Canning your garden harvest 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. I know it’s early yet, but harvest time will be here before we know it, and it’s important to be knowledgeable about proper canning 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, including 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 canning. The spores can survive, grow as bacteria, and produce toxins in improperly canned jars of food. It can be deadly to take even a small taste of food that has this toxin in it. 

How do people get botulism?

Botulism infections generally fall into three categories; foodborne botulism, which we are talking about today, infant botulism, and wound botulism. Home-canned vegetables are the most common cause of foodborne botulism outbreaks in the United States. From 1996 to 2010, there were 210 outbreaks of foodborne botulism reported to the Centers for Disease Control and Prevention. Of the 145 outbreaks that were caused by home-prepared foods, 43, or 30 percent, were from home-canned vegetables. Other food-related outbreaks have been documented from commercially canned products.

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. They generally start anywhere from 8-36 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 can or jar if it is contaminated with 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 avoid exposure to the toxin 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?

You can use modern preservation techniques and the right equipment for the kinds of foods you are canning. You should use a pressure canner or cooker and be sure the gauge on it is working properly. Pay special attention to the processing times for low-acid vegetables like green beans, carrots, and corn. The USDA, CDC and county extension offices all have useful, step-by-step information about canning on their websites.

(Note: A Closer Look At Your Health airs at 6:50 a.m. most Tuesdays on KBOI News Radio 670. This is the segment that aired this morning, July 12.) 

Resources

• Home canning and botulism from the CDC
• USDA Complete Guide to Home Canning
• FAQ from U of I Extension