SOURCES of Listeria monocytogenes CONTAMINATION in TRADITIONAL FERMENTED sausage PROcessing plants IN ITALY

Environmental samples, raw materials and fermented sausages produced in Sardinia (Italy) were analysed in order to investigate the prevalence and enumeration of L. monocytogenes. Isolates were identified by single PCR and characterised by multiplex PCR-based serogrouping. The contamination routes of L. monocytogenes in the plants were traced using PFGE. In addition, a quantitative assessment of the in vitro biofilm formation was carried out. Fermented sausages seem to be regularly contaminated with L. monocytogenes: results showed the ability of the pathogen to overcome the hurdles of the manufacturing process and adapt to the processing plant environments, forming biofilms.