You wouldn't think that a can of "hot dog chili sauce" would be particularly dangerous. Unappetizing, maybe, but not dangerous. Yet in the summer of 2007, at least eight people in Texas, Indiana, and Ohio became extremely ill after eating sauce made by Castleberry's Food Company. Tests showed that the condiment contained botulinum toxin, a nerve poison produced by the bacterium Clostridium botulinum. Those eight people had contracted botulism, a rare but serious illness that continues to show up in unexpected places.
The botulism bug is a close cousin of the germ that causes tetanus, Clostridium tetani. Like tetanus, it is common in the soil, makes spores that allow it to survive until better conditions arrive, is anaerobic (does not need oxygen to grow) and produces a dangerous neurotoxin.
Botulinum toxin -- the key ingredient in Botox injections -- is also prized by plastic surgeons and cosmetic dermatologists because it temporarily paralyzes certain facial muscles, which reduces wrinkles. Those same powers make the toxin very dangerous when it shows up in food. In fact, botulinum toxin is one of the most poisonous compounds in nature. If you get some in your bloodstream or digestive system -- as opposed to a site carefully chosen by a doctor -- just a few billionths of a gram can be enough to make you sick.
How do people catch botulism?
Infant botulism is the most common form of the disease in the United States, with about 80 cases reported each year. It usually occurs between the ages of 6 weeks and 6 months. Babies have immature digestive systems, and botulism spores from their food or air can sometimes lead to infections. Honey often has botulism spores in it and is the leading known cause of infant botulism, though in 85 percent of infant botulism cases the babies did not eat honey and the cause is unknown.
People develop botulism in two basic ways: from contaminated food and, much more rarely, from infected wounds. Neither scenario is very common in this country. According to the CDC, there are fewer than 30 reported cases of food-borne botulism in the United States each year and only two or three cases of wound botulism. A few scattered cases of wound botulism have occurred in people injecting illegal drugs and people who received unlicensed botulism toxin injections.
The botulism germ can hide in many different foods. Home-canned foods -- especially low-acid vegetables such as beets, corn, and beans -- are a leading cause of botulism in the United States. But, as the chili sauce episode shows, commercial products can be contaminated, too. People have developed botulism from canned soups, meats, sausages, canned seafood, and canned vegetables.
What are the symptoms of botulism?
While symptoms of food-borne botulism generally start within 12 to 36 hours, it can take 10 days to notice signs of wound botulism.
As the toxin starts to attack nerves and muscles, patients have extreme trouble swallowing or breathing. Lack of oxygen is the main cause of botulism-related death. Other symptoms include weakness in facial muscles, double vision, nausea, and vomiting. In severe cases the victim can be temporarily paralyzed.
Constipation is often the first sign of infant botulism. (But don't forget that constipation in babies and adults is in most cases due to some other cause.) After that, babies can lose muscle control, leaving them floppy and unable to lift their heads. Other signs include weak crying, droopy eyelids, excessive sleepiness, and trouble sucking or feeding. If you see these signs in a baby, you should call your doctor right away.
To prevent infant botulism, do not give honey or corn syrup to children under age one. Honey is safe for older children.
Not long ago, botulism killed about half of all of its victims. Thanks to better treatments, the death rate has fallen to less than 10 percent. The earlier botulism is diagnosed, the more likely it is that treatment can prevent the botulism toxin from causing more severe illness.
What is the treatment for botulism?
The toxin affects the nerves and their ability to communicate with muscles, so patients need help with anything requiring muscle movement. More than anything else, botulism patients need help breathing. They may need to be hospitalized and hooked up to a ventilator for weeks.
For food-borne and wound botulism, doctors may prescribe an antitoxin, which blocks the action of the toxic bacteria circulating in the blood. This can prevent the illness from getting worse and also reduce the chances of complications. Even with the best treatment, recovery is a long process. Tiredness and shortness of breath can last for years.
Treating infant botulism usually requires a stay in the intensive care unit, where doctors can monitor the child's airway, give tube feedings, and provide occupational and physical therapy. The doctor will also prescribe medicine called botulinum immune globulin, which can reduce the need for mechanical ventilation and feeding tubes and also shorten the amount of time spent in the hospital.
How can I avoid botulism?
Even though botulism is extremely rare, it's still a good idea to be careful with your food. Cooking food will inactivate the toxin. If you're preparing fermented or preserved foods yourself, be sure to pressure cook everything at 250 degrees F for at least a half hour. You should also consider boiling these foods for 10 minutes before serving them. Alaska has the highest rate of food-borne botulism cases because certain Native Alaskan foods are now preserved or fermented in airtight containers.
Never buy or use any food in a bulging, dented, or broken can. Also toss anything that spurts out or looks foamy when you open the jar or can. Always discard anything that looks rotten or smells spoiled, even though food infected with botulinum toxin has no telltale smell, and "off"-smelling food may not necessarily be poisonous.
Oils infused with garlic or herbs are another possible source of botulism. Commercially made products should be safe, but if you make your own or buy any at the farmers' market, keep the oil refrigerated and use it within a few days. If you plan to store your oil longer, heat the oil when infusing and keep it in the refrigerator no more than a month.
Centers for Disease Control and Prevention. Botulism. October 2010.
Louisiana Department of Health and Hospitals. Infectious Disease Epidemiology Section, Office of Public Health. Clostridium. December 21, 2006.
Centers for Disease Control and Prevention. Botulism associated with canned chili sauce, July-August 2007.
U.S. Food and Drug Administration. Bad bug book: Clostridium botulinum. 1992 (with updates)
Nadine Cox, MD, and Randy Hinkle, DO. Infant Botulism. American Family Physician. April 1, 2002.
Mayo Clinic. Botulism. March 27, 2010.
United States Department of Agriculture. Frozen, fully cooked products and botulism --Food safety advisory. 2001.
Clemson extension service. Botulism. 2007.
CDC. Wound botulism among black tar heroin users -- Washington, 2003. MMWR. September 19, 2003.
Chertow, D.S., Tan, E.T., et al. Botulism in 4 adults following cosmetic injections with an unlicensed, highly concentrated botulinum preparation. JAMA. Vol. 296, No. 20. November 22/29, 2006.
CDC. Botulism Outbreak Associated With Eating Fermented Food -- Alaska, 2001. MMWR. August 17, 2001
California Poison Control System. Food poisoning and safety.
Pennsylvania Department of Health. Communicable disease fact sheets: Botulism fact sheet.
Food Safety Information Society (Canada). Flavoured oils.