Savannah Valley District

Discarding Spoiled Canned Foods Safely

Christine Patrick, County Extension EFNEP Agent

Home food preservers need 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.

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 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
  • The 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

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 of them in a nearby landfill

How to Clean 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, let stand for 30 minutes and rinse
  • Wash all detoxified counters, containers, equipment, clothing, etc.
  • Discard gloves when the cleaning process is complete

If you plan to freeze or can any vegetables this summer, contact your local Clemson University Extension Office for the most up-to-date methods of preservation.

Clemson University Cooperative Extension Service offers its programs to people of all ages, regardless of race, color, gender, religion, national origin, disability, political beliefs, sexual orientation, or marital or family status, and is an equal opportunity employer.