Researches groups have been analyzing fish samples from sushi stores and restaurants and showing that some of the fish sold are mislabeled. The specie identification is made by DNA extraction followed by PCR and DNA sequencing.
A study made by the American Museum of Natural History have found that 52% of the stores submitted to the DNA identification, from New York City and Denver, have sold mislabeled fish. A study made in Brazil, by the private company Myleus funded by my university back home (UFMG) =] , found that 24% of samples analyzed were mislabeled. Their conclusions are that most of the mislabeled fish sold were actually a cheaper fish. However, the most scare thing is that they found mislabeled samples that are a critically endanger specie and some species that can lead to allergy reactions.
The specie identification of fish by DNA sequencing is good for the consumer that wants to consume what is announced; but also for the seller, to guarantee that he is selling what he really meant.
In the links bellow you can find that article from the American Museum of Natural History and the website of the company Myleus.
