In-House Validation of a Rinse-Membrane Filtration Method for Processing Fresh Produce Samples for Downstream Cultural Detection of Salmonella, Escherichia coli O157:H7, and Listeria

摘要

More efficient sampling and detection methods of pathogens on fresh produce are needed. The purpose of this study was to compare a novel rinse-membrane filtration method (RMFM) to a more traditional sponge rubbing or stomaching method in processing jalapeno peppers and cantaloupe samples for detection of Escherichia coli, Salmonella enterica, and Listeria monocytogenes. For jalapeno peppers inoculated with 10~6, 10~4, and 10~2 CFU of each pathogen and cantaloupes inoculated at 10~6 and 10~4 CFU, all pathogens were detected in all (100%) samples by RMFM at a 10-mL filtration volume, as well as by the stomacher and sponge rubbing methods. However, for cantaloupe inoculated at 102 CFU, detection differed by pathogen: S. enterica (20% RMFM, 60% stomacher, and 20% sponge), L. monocytogenes (40% RMFM, 60% stomacher, and 20% sponge), and E. coli O157:H7 (100% RMFM, 75% stomacher, and 75% sponge). When RMFM was compared with the other methods, in accordance with guidelines in the International Organization for Standardization 16140:2003 protocol, it produced values ＞95% in relative accuracy, relative specificity, and relative sensitivity. Overall, the RMFM performed similar to or better than the . homogenization and sponge surface rubbing methods and is a good alternative for processing large numbers of produce samples for bacterial pathogen detection.