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Foodborne Botulism -- Oklahoma, 1994

On July 2, 1994, the Arkansas Department of Health and the Oklahoma State Department of Health were notified about a possible case of foodborne botulism. This report summarizes the investigation, which implicated consumption of improperly stored beef stew.

On June 30, 1994, a 47-year-old resident of Oklahoma was admitted to an Arkansas hospital with subacute onset of progressive dizziness, blurred vision, slurred speech, difficulty swallowing, and nausea. Findings on examination included ptosis, extraocular palsies, facial paralysis, palatal weakness, and impaired gag reflex. The patient also had partially healed superficial knee wounds incurred while laying cement. He developed respiratory compromise and required mechanical ventilation.

Differential diagnoses included wound and foodborne botulism, and botulism antitoxin was administered intravenously. Electromyography demonstrated an incremental response to rapid repetitive stimulation consistent with botulism. Anaerobic culture of the wounds were negative for Clostridium. However, analysis of a stool sample obtained on July 5 detected type A toxin, and culture of stool yielded C. botulinum. The patient was hospitalized for 49 days, including 42 days on mechanical ventilation, before being discharged.

The patient had reported that, during the 24 hours before onset of symptoms, he had eaten home-canned green beans and a stew containing roast beef and potatoes. Although analysis of the leftover green beans was negative for botulism toxin, type A toxin was detected in the stew. The stew had been cooked, covered with a heavy lid, and left on the stove for 3 days before being eaten without reheating. No other persons had eaten the stew. Reported by: W Knubley, MD, Cooper Clinic, Fort Smith; TC McChesney, DVM, State Epidemiologist, Arkansas Dept of Health. J Mallonee, MPH, Acting State Epidemiologist, Oklahoma State Dept of Health. Foodborne and Diarrheal Diseases Br, Div of Bacterial and Mycotic Diseases, National Center for Infectious Diseases; Div of Field Epidemiology, Epidemiology Program Office, CDC.

Editorial Note

Editorial Note: Botulism is a paralytic illness resulting from a potent toxin produced under anaerobic conditions by C. botulinum. Although foodborne botulism is rare in the United States (34 cases reported in 1994 {CDC, unpublished data, 1995}), manifestations can be severe and can progress rapidly. Because of the potential severity of disease and the possibility for exposure of many persons to contaminated products, foodborne botulism is a public health emergency requiring rapid investigation.

When botulism is suggested by clinical manifestations, (e.g., descending neuroparalysis, ptosis, and extraocular palsies), physicians should obtain a thorough food history to assist in the diagnosis and in identifying and obtaining potentially contaminated leftover food. In the case described in this report, heat-resistant C. botulinum spores either survived the initial cooking or were introduced afterwards; the spores subsequently germinated and produced toxin. The lid of the pot or the gravy of the stew most likely provided the anaerobic environment necessary for toxin production. Previous cases with similar features have resulted from consumption of commercial pot pies (1) and onions sauteed in margarine (2), both of which were left at room temperature for greater than 4 hours after cooking.

Most outbreaks of foodborne botulism in the United States result from eating improperly preserved home-canned foods (3); vegetables (especially asparagus, green beans, and peppers) account for most outbreaks caused by home-canning (CDC, unpublished data, 1995). A pressure cooker must be used to home-can vegetables safely because it can reach temperatures necessary to kill botulism spores (substantially greater than 212 F { greater than 100 C} for 10 minutes); however, specific times and pressures needed vary for different foods (4). Jams and jellies can be safely home-canned without a pressure cooker because their high sugar content will not support the growth of C. botulinum. Instructions for home-canning are available from county extension offices. Cooked foods should not be held at temperatures 40 F-140 F (4 C-60 C) for greater than 4 hours (5). Boiling food for 10 minutes before eating destroys any toxin present.

CDC provides epidemiologic consultation and laboratory diagnostic services for suspected botulism cases and authorizes release of botulism antitoxin to state health departments and physicians in the United States. These services are available 24 hours a day from CDC through state health departments.


  1. CDC. Botulism and commercial pot pie -- California. MMWR 1983;32:39-40,45.

  2. MacDonald KL, Spengler RF, Hatheway CL, Hargrett NT, Cohen ML. Type A botulism from sauteed onions: clinical and epidemiologic observations. JAMA 1985;253:1275-8.

  3. St. Louis ME. Botulism. In: Evans AS, Brachman P, eds. Bacterial infections of humans: epidemiology and control. 2nd ed. New York: Plenum Publishing, 1991:115-31.

  4. Extension Service, US Department of Agriculture. Complete guide to home canning. Washington, DC: US Department of Agriculture, Extension Service, September 1994. (Agriculture information bulletin no. 539).

  5. Food and Drug Administration. Food code, 1993. Washington, DC: US Department of Health and Human Services, Public Health Service, Food and Drug Administration, 1993.

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