Seafood fraud tackled by handheld sensor
Scientists created a real-time nucleic acid sequence-based amplification assay (RT-NASBA) for the analysis of fish tissue in the field.
They demonstrated that the field sensor could discern 80.3% (49 out of 61) of groupers on the 2014 FDA Seafood List from potential impostors.
Commercial moves
The technology is being commercialized by PureMolecular under the name GrouperChek (trademark pending).
Assays for other seafood species are being developed and some, for non- seafood problematic species such as Karenia brevis (red tide-causing organism), noroviruses and enteroviruses, already exist.
The handheld instrument is a portable version of the lab-based benchtop model previously developed and is only slightly less sensitive.
From beginning sample preparation to final data, readout can be accomplished in 30–90 minutes.
The RT-NASBA assay was integrated with a handheld heated fluorometer named QuadPyre, which is a refined evolution of a prototype sensor developed by the group.
“We have also devised a simple and inexpensive method for the field purification of RNA from fish tissue allowing the entire analysis to be performed in the field in less than 80 minutes,” said the researchers.
“We believe this technology will provide a useful on-site screening tool to aid seafood processors, distributors, retailers and restaurateurs in remaining compliant with compulsory FDA regulations on salable grouper species.”
Fraud potential
The US Food and Drug Administration allows 64 species of fish to be labeled as "grouper."
This wide diversity makes it difficult to tell between legally sellable groupers from restricted species.
Increases in international trade and global seafood consumption and fluctuations in the supply of different seafood species have resulted in fraudulent product mislabelling, said the researchers.
Standard genetic methods such as DNA barcoding requires technical expertise and long turnover times and required instrumentation is not practical for on-site analysis of seafood, they added.
Developers hope it will help seafood purchasing and commerce regulation staff to close the inspection gaps and better combat seafood mislabeling fraud.
“We believe there is some utility for the field RT-NASBA assay to be able to diagnose grouper substitution on cooked tissue at the point of restaurant service where the fillets can be more readily masked with breading, crusting, or sauces.”
Source: Food Control, volume 53, July 2015, pages 81-90
Online ahead of print, DOI: 10.1016/j.foodcont.2015.01.022
“A handheld sensor assay for the identification of grouper as a safeguard against seafood mislabeling fraud”
Authors: Robert M. Ulrich, David E. John, Geran W. Barton, Gary S. Hendrick, David P. Fries, John H. Paul
