April 16, 2019 — When biology professor Jennifer McDonald got the DNA results back from her students’ experiment on fish, a high number of the fish were not what was said on the label.
As part of a class experiment at Fanshawe College, her students were sent to grocery stores and sushi restaurants in London to collect fish samples.
The class extracted the DNA and compared how many samples were actually what they claimed to be.
Of the 16 samples, they were able to sequence nine of them due to varied success rates.
Seven of the nine were misidentified, McDonald said.
“Yeah, it was a pretty high number,” she said.
A piece of fish that was labelled as red snapper came back as tilapia, something McDonald said happens all the time.
“That really wasn’t surprising. It was disappointing but not surprising,” she said. “Same with a piece of fish that was supposed to be white tuna. That is very often actually escolar and mislabelled as white tuna.”
What did surprise McDonald was when tilapia was passed off as red tuna.
“A fish like tuna has a very characteristic taste it has a very characteristic texture and for a place to actually be fooling people into thinking that they’re eating tuna when they’re really being served tilapia was really really surprising,” she said.