New ISO 16140-6 validation for Check&Trace Salmonella 2.0

MicroVal has approved the issuing of the certificate for Check-Points’s Check&Trace Salmonella 2.0. WFC Analytics carried out the validation study, based on ISO 16140-6, for an alternative method for the confirmation and typing of Salmonella spp. Following from the validation study, the Check&Trace Salmonella 2.0 (CTS 2.0) is considered equivalent to the reference method (ISO 6579-1 and ISO 6579-3) for the confirmation of presumptive Salmonella spp. isolated on non-selective NA and selective XLD and for typing of 59 Salmonella serovars.

The Check&Trace Salmonella 2.0 Assay is a qualitative, semi-automated real-time PCR test designed for the confirmation and typing of presumptive Salmonella isolates from enriched culture media. The confirmation procedure advances a suspected (presumptive) Salmonella result to a confirmed Salmonella spp. result or a Salmonella negative result. The typing procedure generates a serovar result or a “genovar” code both uniquely defining each bacterial isolate tested.

DNA typing differs from serotyping. With serotyping the presence of antigens on the cell surface and flagella are detected. This is based on expression of genes located on two specific segments of the Salmonella genome. The CTS 2.0 assay detects genetic variation at 21 loci scattered over the whole Salmonella genome: this generates specific Salmonella genotypes, also called Genovars. The CTS 2.0 database links Genovars to a collection of well-characterized Salmonella Serovars. A Genovar will be given as test result if there is no established Serovar for the Genovar generated by the CTS 2.0 assay.

Check&Trace Salmonella 2.0 is considered equivalent to the ISO standard (ISO/TR 6579-3:2014) for typing of 59 Salmonella serovars. The full list of Salmonella serovars is given in the certificate and validation report, available on the MicroVal website under ‘issued certificates / confirmation methods’.

New Certificate for iQ-Check™ STEC VirX

In June 2022, MicroVal has approved the issuing of the certificate for Bio-Rad’s iQ-Check™ STEC VirX kit for real-time PCR detection of virulence genes in Shiga toxin-producing Escherichia coli. ADRIA Développement has carried out the validation study of this alternative method, based on ISO 16140-2:2016, for the scope of raw meat products (excluding poultry) and raw dairy products.

STEC outbreaks are commonly associated with the consumption of raw meat, particularly beef, but also with dairy products. A sample positive for both stx1/stx2 and eae targets typically requires further testing for the identification of the major E. coli serogroups. The iQ-Check STEC VirX Kit, based on a multiplex real-time PCR system, allows the detection of the stx1/stx2 and eae virulence genes within a few hours after microbiological enrichment.

The certificate and the accompanying validation report, number 2021LR96, can be found under ‘issued certificates / alternative methods’.