فهرست نشریات علمی دسترسی آزاد ایران

In this study, the viability of Lactobacillus bacteria in probiotic dairy products sold in Qazvin city within two periods was examined. Eighteen samples of dairy products (yogurt, cheese, and kefir drinks) labeled with probiotics from different brands of various companies in Iran were prepared. Dilutions were prepared appropriately from each sample and inoculated into MRS Bile Agar culture medium as a pour plate culture procedure. After incubation, the colonies were counted and checked to see if the standards of the Iranian National Standardization Organization (INSO) (min 106 CFU/gr) were met. Then, to perform probiotic confirmation tests, each colony characterized different morphological was examined regarding catalase and Gram staining tests. The average count of live Lactobacillus showed that out of eighteen samples of probiotic dairy products, only one sample (5.5%) had the minimum number of bacteria according to INSO. In the yogurt, none of the samples could grow in the bile culture medium. In the cheese, none of the samples had the minimum number of viable bacteria according to the standard. Regarding the kefir drink, only one sample had the minimum number of live bacteria based on the standards, in the first week after the production date. In most of the dairy products labeled as probiotic, the average count of Lactobacillus with the ability to grow in bile, is lower than INSO measurements, which is at least one million bacteria per gram of a product.