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E. coli outbreak from lettuce brings traceability issues to light: Expert

Dalhousie University professor says blockchain technology could mitigate sourcing issues

A Canadian expert in food distribution says he is surprised by how long it is taking for a recall to be issued after one death and dozens of illnesses in recent weeks have been linked to romaine lettuce contaminated with E. coli.

Sylvain Charlebois, a researcher in food distribution and policy at Dalhousie University, says these kinds of outbreaks are particularly dangerous during the holiday season, when people have busy schedules and generally do not watch what they eat.

Public health officials first warned of the E. coli outbreak last month, saying 21 illnesses reported in three provinces were linked to romaine lettuce. Since then, one death and 40 illnesses have been reported in five provinces.

The Public Health Agency of Canada is now advising people in Ontario, Quebec, New Brunswick, Nova Scotia, and Newfoundland and Labrador to consider other types of lettuce until more is known about the outbreak and the cause of contamination.

Charlebois says the Canadian Food Inspection Agency (CFIA) rarely issues mandatory recalls, adding most are done on a voluntary basis because companies want to maintain their reputations with consumers.

He says it's unusual for an outbreak to last more than a week without a recall, suggesting better traceability systems for produce are needed to pinpoint the cause.

"E. coli in lettuce is quite fatal -- you don't cook lettuce, so the risks are significant," he says.

Charlebois says there is a growing interest in so-called blockchain systems for grocers in which all distributors share data digitally. In a traditional supply chain system, it can take major retailers such as Walmart about a week to trace the origins of produce because it can change hands up to 10 times before it reaches the store, he says. With the blockchain system, he adds, it can take seconds.

"So when you have a situation like this, if you are using new technology, you can trace problems very quickly," he says. "But now we have a case where traceability is probably an issue... I would say the weakest aspect of our food safety system is traceability.''

The Public Health Agency of Canada recently published a notice online saying it's collaborating with its provincial counterparts, the Canadian Food Inspection Agency and Health Canada to investigate the E. coli outbreak.

"Based on the investigation findings to date, exposure to romaine lettuce has been identified as the source of the outbreak, but the cause of contamination has not been identified," the agency says. "The outbreak appears to be ongoing, as illnesses linked to romaine lettuce continue to be reported to the Public Health Agency of Canada. These illnesses indicate that contaminated romaine lettuce may still be on the market."

So far, Quebec and Newfoundland and Labrador have each reported 13 cases, Ontario has had eight, New Brunswick five and Nova Scotia one. The agency also says the E. coli cases involve people between four and 80 years old, and 70% are women.

Herb Schellhorn, microbiologist and professor at McMaster University, says the outbreak is caused by the most serious strain of E. coli, O157.

"This particular strain appeared about 40 years ago and has been a real problem and 4% of cattle are infected," he says. "Sometimes lettuce and other vegetables get contaminated and this causes a public health problem."

He says a recall shouldn't be issued until the source of the contamination can be pinpointed -- something he acknowledges is difficult with products with a short shelf life.

Schellhorn adds that advising people to avoid romaine lettuce is enough until officials can determine the cause.

"We need surveillance methodology that works really fast so we prevent human illness of this type," he says. "This particular strain of E. coli is lethal for people, but not for everybody... The chief danger is kidney and liver damage caused by this toxigenic strain of E. coli."

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