A Novel Fluorescence cross-priming Amplification Based on Universal Molecular Beacon for Rapid and Specific Detection of Salmonella enterica in food Samples

A methodology with rapidity and specificity is of great significance for the effective control and management of outbreaks caused by Salmonella enterica as it has presented an obvious threat to food safety and public health worldwide. In this study, we aimed to develop a tube-closed and real time cross-priming amplification assay for the rapid and sensitive detection of S.enterica and decrease the possibility of detecting false-positive signals derived from aerosol contamination or non-specific amplification caused by traditional CPA assay. The reaction system was optimized and the results showed that molecular beacon CPA (MB-CPA) method was highly specific for detection of S. enterica. The sensitivity of established assay was found to be 10 CFU/mL, 100 CFU/25 g, 10 CFU/25 g in pure culture, chicken sample without and with 6 h enrichment, respectively. And the sensitivity of MB-CPA was 10 times higher than that of real-time PCR. An application of MB-CPA assay was conducted with 78 naturally contaminated food samples to test its practicality. After an enrichment step at 37℃ for 6 h, the results showed 100% sensitivity and 100% specificity compared with standard culture-based method. Considering its rapidity, user-friendliness, cost-effectiveness, this MB-CPA assay will aid in the broader application in food industry for the detection of S. enterica in small or resource-limited food testing laboratories.