Listeria monocytogenes survival during production and storage of water buffalo Mozzarella cheese

The ability of Listeria monocytogenes to survive during the manufacture of water buffalo Mozzarella and to grow during its shelf life was evaluated. A wild-type and a reference strain were used to contaminate raw milk. The viable count of the reference strain ATCC 9525 dropped after the stretching process, and in the cheese, it fell to below 100 cfu/g. When the wild-type strain was used, however, stretching did not appear to have any effect on the pathogen. The artificially contaminated cheeses were stored, for eleven days, at 4, 20 and 30 °C. Pathogen populations increased at 20 (2.60 log cfu/g) and 30 °C (1.95 log cfu/g)

Occurrence et survie de Listeria monocytogenes au sein de divers types de fromage - Une review

Since the publication of Regulation (EC) N°2073/2005, ready-to-eat (RTE) food allowing the devel-opment of Listeria monocytogenes, including cheese, has to be free of this pathogen in 25 g of pro-duct. This review was carried out to gather studies on the prevalence of the pathogen in varioustypes of cheese in Europe, while also including data from other continents. Given that Regulation(EC) N° 2073/2005 distinguishes cheeses allowing or not the survival of L. monocytogenes basedon the food’s pH and water activity (aw), the review also focuses on the determi nants of thisgrowth/no growth in the same types of cheese