Survival of Arcobacter butzleri during production and storage of artisan water buffalo mozzarella cheese

Water buffalo mozzarella cheese (WBMC) is a fresh stretched cheese produced from whole chilled buffalo milk. Although pasteurization of milk and the use of defined starter cultures are recommended, traditional technology involving unpasteurized milk and natural whey cultures is still employed for WBMC production in Italy. The purpose of this study was to assess the behaviour of Arcobacter butzleri during WBMC production and storage under different temperature conditions (5, 10 and 20°C). Raw milk was experimentally inoculated with one reference strain and two isolates of A. butzleri and the count was monitored during WBMC production and storage. The bacterial count of A. butzleri decreased during curd ripening (from 7.83 log CFU/g to 4.14 log CFU/g in about 4 h) and a further decrease (> 4 log CFU/g) was observed at the end of curd stretching. During storage testing, A. butzleri was never detected by direct plating whereas it was recovered from 12 of the total 162 WBMC until the end of storage testing by enrichment. The results revealed that A. butzleri is able to survive during WBMC production and storage at different temperature conditions. Consequently, traditional WBMC produced from raw milk could represent a potential source of Arcobacter infection for humans