EVALUATION OF LISTERIA MONOCYTOGENES CONTAMINATION IN RETAIL SMOKED SALMON

Abstract

The aim of this study was to assess the contamination levels of L. monocytogenes in retail smoked salmon of different geographical origin, comparing the performance of two isolation methods, ISO 11290-1 (qualitative) and ISO 11290-2 (quantitative), and also by molecular methods (16S rDNA sequencing, PCR with specific primers). Among 35 samples (7 batches, 5 samples per batch), only 1 sample from Denmark resulted positive for L. monocytogenes. The strains isolated on ALOA and Palcam Agar by the qualitative methods, were confirmed to the specie level (iap+, InlA+, InlB+), belonging to the serotype 1/2c - 3c (D2+), and positive for the virulence genes (InlC+ e InlJ+).

Keywords

• Smoked salmon, L. monocytogenes, ISO 11290-1, ISO 11290-2, 16S rDNA, PCR