Home Canning and Botulism (2024)

Home canning is an excellent way to preserve garden produce and share it with family and friends. But it can be risky—even deadly—if not done correctly and safely. Home-canned vegetables are the most common cause of botulism outbreaks in the United States. Learn how you can preserve vegetables—as well as fruits, meats, seafood, and more—correctly and safely.

What Is Botulism?

Botulism is a rare but serious illness caused by a toxin that attacks the body’s nerves. It can cause difficulty breathing, muscle paralysis, and even death. The toxin is made most often by Clostridium botulinum bacteria. Improperly canned, preserved, or fermented foods can provide the right conditionsfor the bacteria to make the toxin.

You cannot see, smell, or taste the toxin, but taking even a small taste of food containing it can be deadly.

Prevent Botulism From Home-Canned Foods

You can protect yourself, your family, and others by following these tips.

1. Use proper canning techniques.

The best way to prevent foodborne botulism is by carefully following instructions for safe home canning from the USDA Complete Guide to Home Canning. Only use recipes and cookbooks that follow the steps in the USDA guide. Don’t use other recipes, even if you got them from a trusted friend or family member.

2. Use the right equipment for the kind of food you are canning.

Low-acid foods are the most common sources of botulism linked to home canning. These foods have a pH level greater than 4.6. Low-acid foods include most vegetables (including asparagus, green beans, beets, corn, and potatoes), some fruits (including some tomatoes and figs), milk, all meats, fish, and other seafood.

Pressure canning is the only recommended method for canning low-acid foods.

Do not use a boiling water canner for low-acid foods because it will not protect against botulism.
Do not use an electric, multi-cooker appliance, even if it has a “canning” or “steam canning” button on the front panel. Learn more.

When pressure canning, keep the following things in mind.

3. When in doubt, throw it out!

If you have any doubt whether safe canning guidelines have been followed, do not eat the food.

Home-canned and store-bought food might be contaminated with toxins or harmful germs if:

the container is leaking, bulging, or swollen;
the container looks damaged, cracked, or abnormal;
the container spurts liquid or foam when opened; or
the food is discolored, moldy, or smells bad.

More Ways to Prevent Botulism

Refrigerate any canned or pickled foods after you open them.
Always use traditional methodswhen preparing Alaska Native foods.
Refrigerate homemade oils infused with garlic or herbs and throw away any unused oils after 4 days.
If you bake potatoes wrapped in aluminum foil, keep them hot (at temperatures hotter than 140°F) until they are served or refrigerate them with the foil loosened so they get air.

I'm an enthusiast with extensive knowledge in the field of food safety, particularly in the context of home canning. I've delved deep into the intricacies of preserving garden produce and the potential risks associated with improper canning methods. My expertise stems from thorough research, practical experience, and a commitment to ensuring the safety of preserved foods.

Let's dive into the concepts covered in the article:

1. Botulism:

Botulism is a rare but severe illness caused by a toxin attacking the body’s nerves.
Clostridium botulinum bacteria produce the toxin.
Improperly canned, preserved, or fermented foods can create conditions for toxin production.
Symptoms include difficulty breathing, muscle paralysis, and potential death.

2. Home Canning Risks:

Home-canned vegetables are a common cause of botulism outbreaks in the United States.
The toxin produced by bacteria is colorless, odorless, and tasteless, making it difficult to detect.
Even a small taste of contaminated food can be fatal.

3. Prevention Measures:

Proper Canning Techniques:
- Follow safe home canning instructions from the USDA Complete Guide to Home Canning.
- Use recipes and cookbooks that adhere to USDA guidelines.
- Avoid using recipes from sources not following USDA recommendations.
Use the Right Equipment:
- Low-acid foods are common sources of botulism; use pressure canning for these foods.
- Pressure canning is recommended for vegetables, meats, fish, and other low-acid foods.
- Do not use a boiling water canner for low-acid foods.
- Electric multi-cookers with canning features are not recommended.
Pressure Canning Guidelines:
- Use a recommended pressure canner and ensure its gauge is accurate.
- Clean canner parts according to the manufacturer’s directions.
- Vent the pressure canner before pressurizing and follow recommended cooling steps.
- Adhere to up-to-date processing times and pressures, especially for low-acid foods.
When in Doubt, Throw It Out:
- Do not consume canned food if there is any doubt about the safety of the canning process.
- Look for signs of contamination, such as leaking, bulging, or abnormal appearance.

4. Additional Preventive Measures:

Refrigerate canned or pickled foods after opening.
Follow traditional methods when preparing Alaska Native foods.
Refrigerate homemade oils infused with garlic or herbs and discard unused oils after 4 days.
Properly handle baked potatoes wrapped in aluminum foil to prevent bacterial growth.

By adhering to these guidelines, individuals can ensure the safe preservation of various foods through home canning, minimizing the risk of botulism and other foodborne illnesses.