MicroVal has approved the issuing of its first certificate for a Shiga toxin-producing Escherichia coli (STEC) detection method. bioMérieux GENE-UP EHEC detection method is validated as an equivalent alternative method to ISO/TS 13136 standard reference method to detect shiga-toxin-producing Escherichia coli (STEC) and the detection of shiga-toxin-producing Escherichia coli (STEC) from O26, O103, O111, O145 and O157 serogroups in raw meat (except poultry), raw milk and raw milk cheeses. The validation was performed by the MicroVal expert lab ADRIA Développement.
The validation of GENE-UP EHEC turned out a very elaborate process. Meat products, by using sample sizes of 25g and 375g, were analysed using 3 different enrichment protocols of which 2 with a short enrichment time. For the detection of STEC from O26, O103, O111, O145, and O157 serogroups, two extraction procedures before the PCR assays were included in the study: a mechanical cell disruption procedure (bead-beating) and the VIDAS® ESPT assay for the specific immunocapture of the targeted serogroups.
For confirmation of positive PCR assays, in addition to a direct isolation procedure on selective agars, the VIDAS® ESPT assay was also used to facilitate the recovery of the specific strains by limiting the background flora on selective agars. The multiplication of enrichment, extraction and confirmation protocols made this study highly challenging but comprehensive with more than 4,000 alternative PCR assays for the screening step. And finally, the interlaboratory study included 17 collaborators from 14 laboratories. Each collaborator performed the whole method from sample treatment to the final confirmation step.
Shiga toxin-producing Escherichia coli (STEC) are an important cause of food-borne illness. These pathogens can be responsible for gastrointestinal diseases ranging from diarrhea to haemorrhagic colitis and haemolytic uremic syndrome. As a result, the food industry needs fast, sensitive and complete methods for STEC detection to ensure a safe food supply. The certificate, number 2018LR84, can be found on the MicroVal website , together with its supporting summary report.
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