Viability of Probiotic Bacteria in Yogurts Produced in Mazandaran Province Exposed to Simulated Gastrointestinal Conditions

Background and purpose: Production of functional foods is one of the most important achievements in food industry and using these products provides the convergence of two important events in life; namely receiving nutrients from the diet and promoting health for consumers at the same time. This study aimed to verify the viability of microorganisms and stability of these microorganisms in digestive conditions of the body in order to benefit from the claimed properties of these products. Materials and methods: In this experimental study, 14 samples of probiotic yogurts were collected from three dairy factories in Mazandaran province in summer 2020. The test method consisted of three main steps; determining the viability of probiotic bacteria in the samples over time, then simulating the conditions of the gastrointestinal conditions, including pH changes and exposure to pepsin and bile salts, and finally, evaluating the resistance of microorganisms after passing the conditions of gastric and intestinal simulated condition. Statistical analysis was performed using SPSS. Results: In the study of viability of Bifidobacterium and Lactobacillus, a significant difference was observed between the mean number of colonies both at different weeks and different pH levels (P