Occurrence of Listeria monocytogenes and Salmonella spp. in meat processed products from industrial plants in Southern Italy

The main goal of the present investigation was to assess the microbiological safety of two typical meat-derived products, i.e. raw pork sausages and entrails lamb rolls, produced in Salento (Apulia, Southern Italy). Analyses were carried out for 7 years (from 2008 to 2014) and a total number of 6720 samples was collected by specialized personnel. The presence of Listeria monocytogenes and Salmonella spp. was detected by a PCR-based assay, combined with culturing in enrichment broth. The prevalence of L. monocytogenes was assessed in 2.4% entrails lamb rolls and in 4.2% raw pork sausages samples, whereas the occurrence of Salmonella spp. was revealed in 2.7% lamb rolls and in 3.5% pork sausages. A statistically significant seasonal variation was found in the occurrence of L. monocytogenes; in fact a higher number of samples contaminated by this pathogen was recorded in spring and autumn. On the contrary, no significant seasonal changes occurred in the prevalence of Salmonella spp. The data reported indicate that, due to the presence of these pathogens, the Italian food processors need to improve the microbiological monitoring of the processing chains, in order to guarantee health safety.