Specific detection of viable Cronobacter sakazakii in powdered infant formula by phage amplification combined with qPCR (PAA-qPCR) assay

摘要

Cronobacter sakazakii is a foodborne pathogen that has become a significant challenge to public health and poses a serious risk to food safety, especially in powdered infant formula. This study applied a novel approach combining the Phage Amplification Assay with qPCR (PAA-qPCR), amplifying the C. sakazakii phage EspYZU12 coupled with phage-specific qPCR to detect viable C. sakazakii in milk samples. Results showed that the limit of detection of 6.58 x 10(2) CFU/mL of C. sakazakii could be assayed in less than 5.5 h with phage EspYZU12 (10(3) PFU/mL). Additionally, compared with plate counting, the accuracy factor value (A(f)), the bias factor value (B-f) and the root mean square error (RMSE) of the PAA-qPCR method were 1.029, 1.026 and 1.808 respectively. The PAA-qPCR method exhibited high sensitivity, rapidity and specificity for detecting live C. sakazakii in dairy products.