Fate of Listeria monocytogenes during shelf-life of sliced salami 'Gentile' packaged in protective atmosphere - Comparison between naturally and artificially contaminated samples

摘要

A Microbial Challenge Test was set up to assess the trend and possible growth of Listeria monocytogenes in pre-sliced Salami Gentile packed in protective atmosphere, with the purpose of providing quantitative data on the evolution of potential Listeria contamination. The detection, during the preliminary test, of a salami naturally contaminated by Listeria, enabled us to monitor the evolution of the pathogen present over time and at different temperatures. MCT results showed that L. monocytogenes cannot grow in matured Salami Gentile with aw of 0.93 and pH of 5.7, even if, according to European Regulation no. 2073/2005, these parameters would make salami a suitable substrate for Listeria growth. Inhibition was recorded both at refrigeration temperatures of 4 and 8°C, and at abuse temperatures of 15, 21 and 25°C. The same results were obtained also in naturally contaminated salami where the inactivation speed increased in proportion to the rise in incubation temperature.