Identification of Adulterated Animal-derived Ingredients in Edible Animal Viscera Based on Capillary Gel Electrophoresis and DNA Barcoding Techniques

A DNA barcoding method with cytochrome C oxidase subunit I sequence (COI) was developed to identify 7 adulterated animal-derived components (including pig, cattle, sheep, chicken, duck, goose and rabbit) in edible viscera products. Samples were cleaned with physiological saline and pretreated by vacuum freeze drying before DNA extraction and amplification. PCR products were confirmed by capillary gel electrophoresis analysis system, and the cloned sequencing results were submitted to the local database (Viscera) for comparison. The universal primer set COI-A was used for the amplification, and the amount of DNA template and annealing temperature were optimized. Meanwhile, the minimum adulteration percentage of 19 edible viscera adulteration models was validated and examined. Results showed that the 5 viscera sources from 7 animal species can be completely amplified under the above conditions, the optimal DNA template volume and annealing temperature are 2 μL and 53 ℃ respectively, and the minimum detection percentage of adulterated components was 5%. The method is sensitive and reliable, which can be used for the identification of adulterated 7 animal-derived components in the edible viscera products.