Don’t invite botulism to your dinner table.

Botulism is a deadly form of food poisoning. It’s most commonly found in improperly processed home-canned vegetables, such as peas, peppers, corn, lima beans, green beans and mushrooms, as well as other low-acid foods canned at home, including soups, meats, fish and poultry. However, it also can be found in commercially canned foods.

If canned food isn’t processed properly, spores of the bacteria Clostridium botulinum aren’t killed.

Just a teaspoon of pure botulism poison could kill millions of people, according to the national Centers for Disease Control and Prevention. Even just a taste of contaminated food can make a person sick.

Symptoms include blurred or double vision, slurred speech, difficulty swallowing, muscle weakness, nausea, vomiting, stomachache and diarrhea. The symptoms usually start to appear 18 to 36 hours after eating food containing the toxin. Botulism is treatable if the victim receives prompt medical care. Without treatment, the illness causes paralysis that starts with the head and moves to the arms and legs and can cause death, the CDC says.

“We’re in the heart of home canning season, so it’s critical to use up-to-date equipment and research-tested methods,” says Julie Garden-Robinson, North Dakota State University Extension Service food and nutrition specialist. “I’ve noticed that many people are unaware that home-canned tomatoes need to be acidified with lemon juice or citric acid and properly processed to be safe.”

The proper equipment for safely canning low-acid foods such as vegetables and meat includes a pressure canner and standard canning jars with new two-piece lids.

Foods such as salsa, which is a mix of acid and low-acid ingredients, also need to be properly acidified with lemon juice or vinegar, using a tested formula, and processed according to current recommendations.

“If you have a favorite salsa recipe that hasn’t been research tested, it’s safest to freeze it rather than can it,” Garden-Robinson adds.

Food containing the botulism toxin generally doesn’t taste or look unusual, although the cans may provide a clue that the food is contaminated. Garden-Robinson recommends throwing away any cans that are swollen or bulging and food from glass jars with bulging lids. You shouldn’t taste food from swollen containers or food that is foamy or smells bad.

You also should get rid of recalled commercially canned products without opening the cans. For information on the brand names and UPC codes of recalled foods, visit the FDA Web site at http://www.fda.gov/default.htm.

To keep humans and animals away from the tainted food, the Food and Drug Administration advises double bagging it in plastic bags and disposing of it with nonrecylable trash.

For research-based information on home canning, visit the NDSU Extension Web site at http://www.ag.ndsu.nodak.edu/storage.htm.

But even properly processed canned foods won’t last forever. For example, cans and metal lids on glass jars can rust. The acid in foods such as tomatoes and fruit juices can cause cans to corrode. Light may cause food in glass jars to change color and lose nutrients. Temperatures above 100 F can cause food to spoil.

Here is some advice for storing canned foods:

• Store them in a cool, clean, dry place where temperatures are below 85 degrees. Temperatures in the 60- to 70-degree range are ideal.
• Store commercially canned low-acid foods, such as green beans and peas, in a cupboard for up to five years, but use them within a year for best quality.
• Use high-acid foods, such as tomato-based products, within 12 to 18 months. Foods stored longer will be safe to eat if they show no signs of spoilage and the cans don’t appear to be damaged, but the food’s color, flavor and nutritive value may have deteriorated.

NDSU Agriculture Communication