A little hesitant about accepting that jar of home-pickled beets from Aunt Martha this year because last year's batch left you feeling a little queasy? It could be that Aunt Martha's canning techniques need some upgrading. She could be exposing everyone on her pickled beet list to the bacterium that causes botulism.

What is botulism?

It's an illness caused by Clostridium botulinum (C. botulinum). The bacterium itself does not make people sick, but the toxins it produces do.

There are three main types of botulism:

• Food-borne botulism is caused by eating foods that contain the botulism toxin.
• Infant botulism is caused when infants consume spores of the botulinum bacteria, which then grow in the intestines and release toxins.
• Wound botulism occurs when the bacterium comes in contact with an open wound.

All cases of botulism are considered medical emergencies and can be fatal. Food-borne botulism is especially worrisome because it can mean that large numbers of people can be exposed if commercially manufactured food contains C. botulinum.

The bacterium is commonly found in soils throughout the world. It flourishes in conditions of low acidity, low oxygen and high water content.

What are the symptoms?

Symptoms of botulism include nausea, vomiting, fatigue, dizziness, headache, double vision, drooping eyelids, slurred speech, dryness in the throat and nose, and respiratory failure. Infants with botulism appear lethargic, are fussy eaters and constipated, and cry weakly.

The toxins created by the bacterium that causes botulism affect muscles and can lead to paralysis of the legs, arms, trunk and respiratory muscles. In food-borne botulism, symptoms generally begin 18 to 36 hours after eating contaminated food. But it can take as long as 10 days for symptoms to appear.

You could be sick for two to 10 days. If you've been severely affected, it could take months to recover. You could even experience fatigue and shortness of breath for several years and need long-term therapy.

The toxins created by the bacterium that causes botulism are extremely potent and can kill even in very small doses. It is estimated to be up to 100,000 times more toxic than sarin, the nerve agent used in the attack in Tokyo's subway system in 1995.

The death rate from respiratory failure caused by botulism has fallen from 50 per cent to about eight per cent over the past 50 years.

How can I tell if my food is contaminated with botulism?

Not by looking at it or smelling it. You won't taste anything odd, either. You usually don't know that your food is contaminated until you start showing symptoms.

How common is botulism?

Not very. There are usually fewer than 20 cases in Canada a year. Most cases tend to be infant botulism. The gastrointestinal tracts of infants are less developed than those of adults, which tends to leave infants more susceptible to the bacterium than adults. Infants are especially at risk if they consume honey, which can carry C. botulinum. While the bacteria cannot grow or produce toxins in honey, it can in a baby's digestive system.

Most other cases of botulism in Canada result from improper home canning methods, especially involving low-acid foods such as asparagus, corn, green beans, mushrooms and beets — and some fish or meats. In some cases, chili peppers, tomatoes and garlic stored improperly in oil have led to cases of botulism.

It is rare for botulism to be spread through commercially produced foods, although recent food scares have prompted extensive recalls. In October 2006, two Toronto residents were hospitalized after drinking tainted carrot juice. In July 2007, cans of chili, stews and chili sauce were pulled from store shelves in North America because of contamination fears.

How is botulism treated?

Botulism must be diagnosed and treated quickly with an antitoxin. That won't reverse the effects of the disease, but it can prevent further paralysis. Antibiotics don't do much -unless you are suffering from secondary infections. Other than that, about all that can be done for you is supportive care as needed, including mechanical ventilation if you have trouble breathing.

How do I avoid getting botulism?

In the vast majority of cases, Canada's food safety regulations do that job for you. But if you're going to can foods at home, make sure you closely adhere to safe canning guidelines, which include:

• Use a pressure canner to eliminate air in the container.
• Clean and sanitize your hands, all work surfaces, food, utensils and equipment and keep them clean during all stages of the canning process.
• Use containers specifically designed for home canning. Do not use coffee, salad dressing or other jars.

Never eat canned or bottled foods if you suspect the item has been tampered with, if the closure/seal has been broken, or if the container is leaking or bulging. Refrigerate oils infused with garlic or herbs.

Consider boiling your canned food for 10 minutes before you eat it. The high temperatures will kill any bacterium waiting to do its work in your digestive system.

Never feed honey to children under a year old. Bees may pick up the botulism spores from flowers or soil and the spores are not destroyed in the processing of honey.

If you suspect an object or surface has been contaminated with botulism and the object or surface cannot be avoided for the hours to days required for natural degradation, clean it with a 0.1% hypochlorite bleach solution.

Botulism is not contagious, so you won't get it from coming in contact with an infected person. But it is possible that botulism could be spread through a chemical weapon. You could inhale the bacterium and get sick.

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