| Abstract | In this study fermented milks were mad from buffalos’ milk fortified with 50, 100 or 150 mg/l of ascorbic acid (vitamin. C) by 1.5% of a mixed culture of S. thermophilus, L. bulgaricus and B. bifidum. Effect of vitamin. C on some chemical and organoleptic properties and the viability of starter culture strains of the resultant products were investigated during 8 days of cold storage at 7?C±2. All fresh fermented milk products added with vitamin C resulted in higher acidity content than the control sample however the addition of vitamin C by 150 mg/kg milk was more effective in reducing the pH value during storage period than the other treatments. There was a slight effect of vitamin C on the production of total volatile fatty acids (TVFA) and acetaldehyde concentration during storage period. The maximum L. bulgaricus, S. thermophilus and B. bifidum counts were found with 50 mg ascorbic after 4 days of storage followed by a gradual reduction to the end of storage period. The addition of vitamin C to the cultured milk products increased the viability of B. bifidum count throughout storage period. The highest sensory scores that were comparable to the control were obtained by the addition of 50 mg /kg of vitamin C to the fermented milk, however the addition of 100 and 150 mg /kg extremely lowered the sensory properties of the resultant product |