Here's why Canada's cantaloupe crisis is still going strong after 6 weeks
Salmonella outbreaks are difficult to track and the fruit has a long shelf life
The Public Health Agency of Canada (PHAC) announced a widespread salmonella outbreak linked to contaminated cantaloupes on Nov. 1. Since then, it's been investigating infections in eight provinces: British Columbia, Alberta, Ontario, Quebec, Prince Edward Island, New Brunswick, Nova Scotia and Newfoundland and Labrador.
The Canadian Food Inspection Agency (CFIA) issued three food recall warnings in November for Malichita brand cantaloupes sold between Oct. 11 and Nov. 14, and subsequently expanded its recall to include a second brand, Rudy, sold between Oct. 10 and Nov. 24. Both come to Canada from Mexico.
There have been more than 150 confirmed cases of salmonella connected to the outbreak in this country, along with some in the United States, and PHAC announced a sixth death on Friday.
"Additional salmonella infections are under investigation and more illnesses associated with this outbreak may be confirmed," PHAC said in a statement released Friday.
But the affected cantaloupes were sold weeks ago. Why are people still getting sick or dying?
Cantaloupe has a long shelf life
Cantaloupe is a surprisingly hardy fruit that can stay fresh for weeks under the right conditions. Even though several brands have been recalled, some people may still have some stowed away in their freezers.
That means the contaminated food is around longer than it was in other salmonella outbreaks linked to produce, such as bean sprouts, which spoil after a few days.
And freezing cantaloupe contaminated with salmonella won't necessarily kill the bacteria, according to the U.S. Food and Drug Administration.
"Salmonella, especially, is super tough," said Prof. Keith Warriner, who studies food sciences at the University of Guelph. "It can withstand freezing. It can withstand drying."
What's more, not everyone pays attention to recall notices, said Darin Detwiler, an associate teaching professor and food safety expert at Northeastern University in Boston.
"Many times, when we're eating cantaloupe, we don't know what farm it came from, or who's the company behind this," he said in an interview. "So that becomes problematic."
Cantaloupe's wide reach
It also took health officials some time to pinpoint the outbreak's source and announce recalls, Warriner noted. The CFIA's notices, for example, extended to some cantaloupes imported from Mexico that had already been available for several weeks.
"You could imagine how many cantaloupes are coming out and spreading across the land," Warriner said.
In addition to the eight provinces with salmonella cases in Canada, the outbreak affects hundreds of people in 42 states, according to the Centers for Disease Control and Prevention (CDC). Four people have died and more than 300 have gotten sick in the United States, where an investigation is also underway.
Salmonella can sneak up on you
Symptoms of a salmonella infection generally present themselves within three days of eating a contaminated food. People experience diarrhea, fever and stomach cramps. But some people might not develop symptoms or realize they're sick for weeks, according to the CDC.
That's one reason the scope an outbreak can be so difficult to determine. Investigators conduct interviews with affected patients, test stool specimens and sequence DNA to help identify the problem.
"More recent illnesses may be reported in the outbreak because there is a period between when a person becomes ill and when the illness is reported to public health officials," PHAC said in its statement. "For this outbreak, the illness reporting period is between two and six weeks."
Salmonella can also lead to long-term problems, including arthritis and neurological issues.
In 2012, a court in New South Wales, Australia, ordered KFC to pay $8 million to a girl who suffered severe brain damage after eating at one of the fast-food chain's restaurants with her family.
What you can do to protect yourself
While the outbreak is ongoing, Warriner advised the best way to avoid it is not to eat cantaloupe.
"What's the point in taking the risk?" he said.
And if you're hanging on to a cantaloupe at home, he referred back to the old adage: "If in doubt, throw it out."
PHAC advises the same.
Indeed, cantaloupe is one of the items that Detwiler, the food safety advocate, said to avoid in the recent Netflix documentary Poisoned: The Dirty Truth About Your Food.
Its textured skin makes it difficult to clean, and cutting through it with a knife can spread any pathogens growing on the skin into the fruit itself.
Buying cantaloupe out of season from far-away destinations allows time for pathogens to grow, he added.
Mexico's Health Department on Friday ordered the temporary closure of a melon-packing plant implicated in the outbreak.
Mexico did not say what violations were found at the plant in the northern border state of Sonora, but said testing was being done to find the source of the contamination.
With files from The Associated Press