DNA Tests Uncover Sushi Fraud At Restaurants

tuna sushi
Photo: Is that really tuna? (LFL16 on Flickr)
The next time you order tuna at a sushi restaurant - watch out! - it may not be what you think it is. A team of scientists from Columbia University and the American Museum of Natural History conducting a genetic research project found that more than half of tuna ordered from 31 restaurants were "misrepresented" or selling endangered southern bluefin tuna. Some samples were not tuna at all, but escolar, a fish with fatty flesh that could pass as tuna but can cause diarrhea when consumed.
"A piece of tuna sushi has the potential to be an endangered species, a fraud or a health hazard," reports the authors. "All three of these cases were uncovered in this study."

The findings were actually a coincidence as the study's aim was to improve on a new method of species identification called DNA barcoding. The purpose is to collect fish DNA and to upload the information on a global database called FISH-BOL (now about 20 percent complete) so that users with a hand-held DNA reader can identify a fish in minutes.

There is plenty of potential for conservation enforcement:

Wildlife officials could use that technology to spot-check fish markets, and fine people who are selling protected species.

...but zooligsts can't seem to agree upon the best way to condense the genetic information from each fish into a concise signature. That's where this study comes into play. By checking 14 carefully selected spots on a gene called and matching them up with the database, the scientists could accurately identify any kind of tuna.

Let's hope that such measures will mean that consumers won't have to hazard a guess next time they order the mystery fish.

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