ISOLATION, CHARACTERIZATION AND PRESERVATION OF LACTIC ACID BACTERIA (LAB) FROM MAZANDARAN PROVINCE TRADITIONAL FOODS AND SURVEY OF THEIR IN-VITRO PROBIOTIC ACTIVITY

Background and Aim:Probiotics are defined as live microorganisms, which when administered in sufficient amounts, admit a health benefit on the host. Health benefits have mainly been associated with specific probiotic strains from lactic acid bacteria. Because of the benefits that probiotics brings to their host, isolation and identification of them from fermented food sources are in great consideration these days. In addition, the flavoring and nourishing properties of native bacteria are more desirable for native consumers. Therefore, we try to isolate and introduce probiotic native species from traditional foods of north province, Mazandaran, Iran.Methods:In this study, we isolate LAB on MRS and M17 agar under anaerobic condition. Microscopic and macroscopic morphological analysis were then carried out on isolated strains and Non-LABs are omitted at this step. In-vitro probiotic assay like bile and acid tolerance, hemolysis and catalase activity, tolerance to gastric juice, etc was determined according to INSO19459. Finally, the positive probiotic strains were preserved using cryopreservation technique.Results:339 LAB strains were isolated and examined in this study. Morphological analysis showed that 50, 91 and 198 of the isolates have coccid, coccobacilli and bacilli morphology respectively. Bacilli strains were selected for probiotic assay and the resulted positive ones are 25 isolate.Conclusion:: Rich biodiversity of natural dairy products can be considered as good sources of new LAB species. Therefore, we can focus on local dairy products for new LAB strains, which their nourishing properties are more desirable for native consumers.

Keywords:

Mazandaran province , Lactic acid bacteria , probiotic , Traditional food