Cutting procedures might be responsible for Listeria monocytogenes contamination of foods: The case of Gorgonzola cheese

Commission Regulation (EC) No. 2073/2005 established, as a food safety criterion for tolerable levels of Listeria monocytogenes in ready-to-eat foods which do not support the growth of the pathogen or with shelf life below 5 days, a maximum of 100 cfu g1. Blue-veined cheeses are among these foods because their rinds can be contaminated, and the pathogen can be transferred to the paste during slicing. The aim of this research was to investigate whether cutting procedures could be responsible for cheese paste contamination. Considering that the Commission Regulation limit is allowed when the pathogen does not grow during the shelf life, we also wanted to verify whether, in the case of positive dragging, L. monocytogenes was able to grow on cut slices beyond the limit imposed, thereby becoming a risk for consumers during storage at 4 C. Gorgonzola cheese was chosen for this investigation. The cutting simulation on artificially inoculated wheel rinds indicated that greater rind contamination corresponded to a higher percentage of contaminated paste samples. The growth of L. monocytogenes transferred to cut slices was variable relative to the physicochemical characteristics of the cheese, to the contamination level and to the time of storage. In particular, the sweet typology was able to support the growth of L. monocytogenes in the shelf life conditions considered and the quick overcoming of the limit imposed by food safety criteria would not ensure the safety for consumption.