Stored product pests in your food processing facility are more than a nuisance — they can compromise your food products and put a dent in your bottom line.

A study conducted by CEBR found that disruptions due to pest infestations in the global food supply resulted in $9.6 billion in operating costs in the countries surveyed. And 84% of U.S. companies reported a net impact on revenue due to pest infestations over a five-year period. Twenty-eight percent of food manufacturers and processors surveyed indicated that they experienced pest-related costs associated with contamination of raw materials leading to replacement costs.

To make matters worse, without the help of a trained pest management professional these pests can be tough to detect and difficult to control. In fact, according to the U.S. Department of Agriculture and the University of Wisconsin, “In the U.S. alone, stored product pests can damage, contaminate, or consume as much as 10% of the total food produced; in developing countries, that rate has been estimated at 50% or more.”

Having stored product pests in your food processing facility can be quite costly. The best way to prevent them is by continually reviewing and improving your Integrated Pest Management (IPM) program. Evaluate it with your pest management professional at least yearly. Ensure regular inspections of the facility and products are incorporated into the IPM plan and you’ll have a better chance of catching these pests before they negatively affect profits.

Biology of Stored Product Pests

When the term “stored product insects” is used, it refers to a variety of different insects capable of reproducing in foods. These pests are usually tiny and tough to spot, which is why they’re so challenging to locate without the help of a trained professional.

Once they’ve found a way to a food source, many stored product pests are going to set up shop and start reproducing immediately. Now, your goods are contaminated. Then, these pests will start moving from bin to bin, silo to silo, contaminating and feeding on any products they find.

Typically, these stored product pests are categorized as internal or external developers, depending on whether the immature stages develop inside grain kernels, or outside. If contamination worsens and mold or fungal growth begins in or around product, secondary feeders will be attracted and can worsen the already-present problem. Each group of stored product pests has its own characteristics and distinct preferences within the category, so here are a few specific examples worth illustrating.

Once an adult finds a suitable food source (any type of whole grain) they will lay the eggs either on or just inside the kernel. The larvae develop inside the individual kernel of grain, eating the insides until just the outer shell remains. They even pupate inside the kernel. Once they reach the adult stage, they chew a distinctive round exit hole, emerge, and start the process all over again.

The lesser grain borer, one of the most common in wheat in the United States, measures up to just 3 millimeters in length and can fly. They are very mobile and will go from silo to silo or bin to bin, even super sack to super sack. You can spot the damage by looking for those hollowed-out kernels with an exit hole where the borer chewed through.

External developers are a larger group of pests. Unfortunately, they’re big fans of grain-based goods as well. Some are considered scavengers because they eat a wider range of foods, but many external feeders prefer to eat broken and processed grain products. A common species in this category is the Indian meal moth, which is one of the (relatively) larger and easier-to-spot stored product pests. The body of these moths is about 9 millimeters long with a wingspan approximately 15 millimeters across. The adults only live about a week but will lay up to 400 eggs on product, which is the start of an infestation. When present, Indian meal moth larvae leave behind silky-looking webbing and frass on product, which gums up product and equipment. Feeding will damage the grains further and leaves them more vulnerable to secondary mold feeders.

The mold- and fungus-loving group, secondary feeders, can often be present at the same time as other stored product pests. Once internal and external feeders have infiltrated and contaminated product, conditions are ripe for secondary feeders to move in.

Foreign grain beetles are another common pest in this category, and they’re tiny, too. Only about 2 to 3 millimeters in size, these beetles are happy to stay out of sight and thrive in any wet, moldy conditions present. If you have any water damage, moisture buildup, or moldy grain around the facility, you should to remove it immediately.

Prevent, Monitor, Detect and Remove

A trained professional can help correctly identify the species and recommend the best course of action to resolve the issue. But with a team effort from employees, management and your pest control specialist, you can implement the following tactics as part of your IPM program to help in the prevention of stored product pests.

• Inspect incoming shipments — Closely inspect all incoming shipments for live insects, webbing and damaged kernels. These could all be signs of stored product pests. If pests are suspected, take a sample and place in a closed, labeled container to monitor for about a month (the typical time it takes to go from egg to adult) and see if any activity is happening.
• Pheromone traps — The best tool to monitor for stored product pest activity is the pheromone trap. Place them around your facility to get an early warning if these pests are around. They are small and like to hide, so pheromone traps are an extra set of eyes working 24/7 for you. Once placed, these will offer insight as to which areas are most at-risk in your facility for pest problems.
• Check the temperature — Stored products pests cannot thrive in extreme temperatures and can’t develop below 15 degrees C (60 degrees F). When possible, keep grains aerated and cooled. Also, monitor the temperatures inside silos and bins. Hot spots in the grain mass can be an early warning sign of insect activity.
• First in, first out (FIFO) — Deteriorating products are an invitation for stored pests, so remove older and damaged products first. Also, store products 18 inches away from the walls in any warehouse areas. This makes cleaning surrounding areas easier.
• Set a sanitation schedule — The more you can limit the amount and access to food, the fewer insects can get established. Create an ongoing sanitation schedule for employees and define responsibilities relevant to team members’ roles. Divide tasks up between daily, weekly, monthly, and even quarterly duties. Don’t forget to document it all.

You need your whole team on board for the most effective pest management program possible. Team members who work close to equipment should be in charge of inspecting it each day, while forklift operators in charge of moving and placing goods in the storage areas should look for any signs of pest activity. That way, you’ll be able to notice pest issues quickly and notify your pest management professional earlier. That will help mitigate major risk.

Resolving pest issues as quickly as possible will be beneficial in the long run, as infestations are naturally more difficult to remove. Being proactive while working with a pest management provider to create a customized IPM plan will help prevent pests and protect your products, business and bottom line.