Evaluating the Effect of Temperature and Pooling in Detection and Isolation of the Major Non-O157 Shiga Toxin–Producing Escherichia coli Serogroups from Meat Samples with the Use of Alternative and Standard Methods

Abstract

Pathogenic Shiga toxin–producing Escherichia coli (STEC) are an important cause of foodborne illness. The detection of STEC 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 successfully applied to control STEC. The aim of this study is to evaluate the effect of temperature and pooling in detection and isolation of the major non-O157 STEC serogroups from meat samples with the use of alternative and standard methods. Bovine meat was experimentally inoculated with one of the “Top 6” non-O157 STEC strains (O26, O103, O111, O145, O45, and O121). Both ISO TS 13136:2012 and a novel alternative method were implemented to evaluate the impact of temperature and pooling. An increase of the enrichment temperature to 41.5 °C allowed the detection of the spiked strain in 10% more samples compared to enrichment at 37 °C. The use of 25- and 375-g sample tests demonstrated no statistically differences between both methods. And finally, this alternative method appears easy to use and time-saving for routine laboratory use.