Unmasking seafood mislabeling in U.S. markets: DNA barcoding as a unique technology for food authentication and quality control

• Mitochondrial cytochrome oxidase I (COI) region can identify fish and seafood species.
• Fish species mislabeling among restaurants is 16.3% across 3 US cities.
• Rate of mislabeling is essentially equivalent across the 3 cities.
• Rate of mislabeling at retail is lower in San Francisco Bay area.
• Mislabeling rate is lower than reported in past studies.

Seafood mislabeling has been practiced both to meet market demand, as well as for economic gain, whereby cheaper species are substituted for high-value seafood items. Traditional methods of identifying species based on fish morphological characteristics are not always practical to unambiguously identify seafood products available for purchase. The use of DNA sequencing for species identification is a reliable alternative to traditional methods like morphological determination, especially when food items have been subject to various forms of processing. Results show a rate of mislabeling among restaurants of 16.3% (28 out of 172 samples) in three regions of the United States. The rate of false labeling is essentially equivalent between these different regions. This study shows the usefulness of targeting the mitochondrial cytochrome oxidase I (COI) region to uniquely identify fish and seafood samples from across the United States.