Quantitative Analysis of Chicken-, Porcine- and Bovine-Derived Ingredients in Sausage Products by Droplet Digital Polymerase Chain Reaction
LIU Libing, CHEN Minna, SUN Xiaoxia, ZHANG Yiqin, FU Qi, QIAN Yunkai, ZHOU Wei, GUO Chunhai, WANG Jianchang
1.Technology Center of Shijiazhuang Customs, Shijiazhuang 050051, China; 2.Logistics Management Center of Shijiazhuang Customs, Shijiazhuang 050051, China; 3.Technology Center of Qinhuangdao Customs, Qinhuangdao 066002, China; 4.Hebei Food Inspection and Research Institute, Shijiazhuang 050200, China
Abstract:A droplet digital polymerase chain reaction (ddPCR) assay based on the transforming growth factor beta 3 gene of chicken, the porcine prion protein gene and the bovine growth hormone gene as the target genes were developed for the quantitative detection of chicken-, porcine- and bovine-derived ingredients in sausage products. The results showed that the established assay was highly specific for the detection of chicken-, porcine- and bovine-derived ingredients, but not for other tested animal components. Based on the linear relationship of DNA concentration (ng/μL) with meat mass (mg) and the number of gene copies per unit volume (copies/μL), the linear equations between meat mass (x1) and the number of gene copies (y2) were established as follows: x1=(n*y2)/273.946 - n/886.557 + 0.216 for chicken;x1=(n*y2)/64.950 + n/60.644 + 0.215 for pork;x1=(n*y2)/62.839 + n/12.646 + 1.218 for beef (where n is dilution factor). The ddPCR assay was used for the quantitative detection of 64 samples of different kinds of comercially available sausages. It was found that one of these samples, labelled as containing only pork, contained 18.68% chicken-derived ingredients. The ddPCR assay could allow accurate and quantitative analysis of chicken-, porcine- and bovine-derived ingredients in sausage, and could be used to discriminate intentional and unintentional adulteration.