Evaluation of the Impact of Temperature and pooling sample to Detect and Isolate the Major Escherichia coli Serogroups Producing Shiga toxin with alternative and standard methods

Abstract

Abstract Pathogenic shiga toxin-producing Escherichia coli (STEC) are an important cause of food-borne illness. The detection of STECs in finished products and during the manufacturing process has an important role as part of verification plans, to confirm that practices and procedures described in the food safety program are successful applied to control STEC. The aim of this study is to examine the impact of increasing the enrichment temperature (from 37°C to 41.5°C) and the feasibility of pooling for the detection of “Top6", non-O157, samples in raw meat products. Both ISO TS 13 136:2012 and a novel alternative method were implemented to evaluate the impact of those new parameters. An increase of the enrichment temperature to 41.5°C allowed the detection of the spiked strain for 10% more samples compared to enrichment at 37°C. The realization of analysis by pooling the samples is compatible with the two methods used. Among the 220 food enrichments analyzed, faster results were obtained by the alternative method described in this work than by the ISO/TS 13 136 reference method. Our study showed that both methods allowed the detection and isolation of STEC strains from food enrichments.