Return to Food Safety
Where do they come from?
Modern food processing and packaging methods virtually preclude the
possibility of insect infestation at the plant level. When merchandise is
shopped from a plant, it may go through several channels of distribution before
it reaches its final destination. Sometimes, goods may be exposed to infestation
in transit or storage and the result will not be known until it is used by the
Infestation can also occur right in the home. Sometimes insects infesting
other foods in the cupboard come from unsuspected sources. Food products that
are left undisturbed on shelves for 5 to 8 weeks are particularly susceptible to
pests, especially in warm, humid weather.
There are many types of insects that attack foods. Some in the larva or adult
stage can bore their way into a tightly sealed package. Entrance holes are
normally small and difficult to see. Products packaged in glass containers are
less likely to become infested. The insects can, however, follow a path up
through the screw-on guides under the jar lid and make their way to the top. If
this happens, the insect may be discovered between the seal and cap, or possibly
in the product itself.
Controlling and Preventing
Follow these steps when food is infested:
- Locate source of infestation. Check seldom-used packages of cereal, flour,
raisins and spices. Check dry dog and cat food and bird seed.
- Wrap heavily infested food in heavy plastic bag and immediately dispose of
it away from all other foods.
- Heat or freeze susceptible foods after you have had them for 60 days, even
if they do not appear infested. Cold treat packaged foods such as cake mixes and
spices in their original containers. Expose them to 0 degrees F. or lower
temperatures for 3 days or 7 days for larger packages.
- Store insect-free foods in tightly closed glass, metal or heavy plastic
- Periodically clean pantry and cupboard shelves, particularly cracks,
crevices and spaces under shelves. A vacuum cleaner works best.
- The use of insecticides has no effect on insects within food packages.
Follow these steps to prevent future infestations:
- Avoid long storage periods by purchasing susceptible or seldom used foods in
- At time of purchase, examine foods such as cornmeal, coarse cereals and
macaroni to be sure they are insect free.
- Store susceptible foods in insect-proof containers.
- Heat-treat or cold-treat dried foods that you store for more than 60 days.
- Check dry dog and cat food and bird seed often for insects.