Based on the photos that are turning up in some of our social media feeds, many Idahoans are already starting to harvest produce from gardens. Canning is a great way to preserve it and share it with family and friends, but it can be risky if it’s not done correctly. If you plan to can your harvest and share it with family and friends, it’s important to be knowledgeable about proper techniques so you can make sure your home-canned vegetables aren’t contaminated by the germ that causes botulism.

What is botulism?

Botulism is a rare but serious illness caused by a bacteria that produces powerful toxins that can lead to serious illness and paralysis, and even death. The bacteria produce hardy spores that can survive in soil. Fruits, meats, fish, and vegetables could be contaminated with the bacterial spores before they are canned. The spores can survive, grow as bacteria, and produce toxins in jars of food that are not properly canned. It can be deadly to take even a small taste of food that has this toxin in it.

How do people get botulism?

Home-canned vegetables are the most common cause of foodborne botulism outbreaks in the United States. Other food-related outbreaks have been documented from commercially canned products, but those cases are rare.

What are the symptoms of botulism?

Symptoms may include double or blurred vision, drooping eyelids, slurred speech, difficulty breathing or swallowing, dry mouth, and muscle weakness with paralysis. Symptoms generally start anywhere from 8 to 36 hours after eating contaminated food. Call 911 or get to an emergency room as soon as possible if you see signs of this disease. Prompt treatment drastically reduces the risk of death and long-term health problems.

Are there ways to tell if a jar of food might be contaminated?

It may be difficult to tell from the container if the food inside is contaminated with the toxin that causes botulism, but sometimes there are clues that something is wrong. If the container is leaking, bulging or swollen, or it looks damaged or cracked or abnormal in any way, don’t eat the contents. If it squirts liquid or foam when you open it, throw it away, and then wipe up the spill using a solution of a quarter cup bleach for each 2 cups of water. The toxin can be absorbed through the skin, so always wear waterproof gloves to protect yourself if you must touch potentially contaminated contents. Finally, if the food is a funny color, or is moldy, or smells bad, don’t eat it. When in doubt, throw it out!

What’s the best way to be sure you haven’t contaminated your canned foods?

The University of Idaho extension strongly recommends following recipes for canning. Otherwise, make sure you are using modern preservation techniques and the right equipment for the kinds of foods you are canning. You should use a pressure canner or pressure cooker and be sure the gauge on it is working properly. Pay special attention to the processing times for low-acid vegetables such as green beans, carrots, and corn. The USDA, CDC and the U of I extension offices all have useful, step-by-step information about canning on their websites.

A Closer Look at Your Health airs weekly on KBOI Radio 670 in Boise; this is a transcript of the July 24, 2018 program. 

Resources

• Home canning and botulism from the CDC
• National Center for Home Food Preservation information on canning
• FAQ from U of I Extension
• U of I brochure: Targeting Safety When Preserving Food