Suspect Sushi?

DNA tests by a group of researchers has found that sushi and other fish have been regularly mislabeled. That's not a good thing, especially when the mislabeling results in paying more than you should:

After collecting samples from four restaurants and 10 grocery stores, spending about $300, the teens sent them to the University of Guelph in Ontario, Canada, where the Barcode of Life project began and where a graduate student had agreed to conduct the genetic analysis.

The girls' samples were compared with the global library of 30,562 bar codes representing nearly 5,500 fish species.

According to Mark Stoeckle, DNA is extracted chemically. The bar code gene, a chemical code, is amplified in a process called Polymerase Chain Reaction.

A machine examines the DNA sequences called bases, which are a series of letters, A, G, C and T, and then digitally matches them with a library of DNA bar codes or other series of letters. The bar code itself is very long, with 648 letters.

The results showed that 25 percent of the girls' samples were mislabeled: half of the restaurant samples and six out of 10 grocery store samples.

In every case, less desirable or cheaper fish was substituted for its more expensive counterpart, Stoeckle said. She and her father would not divulge the names of vendors, citing a fear of lawsuits.

"It's not the fishermen, and it might not even be the restaurants," she said. "Most likely, the mislabeling is occurring somewhere at the distribution level."