getting creative, such as establishing a “bounty hunter rewards” program, also can help with employee engagement.

Finally, be sure facility personnel and the contracted pest control company are working concurrently. A clearly written contract or service agreement should be signed by both a plant representative and the contracted service provider.

Regular walkthroughs in the plant with the service technician can be helpful as well. At least one member of the management team should be very familiar with the contracted service providers responsibilities. Even if pest management services are contracted, it is ultimately the responsibility of the facility to assure the program is effective.

CONCLUSION. Pest problems are a constant battle with food processing facilities. While winter weather may bring easier conditions to maintain, it also may bring a host of new challenges. As with many aspects of the quality and food safety programs, the pest management program may need to evolve and change as conditions change. Diligence and adequate resources are required to assure the IPM program is successful.

The author is Food Safety Professional, AIB International.