Kate Stoeckle and Louisa Strauss really love sushi. They like it so much that they conducted a major scientific experiment on their favorite food.
While still juniors at Trinity School in Manhattan, Stoeckle and Strauss collected 60 samples of sushi from New York restaurants and delis and sent them to be DNA-tested to see if the labels matched up with the actual fish.
Their findings? Twenty-five percent of the samples were mislabeled.
“We didn’t do the study with the intention of catching mis-labelers,” says Strauss, 18. “We were surprised, but now we have more knowledge about what we’re eating.”
Stoeckle first got the idea from her father, a biologist at The Rockefeller University and an early advocate of DNA bar coding. While he works with birds, his daughter wondered if the same technique could be applied to fish.
Stoeckle and Strauss, now freshmen at Johns Hopkins University, got samples from four restaurants and 10 grocery stores in Manhattan, cut small pieces of fish, and preserved them in alcohol. They sent those off to the University of Guelph in Ontario, Canada, where a graduate student was working on the Fish Barcode of Life Initiative. He compared the samples to its DNA library of 30,562 bar codes.
“I like to think of the DNA bar coding method as a big Google search,” says Stoeckle, 19. “But instead of a simple word, you’re typing in a 652-letter code to match up.”
The database doesn’t have all fish species, so only 56 samples could be identified and, out of those, 13 were mislabeled. They found that sushi labeled as “white tuna” was actually Mozambique tilapia, “Mediterranean red mullet” was really spotted goatfish, and “red snapper” was actually Acadian redfish, an endangered species.
“We weren’t even sure if the method would work, so we were surprised,” Stoeckle says. “Especially about the endangered species being used.”
While DNA bar coding is a pretty standard technique for scientists, the ease with which two amateurs were able to get these results makes this case unique. Stoeckle and Strauss’s story was featured in The New York Times and their findings were published in Pacific Fishing magazine in September.
But the girls insist that they are not science buffs. Stoeckle takes classes in cognitive psychology at Hopkins, while Strauss does theater and wants to be an art history major. “This was a great way to bring a huge scientific endeavor down to a simple level,” says Strauss.
On campus some of their classmates call them “the sushi girls,” but most of their professors have no idea about the experiment. They said they’ve tried sushi from local places, like Edo Sushi in Harborplace and Niwana in Charles Village and have liked the results.
So should local sushi spots be worried?
“It would be interesting to see how Baltimore’s sushi compares to New York City,” says Stoeckle. “I think there’s always more room for exploring.”