Active packaging containing nisin and high pressure processing as post-processing listericidal treatments for convenience fermented sausages

Listeria monocytogenes was inoculated on the surface of sliced fermented sausages with no added sodium salt. The pathogen was progressively inactivated during the product shelf life (90 days). Antimicrobial packaging of fermented sausages with PVOH films containing nisin induced a more pronounced reduction of L monocytogenes counts during refrigerated storage. HPP alone (600 MPa, 5 min, 12 degrees C) had no antimicrobial effect against L monocytogenes at the studied conditions. Combination of HPP with antimicrobial packaging did not produce any extra protection against L monocytogenes compared to antimicrobial packaging alone. The lack of effect of HPP on L monocytogenes was attributed to a protective effect exerted by the low water activity of the product and its lactate content. These results reflect that antimicrobial packaging with the inclusion of nisin as a natural antimicrobial could be considered as an effective method to reduce the levels of L monocytogenes in sliced fermented sausages with no added sodium salt. (C) 2012 Elsevier Ltd. All rights reserved.