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Botulism

A toxin produced in food by the micro-organism Clostridium botulinum causes botulism. It is found in soil all over the world. The organism has the ability to form a spore very resistant to heat and chemicals. Its toxin is the most deadly we know.

Cases are rare, but each year several outbreaks of individual cases occur.

Foods Commonly Involved

Home-canned or commercially canned or processed low-acid vegetables, meats, fish, and poultry that have been insufficiently heated during processing or canning are the foods commonly involved. They include peas, corn, lima beans, green beans, mushrooms, sauces, and soups.

Conditions Needed For Botulism Outbreak

Several conditions are necessary:
  1. The botulinum organism must be in the food.
  2. The food is canned or processed in some way.
  3. Inadequate processing or heating lets spores live and toxins form.
  4. Conditions after processing let spores grow and toxins form.
  5. The food is not heated enough before eating to kill the toxin.
  6. Someone eats the poisonous food.

Prevention Alert

Discard all raw or canned food that shows any sign of being spoiled.

Discard all bulging or swollen cans of food and food from glass jars with bulging lids.

Do not taste food from swollen containers or food that is foamy or has a bad odor.

Process low-acid foods at temperatures above boiling and for the recommended time for the size of can or jar you are using.

Can low-acid foods in a pressure canner. Do not can low-acid foods in the oven, in water-bath, open kettle, or vegetable cooker.

Heat home-canned low-acid foods to a rolling boil, then cover and boil corn, spinach and meats for 20 minutes and all other home-canned low-acid foods for 10 minutes before tasting.

When In Doubt, Throw It Out

Botulism Symptoms

Symptoms include difficulty in swallowing, speech, and respiration; double vision. The person affected will die from paralysis of respiratory muscles unless the correct antitoxin is administered promptly.

Temperature of Foods for Control of Bacteria

  • 0 °F - 32 °F -- Freezing temperatures stop growth of bacteria but may allow bacteria to survive. (Do not store food above 10 °F for more than a few weeks.)
  • 32 °F - 40 °F -- Cold temperatures permit slow growth of some bacteria that cause spoilage.*
  • 40 °F - 60 °F -- Some growth of food poisoning bacteria may occur.
  • 60 °F - 125 °F -- DANGER ZONE. Temperatures in this zone allow rapid growth of bacteria and production of toxins by some bacteria. (Do not hold foods in this temperature zone for more than 2 or 3 hours.)
  • 125 °F - 140 °F -- Some bacterial growth may occur. Many bacteria survive.
  • 140 °F - 165 °F -- Warming temperatures prevent growth but allow survival of some bacteria.
  • 165 °F - 212 °F -- Cooking temperatures destroy most bacteria. Time required to kill bacteria decreases as temperature is increased.
  • 212 °F - 240 °F -- Canning temperatures for fruits, tomatoes, and pickles in waterbath canner.
  • 240 °F - 250 °F -- Canning temperatures for low-acid vegetables, meat, and poultry in pressure canner.
* Do not store raw meats for more than 5 days or poultry, fish or ground meat for more than 2 days in refrigerator.

Botulism (Bacterial Foodborne Illness): Causes, Symptoms, and Control

What Causes It

Clostridium botulinum. Spore-forming organisms that grow and produce toxin in the absence of oxygen, such as in a sealed container.

Spores are extremely heat resistant. Spores are harmless, but the toxin is a deadly poison.

Symptoms

Double vision, inability to swallow, speech difficulty, progressive respiratory paralysis. Fatality rate is high, in the United States about 65 percent.

Characteristics of Illness

Transmitted by eating food containing the toxin.

Onset: Usually within 12 to 36 hours or longer.

Duration: 3 to 6 days.

Control Measures

Bacterial spores in food are destroyed by high temperatures obtained only in the pressure canner. More than 6 hours is needed to kill the spores at boiling temperature (212 °F).

The toxin is destroyed by boiling for 10 to 20 minutes; time required depends on kind of food.

By Melissa Mixon, Ph.D., R.D., L.D., Extension Leader -- Home Economics, and Human Nutrition Specialist

Mississippi State University does not discriminate on the basis of race, color, religion, national origin, sex, age, disability, or veteran status.

Information Sheet 734
Extension Service of Mississippi State University, cooperating with U.S. Department of Agriculture. Published in furtherance of Acts of Congress, May 8 and June 30, 1914. Ronald A. Brown, Director

Copyright by Mississippi State University. All rights reserved.

This document may be copied and distributed for nonprofit educational purposes provided that credit is given to the Mississippi State University Extension Service.

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