Alaskan Dilemma: Native Food Preparation Fosters Botulism

by Food and Drug Administration (FDA)

Cultural traditions die hard. Passed on from generation to generation, they are a source of pride and enjoyment, often serving to identify and bind the members of the group. But sometimes these customs can be dangerous, even deadly.

This is the case with the ways Alaskan Natives prepare certain traditional foods. Some of these methods of preparation foster botulism.

Alaskan Natives suffer the highest incidence of botulism in the world, says Jeffery Rhodehamel, research microbiologist with FDA's Center for Food Safety and Applied Nutrition.

Several government agencies, including the Food and Drug Administration, are working with Alaskan Natives to educate them about the dangers and lessen the threat of this disease.

"The reason for the high rate of botulism among Alaskan Natives," says Rhodehamel, "is that their traditional ethnic foods involve some risk. Most are home-processed fish or sea mammals — whale blubber [fat], seal flippers, or seal blubber — and the methods of preparation foster contamination and growth of Clostridium botulinum. These bacteria produce the deadly botulinal toxin that causes the disease.

"Botulism is not new to Alaska. In the early 1900s, explorers and whalers noted that whole families of Natives would be wiped out, with the deaths attributed to ptomaine poisoning. Others later suspected trichinosis to be the cause. It wasn't until the mid-20th century that the Canadian scientist Claude E. Dolman, in a 1960 article in the journal Arctic, postulated botulism as the probable cause, based on the food practices of certain Native populations. In the last 30 years, laboratory methods have confirmed many of the more recent outbreaks as botulism.

Nerve Symptoms

The disease affects nerve transmission, causing weakness and paralysis, and possibly death. Symptoms come on abruptly, usually from 18 to 36 hours after ingestion of the botulinal toxin, and may progress rapidly over several days.

The toxin binds to nerve endings and prevents release of the neurotransmitter acetylcholine, which transfers messages to the next nerve. With transmission of nerve impulses blocked, weakness and paralysis result.

"It tends to attack the cranial nerves first," says Rhodehamel, "followed by a descending, symmetrical paralysis. The eyelids droop, there is difficulty swallowing and dry mouth, vertigo, dizziness, lassitude. It moves down, and the limbs become paralyzed. Once the muscles of the chest and diaphragm are involved, respiration is inhibited. Respiratory failure and pneumonia are the greatest threat to life.

"Nausea, vomiting, abdominal cramps, and diarrhea may precede the neurological symptoms.

Treatment is with antitoxin developed from horse serum. The quicker antitoxin is administered, the sooner the progression of the disease can be halted. This is because the antitoxin destroys only the free circulating botulinal toxin; it has no effect on toxin already bound to nerve endings.

Recovery is a slow process because it generally takes months for nerves to regenerate. Weakness may persist for as long as a year after onset of the disease.

Growing Problem

Since 1966, the yearly incidence of botulism in Alaska has increased from 1.2 cases per 100,000 population to 15.2 cases per 100,000, according to a 1988 report in the Journal of Infectious Diseases. In fact, the problem has become so acute that the national Centers for Disease Control in Atlanta now stocks its Arctic Research Station with botulism antitoxin. Normally, the antitoxin has to be requested and distributed directly from the agency in Atlanta.

Several factors contribute to the high incidence of botulism among Native Alaskans:- Spores of Clostridium botulinum bacteria are ubiquitous in Alaska, especially in the western and southeastern beaches and coastal areas.

The spores have also been found in the gills of fish and in the entrails of fish and sea mammals, which make up a large portion of the Native Alaskan diet.

The traditional methods of preparing and storing these seafoods promote C. botulinum contamination and growth. The animals are often slaughtered on the beach or on ground where contact with bacteria from the soil or viscera is unavoidable. The food is then placed in a cool, shaded, shallow pit in the ground lined with wood, animal skins, or leaves. It is covered with moss or leaves and left to "ferment" for a month or two.

"Actually, it's not a true fermentation," explains Rhodehamel, "because there are no carbohydrates or sugars that are fermenting. Generally, in fermentation with carbohydrates, acid is produced, which would inhibit growth of the bacteria.

"The foods prepared this way, however, consist of fats and proteins, basically decomposing. Botulism outbreaks associated with fermented fish heads (called "stinkheads") and fish eggs ("stink eggs") occur in the summer, while outbreaks associated with fermented whale ("muktuk"), beaver tail ("stinky tail"), and seal flipper occur throughout the year, reports Nathan Shaffer, M.D., and colleagues in a recent article in the Western Journal of Medicine.

Despite the expectation that outbreaks would decrease with increasing education campaigns, the annual number of outbreaks has remained relatively constant since the 1970s, Shaffer reports, and recent outbreaks in Alaska have occurred in previously unaffected regions. (All outbreaks of botulism in Alaska reported since 1970 have been investigated by the state's Division of Public Health or CDC's Arctic Investigations Laboratory, and all hospitalized patients have been examined by a physician from one or the other agency.

Technology Complicates Situation

Ironically, modern technology has added to the problem rather than alleviated it because of the introduction of new implements. Native Americans are increasingly using plastic bags to line the pits and enclose the food, promoting the anaerobic conditions (absence of oxygen) necessary for growth of C. botulinum and subsequent production of the toxin responsible for the illness.

Plastic buckets and glass jars also complicate the problem. The food may be put in plastic buckets with the lids snapped tightly shut, providing an anaerobic environment, and then left to ferment above ground. The warmer, above-ground temperatures foster growth of the bacteria. Or the food is put in a glass jar and kept in the house next to the stove at about 30 degrees Celsius (86 degrees Fahrenheit), an almost optimum temperature for C. botulinum growth. Prepared this way, the food is ready in about a week, and has been dubbed traditional "fast food" by some government investigators.

A review of botulism outbreaks in Alaska from 1947 to 1985 published in the Journal of Infectious Diseases in June 1988 reported that all 59 confirmed or suspected outbreaks during that period occurred in Alaskan Natives and were associated with eating traditional Alaskan Native foods.

"The traditional methods of preparation might well have served originally to provide essential nutrients lacking in the diet," says Miriam Lancaster, a nurse with the Alaskan Native Health Service in Anchorage. "The fermentation process softens fish bones so they are edible," she explains, "providing a usable source of calcium, a nutrient that has not been readily available in the diets of Alaskan Natives. Also, fermenting foods may release vitamin B.

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