Simultaneous and Sensitive Detection of Three Foodborne Pathogens by Multiplex PCR, Capillary Gel Electrophoresis, and Laser-Induced Fluorescence

Abstract

The simultaneous detection of Staphylococcus aureus, Listeria monocytogenes, and Salmonella spp. has been approached by a new multiplex PCR-based procedure followed by capillary gel electrophoresis with laser-induced fluorescence detection (multiplex-PCR-CGE-LIF). As compared to slab gel electrophoresis, the use of CGE-LIF improved from 10- to 1000-fold the sensitivity of the multiplex PCR analysis, allowing the detection of 2.6 × 103 cfu mL-1 of S. aureus, 570 cfu mL-1 of L. monocytogenes, and 790 cfu mL-1 of Salmonella in artificially inoculated food, without enrichment. Following 6 h of enrichment, as low as 260, 79, and 57 cfu mL-1 of S. aureus, L. monocytogenes, and Salmonella, respectively, were detected. The CGE-LIF method is shown to be reproducible, providing relative standard deviation (RSD) values lower than 0.8% for analysis time and lower than 5.8% for peak areas. The multiplex-PCR-CGE-LIF proved a powerful analytical tool to detect various food pathogens simultaneously in a fast, reproducible, and sensitive way.