A biology teacher has just exposed sushi restaurants for committing fish fraud

When you’re a chef who serves raw fish, there is precious little wiggle room. Unlike other cooking traditions, sushi does not afford the luxury of burying substandard ingredients under layers of spices and seasoning in the hope that no one notices what they’re eating is garbage. Great sushi is, at its heart, honest. Anything less should, in theory at least, be relatively easy to spot.

Credit: Pixabay/Robert-Owen-Wahl

Given that there is nowhere to hide at a sushi counter, it must take serious self-confidence for anyone to attempt any kind of fishy fraud. It takes a very special kind of con artist to look a customer dead in the face and tell them that they’re eating salmon when they’ve just been served slices of orange-dyed fish fingers. Yet, according to a college biology professor and her team of investigative students, that may be exactly what’s happening across the food industry.

Last month, Dr Jennifer McDonald, a professor at Fanshawe College in London, Ontario, was looking for a way to “spice up” her Molecular Biology lab class. As fascinating as the microscopic study of organic matter undoubtedly is, McDonald was finding it difficult to prove to her students just how this field could relate to the real world. It was then that she had a brainwave. She decided to embark upon “a practical exercise that integrated the theory portion of the lab with something that was really hands-on, relevant to today’s biology world, and relevant to what my students may one day be doing as Laboratory Technicians when they graduate.” Her students began to test the fish at local sushi restaurants to see whether they matched up to their labels.

The results of the experiment were concerning to say the least. As Dr McDonald revealed in a series of tweets, her students were able to gather 13 different samples from several prominent local sushi restaurants, from which they were able to harvest nine “pretty decent sequences” for genetic identification. Of these nine, only two were found to have been labelled correctly.

A deeper dive into McDonald’s results revealed some even more horrifying details. Students discovered sea trout and coho salmon labelled as “Steelhead” trout, tilapia incorrectly described as “red tuna”, and escolar masquerading as “white tuna”. For Dr McDonald, this last entry was particularly troubling, as escolar is known to be a leading cause of “extreme gastrointestinal distress” but crops up time and time again on menus that feature so-called “white tuna”.

However, though the misidentified fish is certainly troubling, it’s nothing compared to what the team found in a bag erroneously labelled as “salmon”. According to Dr McDonald, 200 of the 650 base pairs of DNA in that sample came not from fish but from “body louse”, implying that the fish had been riddled with parasites before it had been served to customers. As Dr McDonald put it herself, “This wasn’t a piece of garbage from a market. This was salmon “fillet” that someone paid good money for…think how [much body louse] must be in that sample to override fish DNA!”

Though the problem of fraud in the fish industry has been known for decades, the scale of it is still relatively poorly understood by the public. Experts estimate that it is currently a $50 billion global industry, with consumers all over the world. Earlier this year, a study published by the conservation group Oceana revealed that even at the world’s top restaurants, customers may not always be getting exactly what they pay for, with an estimated 21 per cent of all fish incorrectly labelled. Sushi may make the con theoretically harder to pull off and definitely isn’t the only area that has a problem.

Although her findings have helped highlight just how prolific the problem may be in the seafood industry, McDonald was quick to point out that the problem isn’t exclusively confined to fish. As she explained in an interview with Bored Panda, “The investigation of fish mislabelling in Canada started with fallout from a horse meat scandal in the EU, where ground horse meat was being labeled as beef and pork. I think it’s easy to do in the fish and seafood industry because you rarely see the entire organism (most people buy fish fillets, or pre-sliced fish steaks, or eat it in restaurants, etc.), but I think it absolutely happens in other industries. Olive oil, maple syrup, and teas (as three examples) are often cited as targets for mislabelling and food fraud.”

Despite the definitively disturbing results of her study, McDonald had a few words of advice for anyone considering swearing off seafood for good. “I ate fish again the night after we found the results! I love fish and I love sushi. I’ll stay away from anything labelled ‘white tuna’ just to be safe, but these results won’t stop me from eating it in the future! I will be much more discerning in the fish I buy at the grocery store, to look for sustainable fishing certification on the label. This increases the likelihood that you’ll get fish you can trust to be what the box or label says it is, and you can also be playing a role in helping make the fishing industry more sustainable. Look for the MSC logo on your food to know if it’s certified sustainable or not.” As with many aspects of what we eat, awareness is obviously of paramount importance.