One of the biggest risks in food storage and processing facilities is pests, particularly insects. Insects, or pantry pests, are often drawn to powdered goods and dried foods like beans, nuts, flour, cornmeal, cured meats, pet food and seeds. While insect dangers are most prominent in powdered goods with opened packaging, pests are capable of penetrating unopened packages made of thin cardboard, paper, cellophane, plastic and foil. By knowing which insects are most likely to contaminate dried food products, you can take steps to effectively prevent and control an infestation.

Moisture Attracts Insects
Pests seek sources of food, water and shelter. Access to a food source alone, such as spilled food, is enough to draw the attention of insects. Because most powdered goods are in enclosed environments, such as warehouses, this satisfies a pest’s need for shelter. Adding moisture to the mix—whether it’s high humidity levels, leaks or spills—provides everything an insect needs to survive and reproduce.
In addition, moisture sometimes attracts insects because of its affect on powdered and dried foods. When exposed to humid conditions, food begins to deteriorate and grow molds that some insects eat. The mold not only spoils the affected food, it also puts the other stored goods at risk of an infestation.
Insects Commonly Found in Dry Food Products
- Black carpet beetle (Attagenus unicolor): A serious household pest, black carpet beetles are dark brown and 3 to 5 millimeters long. In nature, they eat pollen. In buildings, the beetles eat protein-rich dry goods, such as pet food. The more access to water that female beetles have, the more eggs they lay.
- Cigarette beetle (Stegobium panicum): About 1/8-inch in length, cigarette beetles are brown, fly, have an oval body covered with fine hairs, and have a humped appearance. The bugs feed on a variety of dried goods, such as pasta, spices, grains, flowers, tobacco and even paper.
- Foreign grain beetle (Ahasverus advena): A small insect that’s 2 to 3 millimeters long, foreign grain beetles are reddish brown and can fly. They are scavengers that feed on moldy grains, fungus and dead insects. They live in environments where fungus and moisture problems exist, even when powdered goods are not infected with mold. Preventing and controlling foreign grain beetles involves eliminating moisture, fungus and mold in a property, as well as contaminated foods.
- Indian meal moth (Plodia interpunctella): The most common type of moth to infest food products, indan meal moths have a wingspan of ½ to 5/8 inch. The tops of the wings look as if they have light and dark brown strips with shimmery, coppery finish. The moths eat dried foods, including pet food, birdseeds, fish food, dried fruit, grains, cereals and herbs. They leave silk webbings on the surfaces of food products.
- Psocids: This primitive order of insects, considered parasitic lice, includes over 5,500 species. They range between 1 and 10 millimeters in length. The species found in dried foods primarily feed on fungi caused by high moisture levels. The booklice variety feed on dry starchy materials.
- Red flour beetle (Tribolium castaneum): There are several types of flour beetles. Reddish brown in color, red flour beetles fly and are between 3 and 4 millimeters long. The insects prefer to eat flour and cereal products, and often infest mills and food processing plants. The red flour beetle is originally from Asia and predominantly lives in southern U.S. states. When the insect infests grains, females lay their eggs in the dry goods. It may take several months for the eggs to hatch. In warm, moist environments, there can be as many as five insect generations per year.
- Warehouse beetle (Trogoderma spp): Also called cabinet beetles, warehouse beetles are oval-shaped and 1/8 to 3/16 inch long. Their bodies may appear black or speckled with black, yellow and red marking. The insects eat a variety of dried goods, including pet food, dry fruit, seeds and grains. They also feed on hair, fur and dead skin.
The keys to preventing insect dangers in powdered goods include storing food products in airtight, lidded containers in dry areas. However, it isn’t always possible to repackage food, particularly when storing them in large quantities. When this is the case, it’s best to store the goods in a dry environment to reduce the risk of insect infestations and mold growth. Supplementing a building’s HVAC system with Polygon’s custom humidity control solutions help create the ideal environment for food storage. When a facility is dry and clean, it is less likely to attract pests. Get in touch with Polygon today to learn more about humidity control for your dry goods.
[Photo from Phu Thinh Co via CC License 2.0]