Discard Spoiled Canned Foods Safely

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Pamela Schmutz, Home & Garden Information Center
Angela Fraser, Extension Food Safety Specialist

As canning foods at home increases in popularity, it is important for home food preservers to know what to do if a jar of food spoils or was improperly processed. Foods must be processed properly to kill bacteria that cause foodborne illness. High-acid foods like fruits and jams must be processed in a water bath canner to prevent molds and yeasts from spoiling them. Low-acid foods, such as vegetables, meats and seafood, must be processed in a pressure canner to prevent the formation of the deadly toxin that can cause botulism.

Canned Foods with Signs of Spoilage
Don’t taste or use canned foods that show any sign of spoilage! Look closely at all jars before opening them. A bulging lid or leaking jar is a sign of spoilage. When you open the jar, look for other signs such as spurting liquid, an off-odor or mold. Spoiled canned foods should be discarded in a place where they will not be eaten by humans or pets.

All suspect containers of spoiled, low-acid foods, including vegetables, meat, seafood and tomatoes, must be treated as having produced the toxin that causes botulism and handled carefully in one of two ways:

  • If the jars or cans are still sealed, place them in a heavy garbage bag. Close and place the bag in a regular trash container or bury it in a nearby landfill.
  • If the jars or cans are unsealed, open or leaking, they should be detoxified before disposal.

Improperly Canned Low-Acid Foods
Improperly canned, low-acid foods can contain the toxin that causes botulism without showing signs of spoilage. For this reason, jars of foods that have not been properly processed must be discarded, or if they are unsealed, open or leaking, they must be detoxified and discarded as explained above, even if there are no signs of spoilage. Low-acid foods are considered improperly canned if any of the following are true:

  • The food was not processed in a pressure canner. (Make sure you have a pressure canner and not a pressure cooker. Small pressure cookers are not intended for use as pressure canners and may not process foods safely.)
  • The gauge of the canner was inaccurate. (Dial-gauge canners must be checked for accuracy every year. Contact your local Extension office to have your gauge checked.)
  • Up-to-date researched processing times and pressures were not used for the size of the jar, style of pack or kind of food processed.
  • Proportions of ingredients were changed from the original approved recipe.
  • The processing time and pressure were not correct for the altitude at which the food was canned.

How to Detoxify Canned, Low-Acid Foods
Contact with botulinum toxin can be fatal whether it is ingested or enters through the skin. Be extremely careful not to splash or come in contact with the suspect food or liquid. Wear disposable rubber or heavy plastic gloves. Wear clothes and aprons that can be bleached or thrown out if contaminated.

Step-by-Step Instructions for Detoxification:

  • Carefully place the jars, with their lids, on their sides in an 8-quart, or larger pot or canner.
  • Wash your gloved hands thoroughly.
  • Carefully, without splashing, add enough hot water to the pot to completely cover the jars with at least 1 inch of water above the containers.
  • Place a lid on the pot and heat the water to boiling. Boil for 30 minutes to make sure the food and containers are detoxified.
  • Cool and discard the containers, their lids and food in the trash or dispose in a nearby landfill.

How to Clean Up Contaminated Surfaces:

  • Wear rubber or heavy plastic gloves to clean up contaminated work surfaces and equipment, including can openers and clothing that may have come in contact with suspect foods or liquids.
  • Use a fresh solution of 1 part unscented, liquid, household, chlorine bleach (5 to 6% sodium hypochlorite) to 5 parts clean water.
  • Spray or wet contaminated surfaces with the bleach solution and let stand for 30 minutes. Avoid inhaling bleach or contact with skin.
  • Wipe treated spills with paper towels and place paper towels in a plastic bag before putting them in the trash.
  • Apply the bleach solution to all surfaces and equipment again, and let stand for 30 minutes and rinse.
  • Wash all detoxified counters, containers, equipment, clothing, etc.
  • Discard gloves when cleaning process is complete.


  1. Reynolds, Susan and Paulette Williams. So Easy to Preserve. Cooperative Extension Service, University of Georgia. Revised 2006 by Elizabeth Andress and Judy Harrison.
  2. USDA. 2009 Complete Guide to Home Canning.

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