Real-time PCR method based on single-copy nuclear DNA sequences for the quantitative detection of pork adulteration in processed beef products

Meat adulteration, which adversely impacts food safety, economy, and religious beliefs, has come to be considered as a matter of global concern. The lack of a standard method that can be employed to quantitatively detect the pork content in processed meat products has led to demands for an accurate and sensitive method capable of detecting the proportion of pork in processed beef products. In this study, we aimed to develop a real-time PCR-based method to accurately and quantitatively detect pork adulteration in processed beef. We used bovine and porcine species-specific sequences to design primers and probes that specifically amplified bovine and porcine genes. Our real-time PCR method was evaluated via quantitative detection of reference samples and found to be highly accurate. Sensitivity analyses indicated that the limit of detection for beef as well as for pork was as low as five copies, while the limit of quantification for beef and for pork was 0.1%. To compare qualitative and quantitative results, beef samples cross-contaminated with pork were analyzed using both quantitative and standard qualitative methods. No undeclared meat components were found among the 25 processed meat products that were analyzed to evaluate the applicability of the quantitative method. However, the beef content in some processed beef products was very low, even approaching zero. This real-time PCR method may be reliably applied for quantitatively detect pork adulteration in processed beef products. Thus, this method of ours may help promote healthy and sustainable development of meat products.