How You Can Keep At-Home Canning Safe and Avoid Botulism

By: Laura Jeffers, MEd, RD, LD

Canning your own fruits and vegetables at home has many benefits, but it also brings an increased risk for food-borne illness. While a rare occurrence, botulism is usually is associated with home canning. It is dangerous and can even be deadly.

Types of botulism

Botulism is a serious illness that paralyzes muscles and can even lead to death. It’s caused by a nerve toxin from the bacterium Clostridium botulinum, which also has medical uses.

There are three main forms of botulism infection that occur naturally: infant botulism, wound botulism and food-borne botulism.

1. Infant botulism is the most common form, affecting children younger than age 1. An intestinal infection of botulinum spores causes infant botulism, and it mainly affects the nervous system. These spores are common and can be found in many foods, such as honey. To be safe, don’t feed infants honey until after their first birthday. Also, make sure any milk, juices or food products have been pasteurized or thoroughly cooked.
2. Food-borne botulism can affect anyone, and generally springs from improper home-canning procedures.
3. Wound botulism is rare and occurs when botulinum toxin infects an existing wound.

How you get it

Botulism doesn’t spread from person-to-person like the common cold. You can only contract food-borne botulism by eating a contaminated food. Foods that carry the botulinum toxin have usually been home-canned, home-bottled or poorly preserved.

Home-canned foods with low acid content, such as asparagus, green beans, beets and corn, can easily become infected if you don’t follow proper canning methods.

Other foods can be risky even if they’re handled by large manufacturers. Unusual problems involving chopped garlic in oil, canned cheese sauces, chili peppers, tomatoes, carrot juice and baked potatoes wrapped in foil have all been cited in documented botulism cases.

Avoiding botulism

The only way to avoid botulism is to avoid eating contaminated food. If you can or bottle your own foods, be sure to follow strict hygienic procedures. Use a pressure canner or cooker to thoroughly cook – or pasteurize – your food. The U.S. Department of Agriculture offers detailed, correct technique guidance.

Refrigerate any foods that use oils infused with garlic or herbs. Keep potatoes baked in foil hot until they’re served or refrigerate them. Otherwise, the lack of oxygen inside the foil can allow bacteria to multiply and produce more toxin.

To kill C botulinum spores, set your pressure cooker to 116°C. You need to cook foods until their internal temperature is 85°C for 10 minutes.

For homemade canned foods, consider boiling the food for 10 minutes before you eat it. It’s an extra step to ensure the food is toxin-free.

If a can or bottle has a bulging lid, don’t eat the food inside. Throw it away or return it, unopened, to the store where you bought it. And, never eat any food that doesn’t smell the way it should.

Signs to watch for

According to the Centers for Disease Control and Prevention, food-borne botulism symptoms generally show up between 12 and 36 hours after you eat a food carrying the toxin. Sometimes the signs can show up as quickly as six hours or as late as 10 days. The more quickly the symptoms appear, the more severe the case will be.

The main signs of food-borne botulism include:

• Difficulty swallowing or speaking
• Dry mouth
• Facial weakness (throughout the face)
• Blurred or double vision
• Drooping eyelids
• Difficulty breathing
• Nausea, vomiting and abdominal cramps
• Paralysis

In infants, symptoms also include constipation, poor feeding, excessive sleepiness, breathing problems and poor reflexes.

Treatment requires hospitalization

In some cases, doctors will induce vomiting or use enemas to cleanse your intestinal tract of any remaining botulism-laced food.

If you’re affected, you’ll likely need hospital care, including antitoxins, to prevent or help you recover from respiratory failure and paralysis.

Doctors put patients with severe cases on a ventilator and prescribe intensive medical and nursing care during recovery.

Outbreaks are rare

Widespread occurrences of botulism are rare. Though uncommon, outbreaks can be a public safety concern because many people can be infected by the same contaminated foods.