Prevalence and risk factors of potential pathogenic Yersinia enterocolitica in Tunisian frozen ground beef through a shelf-life monitoring protocol validation

This study aims to identify and determine the prevalence of Yersinia enterocolitica in ground beef meat during conservation process. In all, 180 sample-units of ground beef from three red meat processing companies were subjected to microbial analysis. The identification and prevalence rate of Y. enterocolitica in ground beef were performed using conventional culture methods and molecular identification based on the analysis of rpoB gene. The analytical method allowed the detection of 25 (14%) positive units and the identification of 15 Y. enterocolitica strains. Biogrouping classification allowed the assignment of all the isolates to the biotype 1A. However, the assessment of phenotypic virulence markers revealed that 9 out of 15 strains were presumptively virulent. The results revealed, for the first time, the evidence of Y. enterocolitica viability within Tunisian frozen beef meat and the need to consider the investigation of this bacterium within the analytical standards of meat products and their safety evaluation. Furthermore, the rpoB gene-based method is a rapid and sensitive technique to identify Y. enterocolitica strains in meat products. Novelty impact statement This work constitutes a first report of the prevalence of Yersinia enterocolitica in Tunisian frozen ground beef during conservation. The highest frequency number of positive samples was recorded at the end of the microbiological lifetime during the conservation meat process. In view of the detection of virulent markers among Y. enterocolitica 1A biogroup isolates, pathogenicity of this bacterial group should be investigated.