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Extension > Food > Food Safety > Preserving and Preparing > Storage > Insect Pests of Stored Foods

Storage

Insect Pests of Stored Foods

By Jeffrey Hahn, Extension Entomologist — Horticulture

Revised 2011 by author.

English | Spanish

It is a very common problem for insects to get into dried food that is stored in the home. These insects are often called "pantry pests." They ruin more food than they eat, since most people will not eat food once they find insects in it. Pantry pests are often found when they leave the food they have invaded to crawl or fly around the home. They often collect in pots, pans, or dishes, or on windowsills. Fortunately, these kinds of insects do not bite or sting people or pets. They do not damage the home structure or eat wood.

What do these insects eat?

These insects eat almost any kind of dried food. Here are some examples:

Grains

  • flour
  • cake mix
  • cornmeal
  • rice
  • spaghetti
  • crackers
  • cookies

Seeds

  • dried beans
  • popcorn
  • ornamental corn and seed
  • garden seeds
  • bird seed

Other

  • spices
  • powdered milk
  • chocolate
  • dried plant displays
  • potpourri
  • rodent baits
  • dry pet food

Where do these insects come from?

Sometimes insects get into dried food at a processing plant or warehouse, while it is being shipped to a store, or at a store. Insects may also get into food in your own home. Though insects can get into food of any age, the longer it is stored, the more likely it is that insects will get in it.

Pantry pests are most likely to appear in opened packages of food. But they can break through unopened paper, thin cardboard, plastic, foil, or cellophane. Once they are in your food, these insects can begin to multiply and spread to other dried food. These insects may also begin to feed on bits of food in the corners, cracks, or crevices of your cupboard.

How can I keep insects from getting into my dried food?

  1. Buy dried food in small quantities so it does not sit on the shelf too long.
  2. Look carefully before you buy food in packages or bulk quantity. Make sure packages are sealed and that there are no holes in the packaging or wrapping. Do not buy any food past the freshness date stamped on the package.
  3. Keep food, especially food that takes longer to use, in tightly closed glass, metal, or heavy plastic containers with tight lids.
  4. You can also refrigerate any food that is likely to get insects in it.
  5. Wipe up crumbs and spilled food to keep food storage areas clean.

If I find insects in my food, how do I get them out?

  1. Throw away or sterilize all food that has insects in it.
  2. If you want to try to save the food you may place the food in the freezer at 0 degrees for at least 4 days. Or you can heat your oven to 130 degrees and heat the food in a shallow pan for at least 30 minutes to kill any insects, eggs, or larvae.
  3. Empty and thoroughly clean cabinets, especially cracks and corners, with a vacuum cleaner. Empty the vacuum cleaner or throw away the vacuum cleaner bag after you have cleaned, so the insects don't re-enter.

Please note that these methods will not work to get insects out

  1. Leaving bay leaves or sticks of spearmint gum in your cupboards. These will not keep insects away.
  2. Picking out the insects and restoring the food without heating or freezing it first (see #3 above). The insect eggs and larvae will still be in the food, so insects will continue to grow and spread.
  3. Using insecticide sprays in cupboards. Spraying insects that you see crawling on counters or in cupboards does not prevent more from coming from infested food. You cannot spray food that has insects in it because you will poison the food. Only throwing away food that is infested will work.
  4. Washing cupboards with detergent, bleach, ammonia, or disinfectants. You must vacuum to get rid of the insects.
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