Appreciate a well-cooked tuna steak or salmon wrapped in a sushi roll? There’s a good chance the fish sitting on your plate or in your grocery store’s seafood case is not what its label says it is, according to the ocean conservancy group Oceana. So you could be paying a premium for red snapper that’s really just plain old tilapia.
University of South Florida scientists have now made a handheld device that could help fight such seafood fraud. The instrument genetically verifies whether fish being called grouper is really grouper or less expensive, potentially harmful substitutes like catfish or mackerel. A quarter of grouper in the United States is mislabeled, according to Oceana, making it the fourth most commonly mislabeled fish in the country. (Snapper was the most comonly mislabeled.)
The Oceana study found that 33 percent of the 1200-plus seafood samples taken nationwide were mislabeled. This seafood fraud costs fishermen, the U.S. seafood industry, and consumers $20–25 billion annually, it calculates. In addition, fraud allows illegally caught fish to slip into the legal seafood trade and prevents consumers from making ecologically-friendly choices.
Photo: University of South Florida
Today’s DNA barcoding methods for seafood identification analyze a sample’s DNA. While the price of gene sequencing has dropped in recent years, it still takes days and expensive lab equipment for accurate genetic identitification. The new device, on the other hand, purifies and amplifies a seafood sample’s RNA, or ribonucleic acid. The assay is simpler and works within 90 minutes. USF marine science professor John Paul and his colleagues have developed such assays to identify several microorganisms, and have now applied the technology to seafood identification.
The researchers described the technology and its application in the journal Food Control. They are now developing assays for other commercially relevant species, and they’re also commercializing it through Tampa-based spinoff PureMolecular LLC. That company plans to start selling the machines for US $2000 by this summer, Reuters reports.
Prachi Patel is a freelance journalist based in Pittsburgh. She writes about energy, biotechnology, materials science, nanotechnology, and computing.