At first glance it may not seem like such a big deal to sell flounder and call it cod. But such "seafood fraud" is being taken very seriously by the US Food and Drug Administration, which is now using genetic testing and a database of "DNA bar codes" to combat these fishy crimes, reports Scientific American's Clare Leschin-Hoar. A recent Boston Globe investigation tested 183 pieces of fish, and found that 87 were mislabeled. Escolar, which can cause health problems, is often labeled as white tuna, Leschin-Hoar says. Cheap flounder is sold as the more expensive Vietnamese catfish. And such mislabeling also makes it hard to keep track of endangered species. So FDA is now adding DNA sequencers to nine of its big labs, and has begun taking samples from retailers and wholesalers. "Officials say they are targeting cod, grouper, snapper, tuna and other high-value species, which are more likely to be substituted," Leschin-Hoar says. "The FDA has been looking into such genetic identification —called DNA bar coding— since 2007, when toxic puffer fish from China entered the country labeled as monkfish and sickened several people."
FDA has been working with researchers from the University of Guelph's Consortium for the Barcode of Life project to compile genetic bar codes of all of the world's sea species, including more than 8,200 varieties of fish. Using that information, FDA has compiled its own official database, which the agency says will help it prosecute criminals. And with the cost of sequencing coming down, the estimated cost for FDA to run a single fish sample is about $10. "The FDA's library went live on November 1st and is now available to the public and outside laboratories. It contains DNA bar codes from 250 species of frequently consumed fish," Leschin-Hoar says. "The agency is also developing a crustacean database covering species like shrimp, lobster and crab."