04/14/2019 17:39 EDT | Updated 04/15/2019 13:39 EDT

Fanshawe College Class Uncovers Fish Fraud After Testing Samples

Your sushi might not be what it claims to be.

An Ontario biology professor and her class found stomach-turning results after they tested the DNA of fish samples from sushi restaurants and grocery stores across the province.

Fanshawe College Prof. Jennifer McDonald said the exercise, which mirrors testing done by food safety officials in the U.S. and Canada on products like olive oil and maple syrup, had be useful to her molecular biology students in London, Ont.

Watch: The scope of fish fraud goes beyond just Canada. Story continues after the video.

"It is the type of experiment that is not only interesting and relevant to everyday life, but also relevant to their lives as laboratory technicians when they [graduate]," she told HuffPost Canada via email.

The class sent nine different samples to a lab to look for fish fraud. The results: only two samples actually were actually the fish they were supposed to be.

Even more disturbing? One of the samples — fresh salmon from a grocery store — tested positive for body louse — a tiny insect that can spread disease and consumes dead human skin and blood.

McDonald documented the experiment in a Twitter thread.

Mislabelled fish included:

  • Tilapia, which is a white fish, was being passed off as red tuna, which suggests it was dyed
  • Rainbow trout actually being coho salmon — a more expensive fish
  • Atlantic cod — a threatened fish species — being labelled as Pacific cod
  • Rainbow trout labelled as Atlantic salmon
  • Escolar, which contains an indigestible oil that can have a laxative effect on humans, was being called white tuna.
Boston Globe via Getty Images
Albacore tuna, left, and escolar, right.

Escolar has been banned in Japan since 1977, but can be sold legally in Canada as long as it is correctly identified since "it does not pose a health risk to consumers," according to the Canadian Food Inspection Agency.

The only two samples that came back correctly labelled were rainbow trout and Icelandic cod.

"I knew about fish fraud as existing, but I wasn't aware of just how big of a problem it really is," McDonald told CTV News.

She also told HuffPost Canada that the seafood industry wasn't the only culprit.

"I hope that this starts to make people more aware about what they're eating... there are many other food products that may not be what they claim they are! I think we, as consumers, need to demand more oversight on the food supply chain not just in Canada but around the world."

Wider implications

McDonald said the results have serious implications for people with food allergies or people who avoid certain foods for cultural or religious reasons.

"As consumers, we do the best we can to avoid foods that we know are going to make us sick (or, in some cases, kill us) but if we can't trust the label or the menu, how can we know that the food we're eating is safe for us before it's too late?" she said.

She pointed to imitation crab as an example, which contains gluten and could be dangerous for people with a gluten intolerance or allergy. Imitation calamari, which is made of pig anus, could be inadvertently eaten by those who don't eat pork products meat for cultural or religious reasons, she said.

Getty Creative
Salmon fillets.

In a study last year, 44 per cent of seafood tested in five cities by Oceana Canada was mislabelled. Similar surveys have found the results to be as high as 50 per cent.

More from HuffPost Canada:

McDonald said she ate fish the same night that her class unpacked the experiment's results.

"I think the take-home message here is: how much do you trust your sushi chef, their supply chain, and your fishmonger? Buying whole fish, especially if the head is still attached, is one quick way of ensuring that you're getting what you pay for."

Check your sources

She also advised concerned consumers to be more vigilant about where their food is being sourced.

"Buying certified-sustainable fish is also a good way to go if you want to ensure that what is on the label is what you're eating... On average, though, for most people it shouldn't change their eating habits. Does it taste good? Then eat it! If you have food-based allergies, make sure you're extra vigilant about what you eat, and maybe skip the fish when you're at a restaurant unless the chef can tell you the source of their fish."

McDonald wants to repeat the experiment with her students next year, but with even more sample variety, such as scallops, crab, lobster and canned tuna.

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