A triplex real-time polymerase chain reaction (real-time PCR) method for rapid simultaneous detection of Salmonella (SAL), Staphylococcus aureus (SA) and Bacillus cereus (BC) was established. Primers and TaqMan probes were designed targeting the invA gene of SAL, the Sa442 gene of SA, and the Cereolysin AB gene of BC. The performance indicators of the developed method were evaluated, and actual samples of ready-to-eat meat products were detected by it. The results showed that the real-time PCR method was highly reproducible, specific and sensitive. Fifteen non-target reference strains were tested by this method and the results were all negative. The standard curves for the three pathogenic bacteria were linear over the concentration range of 10²-10⁸ CFU/mL, and the intra-assay and inter-assay coefficients of variation (CVs) were less than 2% in the quantitative tests. Without bacterial enrichment, the limits of detection (LOD) for SAL, SA, and BC were 3.8 × 10², 4.9 × 10², and 5.7 × 10² CFU/mL, respectively. After 5 h enrichment, they increased to 3.8, 4.9, and 5.7 CFU/mL, respectively. The results of the real-time PCR method for 100 actual samples were consistent with those of the national standard method, indicating that the real-time PCR method can be used for the detection of the three pathogenic bacteria in bulk ready-to-eat meat products.

A multiplex real-time polymerase chain reaction (PCR) method for simultaneous rapid detection of donkey-, horse-, pig- and duck-derived components was established. For this purpose, the Nad5, ATpase6, ATP8 and cytb were used as target genes to design specific primers and TaqMan probes, and the 18S rRNA gene was used as internal reference gene. The developed method was validated and applied to detect simulated adulterated meat products, simulated processed meat products and actual donkey meat samples. This method was characterized by high-throughput, and excellent sensitivity and specificity. The system had no cross-reaction to non-target sources when the cycle threshold (Ct) value did not exceed 35.0. The sensitivity was 2 × 10^-4 ng/μL of template DNA. The detection limit for raw and cooked meat was 0.001% and 0.01% of the meat content, respectively. The results of this method for 100 actual samples were consistent with those of the national standard method, indicating that the multiplex real-time PCR method can be used for the detection of commonly adulterants in meat and meat products.

A multiplex real-time polymerase chain reaction (PCR) method for simultaneous and rapid detection of components derived from sweet potato, cassava, potato, and corn was established. The g3pdhs gene of sweet potato and cassava, the UGPase gene of potato and the zSSIIb gene of corn were used as target genes to design specific primers and TaqMan probe, and the 18S rRNA gene was used as the internal reference gene. Methodological validation was performed, and the proposed method was applied to simulated samples with different mixing ratios and actual starch samples. The results showed that this method was high-throughput, sensitive and specific. No cross-reaction was found with 15 non-target sources. The detection sensitivity for template DNA was 3 × 10^-3 ng/μL, and the proposed method had a good linear relationship and high amplification efficiency. The detection limit for edible starch samples was 0.1%. The results of the PCR method for 50 actual samples were consistent with those of the reference method, indicating that this method could be used for the detection of common adulterants in edible starches.