Botulism Case Highlights Need to Follow Canning Directions - North Carolina Health News
An Ashe County woman learned the hard way her food-preservation techniques were wrong.
By Rose Hoban
It only took one bite.
Five days later, an Ashe County woman lay in the hospital, on a ventilator, unable to breathe.
The woman, who’s name has not been released, told health officials she didn’t even swallow the carrot. She opened the home-canned jar of carrots, tasted one, decided it looked and tasted off, and spit it out.
But that was enough to give her botulism, sending her to the hospital for an 11-week stay.
She was lucky there was an off flavor, said Ben Chapman, a food-safety expert from N.C. State University.
“The toxin itself doesn’t have the sensory attributes that we associate with spoilage,” Chapman said this week at a presentation about the case during a meeting of the Governor’s Task Force on Food Safety and Defense that was held at the N.C. Biotechnology Center in Research Triangle Park.
Chapman said the procedure the woman had used to treat the carrots may have left some other bacteria behind that created the off taste. But her canning technique was not correct, which also left behind botulism spores in her carrots.
She was fortunate to have ingested a small enough amount that her hospital stay was relatively short compared to what happens in many botulism cases, Chapman said.
And he offered the story as a cautionary tale as we head into the main growing season when many people pull out pots and jars to preserve the fruits of the season.
Rare, but deadly
Clostridium botulinum is a kind of bacteria found widely in soil, along with the spores the bacteria uses to reproduce. The spores can survive in many kinds of soil and can cling to fruits and vegetables.
Those spores are hard to kill. It takes a lot of heat, about 240 degrees F, or a lot of acid like that found in a person’s stomach to inactivate a C. botulinum spore.
The spores thrive when they’re in an oxygen-deprived environment, such as that created when people can food. Under those conditions, the spores create a toxin.
The toxin is so potent that it only requires an amount equal to about a quarter of a grain of sand to kill someone. It kills by causing total muscle paralysis, including paralyzing the muscles that control breathing.
According to the Centers for Disease Control and Prevention, only about 145 cases of botulism are reported annually. Of those, about 15 percent are caused by home-canned food.
Currently, there’s an outbreak of botulism affecting about 40 people in Ohio who ate poorly canned potatoes at a church supper. One person has died, about 20 others are sick and the rest are being monitored by local health officials.
Once they realized they had a case of botulism poisoning on their hands, county, state and federal health officials acted to avoid an outbreak.
It took several days for a possible diagnosis of botulism poisoning to show up in the woman’s medical record, said Nicole Lee, an epidemiologist from the state Department of Health and Human Services. The woman’s daughters and a friend told doctors that she canned her own food. Before she was intubated, the woman said she suspected the carrots.
But doctors also needed to rule out a stroke or other neurological problems. It took more than a week for doctors to tell state health officials that they suspected botulism.
“That immediately got our attention,” said Lee. “We had gotten wind that this person was canning her own food. We weren’t sure if these items were being sold in commerce or across state lines.”
Lee also called the CDC to let them know there was a suspected case of botulism. That same day, the CDC released botulism antitoxin for the woman that was flown to Ashe County from Atlanta.
The cost for that anti-toxin: $80,000 for one dose.
Tracing the toxin
“I was on my way to Morganton and I got a call to divert,” recounted Susan Parrish, a food regulatory supervisor for the state Department of Agriculture and Consumer Services.
Parrish, who monitors food outbreaks around the state, was given the carrots by one of the woman’s friends.
“They were in a quart jar,” said Parrish, who put on a biohazard suit to handle it. “Obviously, she had only tasted a bite, because the jar was full.”
A sample of the carrots was shipped to the Food and Drug Administration.
The doctors at the hospital had sent a sample of the woman’s blood to the CDC for testing, and the results came back negative.
“To find things negative for toxin wouldn’t be unexpected,” said Lee. She explained that the botulism toxin binds securely to neuromuscular junctions preventing the body’s usual communication between nerves and muscles.
“What you’re testing for is toxin circulating in the system,” Lee said. “If those toxins are reaching those targets, when you test for the toxin there’s actually not that much left that’s circulating.”
The results came back from the FDA “barely positive,” said the FDA’s Mancia Walker. “But with [botulism], barely positive is like a little bit pregnant.”
The woman eventually tested positive for botulism in her stool, confirming the diagnosis.
In recent years, home canning has become more and more popular. According to the Jarden Corporation, which makes Ball canning jars, sales have exploded.
“No longer a niche homesteading practice, home canning is a mainstream culinary trend as food lovers nationwide seek to preserve the best local produce,” reads a 2014 press release from the company.
And that worries Ben Chapman, who said that all those new home canners are a generation or two away from people who canned out of necessity, rather than for fun, fashion or gift-giving.
“This was a tragic mistake that can happen to anyone not using proper canning procedures,” he said, explaining that the woman had not pressure canned the carrots, which would have created temperatures high enough to kill botulism spores.
“By boiling the water bath, there is this 200 degree kill of vegetative cells,” he said. “So she killed all the stuff that would have spoiled it, but didn’t get hot enough to take out the spores.”
“It doesn’t often look spoiled,” he said of improperly canned vegetables.
He noted that pickling vegetables with acid or salt and preserving fruits with sugar is enough to retard spore growth without a pressure bath, assuming there’s enough acid, salt or sugar.
“There are very passionate people who are maybe not doing canning with science-based recommendations,” said Chapman, who has studied how people preserve food.
He said that when he’s asked canners where they learned to can, they tell him the knowledge has been passed down rather than learned in a home economics class or a workshop that’s strong on the science.
“We’ve seen in other cases where [a] family link perpetuates error,” said Chapman, who said there are plenty of books, classes and online instructions from agricultural extension services.
He also said it’s important to follow recipes that have been tested, because factors such as temperature, the amount of air left in the jar or the proper level of acid are vital details.
“Of the botulism cases we see that are food borne, the majority we see are home canning,” he said.