The effects of yoghurt-making process on the survival of male specific coliphage (MS2) in raw milk with different fat content, as well as the survival of MS2 during the storage of yoghurt were evaluated. All samples were analyzed for pH, acidity, and virus count. The results showed that the heat treatment of milk (85 8C, 30 min) decreased the recovery of coliphage MS2 from approximately 7 to 0.97 and 1.49 log10 (pfu/ml) in the milk samples with 2.5% and 3% fat, respectively. No MS2 could be detected in the heat-treated milk sample with 1.5% fat. The recovery of MS2 during incubation was decreased as the acidity increased particularly in milk with 1.5% fat. Moreover, during the storage time (10 days), yoghurt samples with 1.5% and 3% fat had the lowest and the highest recovery for coliphage MS2, respectively.

Keywords