Survival of Lactobacillus acidophilus and Bifidobacterium lactis in Probiotic Yogurts

Background and Objective: The required amount of Lactobacillus acidophilus and Bifidobacterium lactis to gain beneficial effects in probiotic products is at least 106  viable probiotic cells/ml or g. Acidity is one of the important factors that affect the survival of probiotic bacteria in these products. The aim of this study was to evaluate the survival of probiotic bacteria and acidity in tree probiotic yogurts. Subjects and Methods: This study was conducted on probiotic yogurt samples from A, B and C companies to evaluate the survival of Lactobacillus acidophilus and Bifidobacterium lactis and the acidity during storage. The pour plate method of culture was used in anaerobic incubation conditions, at 37 ° C for at least 72 hr were mentioned. Results: The final number of probiotic bacteria in all of the yogurt samples were significantly decreased (P=0.00).  Acidity of all of yogurts was significantly increased. The total count of bacteria in A yogurt was more than two others after 20 days. Conclusion: It seems that selected useful combination of probiotic bacteria that reduced acid production, improve the viability of the them. Also the use of the technology such as drying, encapsulation and adding prebiotic may be increases the survival of probiotic bacteria.