Specific detection of viable <i>Cronobacter sakazakii</i> in powdered infant formula by phage amplification combined with <scp>qPCR</scp> (<scp>PAA‐qPCR</scp>) assay
Yuan-song Zhang, Lei Yuan, Cao‐Wei Chen, Fedrick C. Mgomi, Zhenquan Yang, Xinan Jiao
Abstract
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 × 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.