OREGON STATE UNIVERSITY

Botulism case calls attention to home food preservation

09/09/1997

CORVALLIS - The first thing you notice during the telephone conversation is that Susan speaks slowly and deliberately. Maybe she simply wants to choose just the right words. Or, you wonder, maybe she still has to struggle to pronounce them clearly.

Even though it is now August, perhaps Susan (not her real name) has not completely recovered from the botulism poisoning she contracted from eating home-canned beets in February 1997.

Susan, who is professionally employed, lives in southern Oregon. She and her mother ate the beets for lunch. Even though the beets had a strange taste, Susan assumed it was caused by an ongoing sinus infection. She remembers not feeling well the next day, but she went to work anyway.

By the end of the day, her vision began to blur, she couldn't touch the top of her mouth with her tongue, and she had difficulty breathing and keeping her balance. Her mother reported similar symptoms.

Botulism is caused by the Clostridium botulinum bacteria. Inactive spores of this bacteria are found in soil and water throughout the world. The soil in the western United States from the Rocky Mountains to the Pacific Ocean contains a particularly high count of Type A spores, the strain that produces the toxin most dangerous to humans.

In spore form, these bacteria are relatively harmless. The problem occurs when the spores germinate into growing cells. As the cells grow, they become overpopulated and begin to die, producing a deadly toxin that causes botulism.

Several conditions must be present for the spores to germinate and grow, according to Carolyn Raab, Oregon State University Extension foods and nutrition specialist.

The spores can grow in foods with a lower acid level when oxygen, or air, is not present in the area immediately next to them. "It's possible to have conditions develop in situations that, to the naked eye, do not appear dangerous," Raab said.

Because oxygen-free conditions develop when food is canned, botulism has most commonly been associated with canned foods. Home canning recipes for low acid foods, such as vegetables, call for use of a pressure canner to attain temperatures high enough to kill any botulinum spores that may be present.

The home-canned beets that poisoned Susan and her mother had been canned in a boiling water canner rather than a pressure canner. "I learned about botulism as a kid and I knew that certain vegetables had to be processed at higher temperatures than you get with a hot water bath.

"But I thought that applied only to green beans and tomatoes," Susan said.

While green beans do have to be pressure-canned, tomatoes are more acidic and may be safely processed in a boiling water canner following laboratory-tested instructions.

Although she didn't think it was pertinent, Susan raised the possibility of botulism with her doctor and told him about the beets. In the meantime, the symptoms worsened. Her mother was hospitalized immediately. Three days after eating the beets, Susan went to the hospital. She was experiencing blurred vision, slurred speech, had difficulty walking and had no gag reflex.

A paralytic illness, botulism can be mistakenly diagnosed as Guillain-Barre syndrome, stroke, myasthenia gravis and tick paralysis, among others. Treatment includes administration of an antitoxin. Six days after eating the tainted beets, Susan was flown to the Oregon Health Sciences Center in Portland where she was given antitoxin.

By then she was on a ventilator to assist her in breathing. Her paralysis spread, allowing movement only in her hands and lower legs. She could communicate only by writing messages. Her mother, completely paralyzed and unable to go to Portland, received the antitoxin in southern Oregon.

Susan did not recover quickly. After being removed from a respirator, she experienced another respiratory failure and had a tracheotomy. In mid-March she was moved to the hospital near her home.

After treatment in a transitional center where she learned to use a walker, Susan returned home in early April. Her mother remained in the local hospital and died later that month. It wasn't until July, five months after the onset of botulism, that Susan had almost fully recovered.

The beets had been a gift from a friend's garden, Susan explained. She had canned them in a boiling water canner, following the directions in a commercial canning book that was 25 years old. It was also the way she and her family had always canned beets. This time, however, they ate them raw rather than boiling them first. Boiling would have destroyed the toxin that causes botulism.

Susan's case is far from unique, according to Raab. The U.S. Department of Agriculture made major changes in home-canning recommendations in 1988; anything published before that date should be considered outdated, she pointed out.

"A lot of pre-1988 canning books are still on kitchen and library shelves where they will continue to pose a threat to health," Raab said.

People who are unsure whether home-canned vegetables are safe to eat should boil them for 10 minutes plus one minute for every 1,000 feet above sea level.

For up-to-date instructions on canning foods safely, contact your local county Extension office. An OSU Extension Service Food Preservation Hotline will be operating from 9 a.m. to 4 p.m., Monday through Friday, until Sept. 30 to answer questions. The hotline number is 1-800-345-7319.

As for Susan, one way in which she has begun putting her life back together has been to share her ordeal with others. She hopes her example others from a similar fate.