Bread dough in production line

Food dust in processing plants: a constant battle

Pari Pachamuthu

No matter how spotless a food processing facility appears to be, high-flying and low-lying food dust warrant several causes for concern. If allowed to accumulate, this dust not only poses a safety hazard, it can also compromise the integrity of the grains being processed—providing an excellent food source for stored product pests (SPP) to breed.

Stored product pests in food processing facilities

Food plants processing flour, grain, dairy and pet foods are among the most commonly affected by SPP. According to Rentokil data from 2017 and 2018, SPP rank among the top 5 pests for food processing plants in every month of the year. Due to consistently warm temperatures in plants, SPP are active all year and in all states. Therefore, it is critical to take the appropriate steps to inspect all areas, especially hard to reach places. You can clean at floor level, but there is dust on high beams that you’re not going to see, which is a source for an infestation. Even food processing plants with dust collectors will experience some dust accumulation in cracks and crevices throughout the plant. And, if not cleaned out regularly, the catchers on the dust collectors themselves provide an excellent source for an SPP infestation. The following areas listed below also collect dust and should be inspected on a monthly basis.

Stored product pest infestation sources:

  • Wall voids
  • Conveyor belts within enclosed systems
  • Kick plates
  • High beams
  • Electrical conduits, pipes, ductwork
  • Dust collection systems
  • Cracks and crevices of production floors
  • Food processing equipment
  • Gaps/holes in walls, ceilings, floors

Implementing integrated pest management for stored product pests

Implementing an Integrated Pest Management (IPM) approach is the best proactive prevention measure for SPP infestations. IPM will consider internal and external risks, as well as the most effective treatments for preventing and eradicating an SPP infestation. Additionally, it examines how the plant’s daily operations will be affected, especially any downtime.

Treatments target the biology of SPP – life cycle, egg capacity, adult stage. For instance, pheromone traps are replaced based on how long the SPP life cycle lasts. This may be every two to three months or adding an insect growth regulator (IGR) to target the larval stage.

SPP Life Cycle (days) Egg Capacity Adult Stage
Indian meal moth 21-60 200-400 7-10
Cigarette beetle 26-90  30-42 7-30 days
Drugstore beetle 40-210 75 13-85 days
Red flour beetle 20-30  200-450 6-18 months
Confused flour beetle 28-52 200-500 6-12 months
Warehouse beetle 32-50 100 8-58 days

In addition to the biology of the insect, you should also consider how the product is being stored. Are there are any external factors such as vendors or surrounding businesses that may contribute to an SPP infestation? Live insects and/or webbing on or around product is a good indication that there’s an infestation. 

Preventing dust and inspecting areas where it can settle is instrumental to a successful pest management partnership. IPM identifies the risks of the facility by monitoring for pest activity, documenting housekeeping, and assessing sanitation conditions. Partnering with a professional pest control company that will inspect your facility, inside and out, is sometimes the best way to circumvent a costly infestation.

Stack of white bags at warehouse

Integrated pest management strategies

Once a food processing plant is fully inspected, inside and out, one of the following IPM strategies – focusing on prevention, intervention, or both – may be used:

  • Pheromone traps – Used for monitoring SPP activity (specifically Indian meal moths) to indicate where there is concentrated activity.
  • Mating disruption system – Releases large amounts of pheromones, confusing males and limiting their ability to successfully mate with females due to their short lifespan.
  • Insect light traps – Useful to control and monitor SPP. However, not all SPP are attracted to insect light traps. Speak to your Rentokil Specialist to see if the LED-powered, energy-saving Lumnia product range is a viable solution.
  • Pesticide applications – If necessary, pesticides may be applied in the form of liquids, dusts, fogs, or fumigations.
  • Controlled temperatures – Hot and freezing temperatures are effective for treating contaminated products when fumigants are not able to be used.

pyramid representation of pest management solution decision

Tips for preventing stored product pest infestations

  • Store food product pallets off the floor (at least 18 -24 inches from the wall, 6 inches off the floor and 6-12 inches between bay rows.)
  • Rotate stock following First In, First Out product rotation practices. This ensures nothing sits on the shelves for long periods of time, reducing the risk of an SPP infestation.
  • Schedule an annual deep cleaning of the facility, paying special attention to SPP infestation sources (high beams, conduits, machinery, flooring, etc.)

Regulatory compliance

To be in compliance with the Food Safety Modernization Act, your program must address the specific risks at your facility – these risks may be based on the products you produce, specific pest pressures in your area, your facility’s structure, and more. You should evaluate your pest risk continually, and especially if your facility introduces a new process, undergoes significant structural changes, or begins processing new ingredients or products.


Rentokil can help you design a comprehensive pest management strategy that addresses your facility’s unique risks. To speak with one of our experts, call us today at 800.488.9495 or visit our site and use our Live Chat feature.

Pari Pachamuthu
Pari Pachamuthu

Pari Pachamuthu is a board-certified entomologist and the technical director for Rentokil Steritech’s Central Market. He is an expert in detecting and treating stored product pests in food manufacturing facilities and other commercial settings.

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