Protect perishable products from package insects.

Developing new ways to keep insects out of food in packages, warehouses and processing plants is critical for food manufacturers. New and innovative methods are needed because the industry is challenged to reduce pesticide use while ensuring that food products are insect-free.

To meet these challenges, a team of USDA-ARS scientists at the Grain Marketing and Production Research Center (1515 College Ave., Manhattan, KS 66502) are working closely with industry to keep bugs out of packaged goods. In the late 20th century, the most popular materials for preserving food were aluminum foil, cellophane bags and plastic. Today, restrictions on pesticide use and having fewer sanitation personnel at various points along the distribution chain have made insect-resistant packaging even more important to consumers and to food or feed manufacturers.

ARS entomologists have conducted packaging studies on a variety of products, including cereals, raisins, baby foods and dry pet foods. They classify insects as either invaders, which enter through existing openings, or penetrators, which can chew through packaging materials. Simply using a different glue pattern in the seals and closures of bags can help safeguard the product from insects. A glue pattern that forms a complete seal with no channels for insects to crawl through can help prevent insect entry into a package. Another technique involves using tightly fitting overwraps to increase resistance to invasion.

But packaging is just one defense. In flour mills and food processing plants, insects that survive an insecticide treatment could live on food or crumbs left by poor sanitation. These surviving insects may become resistant to insecticides, making it harder to eliminate the infestation and prevent economic damage. As an alternative to insecticides, researchers are testing insect growth regulators (IGRs), chemicals that prevent insect larvae from becoming reproductive adults. To replicate food-storage conditions, they create exposure arenas by pouring concrete into petri dishes. These test arenas are used to study insect survival after exposure to IGRs and various insecticides. The chemicals are sprayed directly onto the concrete, and insects are exposed to the treated surfaces.

IGRs aren't toxic to humans, and they can suppress populations of important stored-product insect pests such flour beetle. Researchers recently evaluated a volatile formulation of the IGR hydroprene to control two species of flour beetles. In laboratory tests, larvae of both beetle species exposed to the IGR often failed to molt to the adult stage. Adult insects that did emerge were usually deformed and died quickly.

Further information. Michael Mullen; phone: [phone]; fax: [phone]; email: [e-mail].