Progress 05/01/05 to 10/31/05
Outputs
Our long-term goal is to develop a reproducible, cost-effective DNA-based diagnostic that will definitely distinguish four major high market-value tuna species. In this Phase I project, we performed the foundational work that supports our long term objective. Furthermore, we anticipated that this feasibility study will provide the platform for developing diagnostics for other niche markets in the food industry experiencing similar issues of fraudulent labeling and in need of species verification. While DNA is a robust target molecule, it can be susceptible to degradation under certain extraction conditions. Thus, it is important that we optimize a DNA extraction protocol that will increase the yield for recovery of DNA. The development of a diagnostic for tuna authentication necessitates addressing a series of issues including: 1). optimizing a procedure for DNA template capture that has utility for fresh meat samples suitable for its amplification by PCR, 2). testing
the reliability and reproducibility of a PCR-based diagnostic for tuna meat samples, 3). simplifying the diagnostic pattern by identifying gene-specific, species-discriminating primers for establishing four species of tuna authentication. We successfully addressed all the technical objectives put forth in this SBIR Phase I research proposal. In addition to identifying an effective DNA extraction method for tuna meat that yields high quality template for PCR analysis, we have optimized a streamlined process for tuna sample collection that provides a more rapid and facile DNA template isolation procedure while generating comparable quality DNA template for PCR-based analyses. We have demonstrated that our isolation procedure for tuna meat genomic DNA provides suitable template for PCR with our newly identified species discriminating gene-targeted primers. We identified new gene sequences from which primers were designed and used to demonstrate the feasibility and utility of a DNA-based
diagnostic. These primers are powerful new tools for species discrimination of fresh tuna products. In summary, we have developed a DNA-based method for species identification of the four major tuna species: blue fin, yellow fin, albacore, and big eye. This method can be run fee-for-service at APL Sciences for species validation. In addition, the proprietary components can be put in a kit format for public, private and government laboratories to purchase and run samples for the industry. The technology developed in this research can be extended to numerous other applications where DNA-based diagnostics are needed.
Impacts
Tuna is one of the worlds most valuable commercial seafoods. Albacore, bigeye, bluefin, and yellowfin are considered the most popular of the Thunnus species that are collectively fished in over 70 countries worldwide. Due to the exceptionally high value of bluefin, albacore, yellowfin and bigeye tuna and their diminishing stocks, there are increasing concerns regarding species substitution with lower value, lower quality species. Currently in the U.S. tuna industry, regulatory action cannot be taken to verify fresh fish species or processed products because there is no reliable test available to analytically distinguish species at the DNA level. The results of this project satisfy a critical need for the industry and the tests developed have significant value to both State and Federal regulators, other researchers and the commercial sector. Quality control issues, catch quota violations, and species substitution of tuna are viewed as emerging problems and an effective
DNA-based diagnostic for reliable species identification will provide regulators and the industry the necessary tools to take pro-active measures and enforce regulatory mandates.
Publications
- No publications reported this period
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