Detoxifying Canned, Low-Acid Foods

The following question from a Canning Coach is the inspiration for today’s Canning Tip.

“A friend of ours stopped in today to ask about exploding cans of food. Apparently he had a can of yams in the cabinet that exploded. His first question was what caused it to explode. The second was how to clean up everything to make sure the surrounding cans are safe to open. I’m assuming it was botulism. I really don’t know the answers to his questions. Would bleach work?”

My response to the Coach’s question was “It is a safe assumption that botulism toxin is present in the exploded can of yams.” Canned yams are low-acid foods that will support growth and toxin formation by Clostridium botulinum. It is critically important to inactivate any potential toxin. HGIC fact sheet 3040 “Canning Foods at Home” provides step-by-step directions for destroying the toxin that causes botulism in canned low-acid foods.
Please note that 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 and avoid 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.

Canning Coach Tips are distributed to help you answer questions that arise when friends and neighbors look for ways to safely preserve and store high quality South Carolina foods. Tips are distributed monthly. Please send suggestions for future tips.

Source: HGIC fact sheet 3040 “Canning Foods at Home”