Ensuring seafood identity: Grouper identification by real-time nucleic acid sequence-based amplification (RT-NASBA)

Abstract

Grouper are one of the most economically important seafood products in the state of Florida and their popularity as a high-end restaurant dish is increasing across the U.S. There is an increased incidence rate of the purposeful, fraudulent mislabeling of less costly and more readily available fish species as grouper in the U.S., particularly in Florida. This is compounded by commercial quotas on grouper becoming increasingly more restrictive, which continues to drive both wholesale and restaurant prices higher each year. Currently, the U.S. Food and Drug Administration recognize 56 species of fish that can use “grouper” as an acceptable market name for interstate commerce. This group of fish includes species from ten different genera, making accurate taxonomic identification difficult especially if distinguishing features such as skin, head, and tail have been removed. This is leading regulatory agencies to employ genetic identification methods which tend to have much higher species-level resolution than phenotypic methods. Standard genetic identification methods are highly technical and require expensive lab-based equipment to perform, which often leads to longer turnover times. We have developed a generic grouper assay that detects the majority of the grouper species listed on the 2011 FDA Seafood List, including all of the species found in Florida waters. This assay is based upon real-time nucleic acid sequence-based amplification (RT-NASBA) targeting mitochondrial 16S rRNA for the accurate detection of grouper. This assay can be performed in fewer than 90 min with little potential for cross-reactivity from non-target species.