Species identification of commercial jerky products in food and feed using direct pentaplex PCR assay

The direct pentaplex PCR assay was developed for simultaneous identification using species-specific primer sets and a universal eukaryotic primer set in processed jerky products without DNA extraction. The specific primer sets of target meat species amplified the expected 83-, 133-, 166-, and 204-bp PCR products for pork, chicken, beef, and duck, respectively, and obtained no cross-reactivity against a total of sixteen animal species. A universal eukaryotic primer set amplified a 99-bp conserved fragment in all meat species. To evaluate the sensitivity of this assay, the different percentages of jerky samples were prepared with the meat species having the possibility to be mixed. Adulterated beef jerky samples contaminated with 0.1, 0.5, 1, 5, 10, and 50% pork and adulterated duck jerky samples contaminated with 0.1, 0.5, 1, 5, 10, and 50% chicken were prepared in a laboratory. The detection level of direct pentaplex PCR was below 0.1% pork in adulterated beef jerky and 0.1% chicken in adulterated duck jerky. The optimized assay was also applied to the analysis of commercial food and feed jerky products. The meat species in commercial jerky products were successfully identified without DNA extraction.