Rapid Molecular Lateral Flow Device for Tuna Species Identification

Tuna species identification diagnostics are needed to prevent the mislabeling of tuna in commerce. Mislabeled tuna encourages economic fraud, compromises food safety, and hampers fisheries management efforts. Ranked as one of the world's most valuable commercial seafood, tuna are considered the most important and endangered fish in worldwide trade. According to NOAA statistics, the annual imports into the US of fresh, frozen, and processed tuna in 2016 had a market value of over $1.5 billion. Also according to NOAA, only about 25% of the tuna imported in 2016 are identified to the species level. The remaining 75% are labelled as NSPF or non-specified (species not labeled). This leads to significant questions this proposal will address: 1) How can the tuna industry and consumers be confident in tuna product labels when the majority of tuna imported are simply under the generic tuna label? 2) How can accurate tuna fisheries management data be obtained and documented? The need for a rapid, reliable, and accurate test to verify species of tuna from harvest to retail is critical in order to address these questions.In Phase I of this project, we showed "proof of concept" that we can develop a rapid method for tuna to differentiate between albacore tuna, and two common adulterants/substitutes for this species-- skipjack tuna and escolar. We eliminated the DNA extraction step (via direct amplification); and replaced traditional PCR amplification with isothermal amplification. In this Phase II, we will optimize these parameters and develop an easy-to-use lateral flow dipstick device for endpoint detection with results under 3 hours. We will also add additional tuna species and other common tuna substitutes onto the DNA fish stick. Our overarching goal is to deliver a commercialized easy-to-use lateral flow test that will readily distinguish the major, high-valued tuna species in commerce from one another as well as from the commonly substituted species found in commerce. The entire tuna supply chain (from harvest to consumption) has a critical and immediate need for such a test.To date, regulators and industry stakeholders that monitor product labels in commerce and fisheries management groups do not have an available tool that they can employ on-site to distinguish tuna species and potential adulterants. The device developed as part of this USDA SBIR will be commercially available to the tuna industry and regulators as a simple, rapid, test to identify tuna throughout the supply chain, with results under 3 hours (versus 5 days for existing tests) and the estimated cost will be ~$25 per test, a significant savings from current laboratory tests ($180/test) and will allow for far more product to be tested and verified.