Botulism and Home Canning Botulism and Home Canning
Center for Disease Control and Prevention

Home Canning and Botulism

Home canning is an excellent way to preserve garden produce and share it with family and friends, but it can be risky or even deadly if not done correctly and safely.

Home-canned vegetables are the most common cause of botulism outbreaks in the United States. From 1996 to 2008, there were 116 outbreaks of foodborne botulism reported to CDC. Of the 48 outbreaks that were caused by home-prepared foods, 18 outbreaks, or 38%, were from home-canned vegetables. These outbreaks often occur because home canners did not follow canning instructions, did not use pressure cookers, ignored signs of food spoilage, and were unaware of the risk of botulism from improperly preserving vegetables.

For more information, see Three outbreaks of foodborne botulism caused by unsafe home canning of vegetables–Ohio and Washington, 2008 and 2009.

It’s summer, and home gardeners may already be harvesting—or thinking about harvesting—the delicious produce they’ve been growing this year. Food gardening and home canning are becoming increasingly popular in the United States. According to one survey, 1 in 5 U.S. households can their own food, and 65% of those households can vegetables.

If canning is done improperly, the vegetables you worked so hard to grow, harvest, and preserve could become contaminated with germs that cause serious illness. In fact, a study shows that many home canners are not aware of the risk of botulism, a rare and potentially fatal foodborne illness that has been linked to improperly canned food. By knowing about the risks and learning the safe way to can, you can protect yourself, your family, and others when you share your home-canned goodies.

Botulism, rare but deadly

Botulism is a rare, but serious illness caused by a germ called Clostridium botulinum. The germ is found in soil and can survive, grow, and produce toxin in a sealed jar of food. This toxin can affect your nerves, paralyze you, and even cause death. Even taking a small taste of food containing this toxin can be deadly.

Botulism is a medical emergency. If you have symptoms of botulism, seek medical care immediately.

Symptoms of botulism poisoning Adults Double vision Blurred vision Drooping eyelids Slurred speech Difficulty swallowing Dry mouth Muscle weakness Infants Lethargy Weakness Poor feeding Constipation Poor head control Poor gag and sucking reflex

USDA’s Complete Guide to Home Canning

Keep your vegetables safe from contamination

Here are some tips to keep your canned vegetables safe and keep them from spoiling.

Use proper canning techniques

Make sure your food preservation information is always current with up-to-date, scientifically tested guidelines. Don’t use outdated publications or cookbooks, even if they were handed down to you from trusted family cooks.

You can find in-depth, step-by-step directions from the following sources:

The National Center for Home Food Preservation USDA Complete Guide to Home Canning The state and county extension service of your state university Use the right equipment for the kind of foods that you are canning Make your home-canned vegetables safe Use a pressure canner or cooker. Be sure the gauge of the pressure canner or cooker is accurate. Use up-to-date process times and pressures for the kind of food, the size of jar, and the method of packing food in the jar.

Use a pressure canner or cooker. Pressure canning is the only recommended method for canning vegetables, meat, poultry, and seafood. The germ bacterium that causes botulism is destroyed when these foods are processed at the correct time and pressure in pressure canners or cookers. Do not use boiling water canners because they will not protect against botulism poisoning.

Any food that may be contaminated with the germs that cause botulism should be thrown out. If you suspect that you have contaminated food, see "Safely dispose home-canned foods."

Protect yourself from botulism: When in doubt, throw it out! Any food that may be contaminated with the germs that cause botulism should be thrown out. If you suspect that you have contaminated food, see "Safely dispose home-canned foods." Never taste the product to determine if it is safe. Do not taste or eat foods from containers that are leaking, have bulges or are swollen, or look damaged, cracked, or abnormal. When you open a jar of commercially or home-canned food, thoroughly inspect the product. Do not taste or eat foods that are discolored, moldy, or smell bad. Do not use products that spurt liquid or foam when the container is opened. Inspect your commercial and home-canned foods Don’t open or puncture any unopened cans, commercial or home-canned, if you suspect contamination. Suspect contamination if The container is leaking, bulging, or swollen The container looks damaged, cracked, or abnormal The container spurts liquid or foam when opened The food is discolored, moldy, or smells bad Safely dispose of food and cans that may be contaminated Put on rubber or latex gloves before handling open containers of food that you think may be contaminated. Avoid splashing the contaminated food on your skin. Place the food or can in a sealable bag. Wrap another plastic bag around the sealable bag. Tape the bags shut tightly. Place bags in a trash receptacle for non-recyclable trash outside the home and out of reach of humans and pets. Don’t discard the food in a sink, garbage disposal, or toilet. Wash your hands with soap and running water for at least 2 minutes after handling food or containers that may be contaminated. Wipe up spills using a bleach solution Add ¼ cup bleach for each 2 cups of water. Completely cover the spill with the bleach solution. Place a layer of paper towels, 5 to 10 towels thick, on top of the bleach. Let the towels sit for at least 15 minutes. Wipe up any remaining liquid with new paper towels. Clean the area with liquid soap and water to remove the bleach. Wash your hands with soap and running water for at least 2 minutes. Discard sponges, cloths, rags, paper towels, and gloves that may have come into contact with contaminated food or containers with the food. Online Resources General Information Botulism (Clostridium botulinum) General Information Podcast: What is Botulism? Botulism at Home-Canned Vegetables: Delicious and Safe Foodborne Illness Q&A Home Canning The Complete USDA Guide to Home Canning[PDF – 504KB] Blog: Home-Canned Vegetables: Delicious and Safe National Center for Home Food Preservation Preserving Food at Home: A Self-Study So Easy to Preserve Temperatures for Food Preservation Processing Times pH Values for Foods