[page 88] [Italian Journal of Food Safety 2015; 4:4585] Behaviour of Listeria monocy-togenes and Escherichia coliO157:H7 during the cheesemaking of traditional raw-milkcheeses from Italian Alps

The behaviour of Listeria monocytogenes and Escherichia coli O157:H7 was studied dur-ing the manufacture and ripening of two tradi-tional Italian Alps cheeses. Each cheese type was manufactured in a pilot plan from raw cow milk (without the addition of starter cultures) artificially inoculated with L. monocytogenes and E. coli O157:H7 to a final concentration of about 4 log CFU/mL. The pathogens were enu-merated throughout the cheese making and ripening processes to study their behaviour. When the milk was inoculated with 4 Log CFU/mL, the pathogens counts increased in the first time during the manufacturing process and then remained constant, until the end of ripening, or decreased significantly. Results indicate that the environment and nature of food borne pathogens affected the concentration of the bacteria during the man-ufacturing and ripening process. Thus, the presence of low cells numbers of L. monocyto-genes and E. coli O157:H7 in milk destined for the production of raw milk cheeses character-ized by a cooking of the curd less than 48°C can constitute a hazard for the consumer