Rapid Quantitative Detection of Salmonella enterica Using Fluorescence In Situ Hybridization with Filter-cultivation (FISHFC) Method

Abstract

Specific detection and enumeration of Salmonella enterica in food using conventional culture-based methods (CCBM) are time consuming and labor intensive. This study was conducted to develop a rapid S. enterica detection and enumeration method by combining fluorescence in situ hybridization (FISH) with micro-colony formation culture (FISHFC). Specificity tests of the SAL343 probe for S. enterica detection revealed that SAL343-associated fluorescent micro-colonies were observed specifically for S. enterica, but not for any other organisms. This finding suggests that SAL343 is highly specific for detecting S. enterica using FISHFC. For validation, FISHFC with SAL343 was compared to CCBM, with multiple selective agar, using spiked food samples; no significant differences in enumeration were found between FISHFC and CCBM (p > 0.05). The FISHFC method allowed enumeration of S. enterica within 10 h while CCBM allowed enumeration within 5 days. Therefore, the FISHFC method has potential application for more rapid and specific enumeration of S. enterica in food samples compared to other available methods.