Listeria monocytogenesin Ready-to-Eat Seafood and Potential Hazards for the Consumers

摘要

The risk of exposure toListeria monocytogenes(L. monocytogenes) when consuming Ready-to-Eat (RTE) seafood was assessed in the Veneto Region (Italy). Thirty-eight samples were analyzed, each sample consisted of three subunits belonging to the same batches. The first of the three units was examined immediately, the second was stored at +4°C (for all of its shelf-life) and the third at +10°C (for the latter third of itsshelf-life) before the analysis. Chemical-physical and microbiological parameters were tested simultaneously. Culture results showed the presence of viableL. monocytogenesin 9 (23,68%) of the 38 samples analysed, 3 (33,33%) of which with a concentration >100 cfu/g. PCR tests yielded 12L. monocytogenespositive samples. Semipreserves with aw (water activity) and pH values that favourL. monocytogenesgrowth were the only ones to result positive to microbiological and PCR tests. Temperature proved to be an important factor as it limits the growth ofL. monocytogenes, including products with potentially high competitive microbial charges. Four different serotypes were recovered and ribotyping has helped to highlight the genomic variability ofL. monocytogenesstrains in food. This supports the hypothesis thatL. monocytogenescontinues to evolve genetically to the detriment of phenotypic conservation.