Abstract: One typical way of meat adulteration is by adding low-priced meat ingredients into high-priced meat products. In this study, a duplex droplet digital polymerase chain reaction (ddPCR) method was developed to accurately identify bovine-derived ingredients in meat products. By analyzing the single-copy β-actin gene sequences of 14 animal species, bovine-specific primers and probes as well as universal primers and probes for animal-derived ingredients were designed to develop a duplex ddPCR system. The formula to calculate the relationship between the mass of bovine-derived ingredients (M, mg) and the number of copies of specifically amplified genes (C, copies/μL) was established as follows: M = 0.033C + 2.37. The results of this method for mixed meat samples containing a known amount of beef and different beef cuts basically agreed with the actual values. Moreover, the relative copy number was helpful to judge whether beef products could be adulterated with non-bovine-derived ingredients. The developed method was successfully applied to detect the adulteration of commercial beef products. We believe that this method will provide technical support for the quantitative detection of adulterated beef products and grading and identification of meat mixtures from different animal specices.

Key words: bovine-derived component; duplex droplet digital polymerase chain reaction; quantitative determination; meat adulteration