The COVID-19 pandemic appears to have sparked a renewed interest in canning as Americans spend more time at home. While canning can be a good way to preserve food for future use, it’s critical to take steps to prevent botulism.
What is botulism?
Botulism is a rare but potentially deadly illness caused by a toxin produced by certain germs, most notably the bacteria Clostridium botulinum. Foods that have been improperly canned, preserved or fermented are among the most commons sources of this toxin, which affects the nervous system.
Low-acid foods are more likely to contain this poison when they are not preserved in the right way. Some examples are:
- Asparagus
- Beets
- Corn
- Green beans
- Mushrooms
- Potatoes
- Spinach
- Some tomatoes
- Meats
- Fish and seafood
You cannot see, smell or taste the toxin, making prevention essential.
While foodborne botulism is not common, it can be fatal if it is not caught early and treated effectively.
What are the symptoms of botulism?
Symptoms typically appear 12 to 36 hours after exposure, but can begin as early as 6 hours after or as long as 10 days later.
Early symptoms often include nausea or stomach ache, sometimes with constipation.
The effects on the nervous system usually begin in the head and face. Symptoms can include:
- Blurred vision
- Drooping eyelids
- Dry mouth
- Trouble swallowing and speaking
The illness can go on to cause muscle weakness, including in your arms and legs and in the muscles used to breathe, making breathing difficult.
How can I prevent botulism?
The best way to prevent foodborne botulism is by carefully following the instructions in the USDA’s Complete Guide to Home Canning. We recommend taking a canning or food preservation course with your local university extension, as well.
When canning low-acid foods, it is important to use a pressure canner, according to the CDC. Do not use an electric, multicooker appliance, even if it has a canning button. It is unclear if these are effective in preventing botulism. Carefully follow the processing times given in the USDA guide.
Pay close attention to your cans when you are ready to open them. Throw out any canned food—whether it’s store bought or home canned—if it is leaking or bulging or if it looks damaged or cracked. Throw out the food if the container spurts liquid or foam when you open it or if the food is discolored or smells bad.
Store any opened canned or pickled foods in the refrigerator.
The CDC recommends caution when you are throwing out possibly contaminated food. Use rubber or latex gloves before you handle it. Put the food in a sealable plastic bag, then wrap another plastic bag around it and tape it shut. Place the bags in a trash receptacle outside the house. Use a bleach solution to wipe up any spills. Wash your hands with soap and water for at least two minutes afterwards.
What should I do if I think I have botulism?
If you are showing signs of botulism, contact the poison center right away. The poison center’s experts can tell you what steps you need to take immediately and direct you to the best place for further care. Call us at 1-800-222-1222, chat with us online or text POISON to 85511.
