The incidence of Listeria spp. in soft cheeses, butter and raw milk in the province of Bologna.

Samples of soft cheese, butter and raw milk were examined for Listeria species. Listeria monocytogenes (serotype 1, haemolytic and virulent for mice) and L. innocua (the only other Listeria sp. isolated) were each found in 2/21 (1.6%) of soft cheese samples. Five per cent of butter samples were contaminated with L. innocua. No Listeria spp. were detected in 40 raw milk samples. The results were compared with similar studies in Italy and abroad.