Insights from 30 years of Salmonella proficiency testing
Microbiological criteria for Salmonella testing
Regulatory requirements reflect the strong influence of matrix properties on Salmonella survival and recoverability. These regulations specify presence/absence requirements or allowable numbers per sampling unit, and vary according to the food category, processing steps and intended use (ready-to-eat vs intended to be cooked). In most foods, Salmonella must be absent in the portion tested. A notable exception is carcass sampling, where subsequent processing steps are expected to reduce risk.
Evolution of detection methods
Over the past three decades, Salmonella detection has shifted markedly as laboratories have increasingly moved to automation and rapid methods . More than 100 validated methods are now available through AOAC International , Association Française de Normalisation (AFNOR) and the MicroVal certification scheme , and participant choices increasingly reflect this breadth. In the AXIO PT Salmonella testing dataset (digital records from 2009 onwards), PCR use increased from 7% to 19%, while traditional culture workflows fell from 49% to 31%. Chromogenic agars have also become more common, helping simplify colony identification. Despite these changes, performance shortfalls in the AXIO dataset were more often linked to atypical phenotypes than to the method selected. This reflects the stringent, matrix-specific validation requirements of the ISO 16140 series, under which presumptive positives must be appropriately confirmed using validated procedures. Confirmatory techniques have also advanced : traditional biochemical and serological tests are now frequently supplemented – or replaced – by MALDI-TOF MS and, increasingly, next-generation sequencing.
Salmonella detection methods used in AXIO PT schemes
Enrichment/culture ISO 6579 PCR VIDAS Chromogenic agar 3M Molecular Detection System DuPont BAX ELISA Rapid Test (Various) Other
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