How to check frozen foods for botulism

In August and September, several cases of botulism, a life-threatening illness caused by the bacterium Clostridium botulinum, were reported in Texas.

Mishandled commercially frozen, fully cooked chili is suspected in these instances.

Botulism is most often linked to improperly canned, low-acid foods such as green beans and fish, so finding it in a frozen product is unusual.

The federal Food Safety and Inspection Service offers the following information on safe handling of frozen, fully cooked products.

In the store

• Before buying frozen, fully cooked products, carefully inspect the container or package. If the package is punctured, torn, partially opened or damaged in any other way that might expose the contents, do not purchase it.

• Do not purchase frozen products that appear to have been thawed and refrozen.

• Reject all swollen or gassy containers.

• Buy frozen products only if they are frozen solid and only if stored in the freezer case.

• Observe any use-by or sell-by dates.

At home

• When you open any food container, inspect the product. Do not use products that are discolored, moldy or have a bad odor.

• Do not use products that spurt liquid or foam when the container is opened.

• Do not taste the product to determine if it is safe.

• Follow preparation instructions on the label.

• Report any suspect commercial-food products to your local health department. Or call the U.S. Department of Agriculture's Meat and Poultry Hotline (800-535-4555; TDD/TTY 800-256-7072).

• If a suspect food is opened in your kitchen, thoroughly scrub the can opener and other utensils, containers, counters, floor, etc., that might have come in contact with the food or its container. Discard any sponges or cloths used in the cleanup. Wash your hands thoroughly and promptly launder any clothing that's been splattered.

How botulism develops

Botulism is a rare but serious paralytic illness caused by a nerve toxin. Symptoms of botulism include double vision, blurred vision, drooping eyelids, slurred speech, difficulty swallowing, dry mouth and muscle weakness. The illness can cause paralysis, respiratory failure and death.

Symptoms usually occur from 18 to 36 hours after eating contaminated food. Anyone who thinks they may have botulism should seek medical attention.

The spores of Clostridium botulinum can be found anywhere, including soil. So naturally, they can end up on foods that grow in soil. But under certain conditions they produce a deadly toxin, botulism. Their surroundings must be anaerobic, low-acid and warm. Anaerobic means it grows without air.

That is why botulism has been linked to a baked potato left in foil at room temperature for a prolonged period (more than a day), as well as unrefrigerated garlic in oil. The foil seals out air, allowing bacteria that cause botulism to grow and produce toxins.

If you add herbs or garlic to vegetable oil, it must be refrigerated and kept for no more than three weeks.