Behaviour of Arcobacter butzleri and Arcobacter cryaerophilus in ultra-high temperature, pasteurized and raw cow’s milk under different temperature conditions

The growth and survival of Arcobacter butzleri and Arcobacter cryaerophilus in milk were investigated at different storage temperatures. Three strains of each Arcobacter species were inoculated into ultra-high temperature (UHT), pasteurized and raw cow’s milk and stored at 4, 10 and 20°C for six days. The survival of Arcobacter spp. during storage was evaluated by a cultural method. Results clearly showed that A. butzleri and A. cryaerophilus remained viable in milk when stored at 4 and 10°C for a period of six days. When UHT and pasteurized milk were stored at 20°C the A. butzleri count increased, with a longer lag-phase in pasteurized milk, whereas the A. cryaerophilus count increased in the first 48 hours then rapidly decreased to below the detection limit on the sixth storage day. When raw milk was stored at 20°C the A. butzleri and A. cryaerophilus counts decreased from the first day of storage and no viable bacteria were recovered on the last day of storage. Generally A. butzleri displayed a significantly better growth and survival capacity than A. cryaerophilus in milk. The present study is the first to assess the survival and/or growth of A. butzleri and A. cryaerophilus in milk. The evidence suggests that in case of primary contamination of milk or secondary contamination due to post-processing contamination, milk can act as a potential source of Arcobacter infection in humans and could have public health implications, especially for raw milk consumption.