February 27, 2009 in City

Botulism blamed on improper home-canning

By The Spokesman-Review
 

A serious case of botulism in Spokane has prompted warnings from food preservation experts and health officials to follow strict safety rules when canning vegetables at home.

A nurse in her 30s, along with two children younger than 10, were stricken with the nerve toxin after eating improperly canned green beans from a backyard garden. All three were given an antitoxin that was flown to Spokane from a special storage facility in Seattle.

The woman, who has requested that her name be kept private, became gravely ill and remains on a ventilator and is recovering slowly. The children, who suffered milder symptoms, are also expected to recover.

While botulism cases are rare, they can be deadly.

The toxins emitted by botulism bacteria are considered paralytic. The toxins descend from the head, often striking a person’s sight first, blurring vision before making swallowing more difficult. When the effects of the toxins reach the respiratory system, breathing becomes labored and a person can die.

Dorothy MacEachern, an epidemiologist with the Spokane Regional Health District, said the rest of the suspect green beans have been collected and destroyed since the January 22 incident.

While this is not the canning season, it is the time of year when many families reach into the pantry to open jars of fruits and vegetables canned after last fall’s harvest.

MacEachern is concerned that people have been responding to difficult economic times by canning more of their food – perhaps improperly.

There are about 145 cases of botulism each year in the United States, according the Centers for Disease Control, only 15 percent of which come from food poisoning. Another 20 percent are what MacEachern called wound botulism, which is most prevalent among heroin addicts, and the remaining 65 percent of cases are infant botulism, caused when spores of the bacteria grow in a baby’s not-yet fully developed intestinal tract and release toxins.

The bacteria responsible for creating the botulism toxin, called clostridium botulinum, occur naturally in the soil and are not dangerous. The Northwest reportedly has higher levels of the bacteria than other areas of the country.

The bacteria produce toxins as a defense mechanism when placed in anaerobic, or oxygen-free, conditions such as sealed can or jar.

It’s why home food preservation can be risky.

“People always want to know if they can look at a jar of food to know if it’s okay,” said Lizann Powers-Hammond, a food safety and preservation expert with Washington State University Extension. “But I can’t tell by looking. What I need to know is the food’s history. How it was canned.”

Special precautions must be taken when canning low-acid foods such as green beans and asparagus. Since most vegetables don’t have enough natural acidity to kill the bacteria, they must be canned using a pressure canner that can reach high temperatures. Or, vegetables may be pickled with enough vinegar to inhibit growth of the bacteria.

As a safety precaution, canned vegetables should be boiled for 11 minutes at Spokane’s elevation before eating.

Foods that were not canned following U.S. Department of Agriculture standards should be thrown away before opening.


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