Survival of some Probiotics in Bio-Yoghurt Production

Viability of Lactobacillus acidophilus (L. acidophilus) and Bifidobacterium bifidum (B. bifidum)incorporated with yoghurt culture in three combinations of starter cultures; Treatment 1 (yoghurt culture + L.acidophilus), T2 (yoghurt culture + B. bifidum) and T3 (yoghurt culture + L. acidophilus + B. bifidum) were studied.Analyses of pH, titratable acidity (TA), syneresis, acetaldehyde content and sensory evaluation after 1, 3, 7, 14 and 21days of cold storage of yoghurt were under taken. Counts of L. acidophilus was recorded 5.85 log10 cfu g-1 in T1 whichwere higher than counts in T3 (5.79 log10 cfu g-1) at the end of storage period. On the other hand, the viability of L.acidophilus and B. bifidum was stable until 14 days of storage period. The results showed that the addition of B. bifidumto yoghurt culture (T2) increased TA of bio-yoghurt comparing with addition of L. acidophilus (T1). Syneresis in alltreatments was in the range of 20 to 33% and it was found higher in T3 than control. The highest sensory values were incontrol, T1 and T2 until the end of 14 days of storage period.