Introduction: Isolation and identification of lactic acid bacteria from local products can play an important role in introducing unique types of probiotics. The aim of this study was to isolate lactic acid bacteria from local dairy products in Yazd city with the ability to inhibit the growth of some digestive pathogens.
Methods: In order to isolate lactic acid bacteria, culture samples were cultured on specific agronomic culture media of Agar, M17 agar, KAA and MRS + Vancomycin. The isolates were then identified based on common morphological features and biochemical tests and sugar fermentation. Evaluation of the antibacterial activity of the topsoil culture solution against four gastrointestinal pathogenic bacteria was performed by well method.
Results: Out of 29 samples of doogh and local cheese and 7 industrial samples, a total of 76 isolates were identified, among which Lactobacillus casei had the highest frequency with 41.54%. Lactobacillus casei and Lactobacillus acidophilus isolated from doogh and sheep's cheese, and Lactobacillus delbrocci and lactobacillus ramenosus isolated from sheep's butter against all pathogenic bacteria studied, namely Escherichia coli, Candida, and Staphylococcus aureus. Also, lactic acid bacteria isolated from industrial samples showed less antibacterial activity compared to local sample isolates.
Conclusion: In general, due to the antagonistic activity of lactic acid bacteria isolated from local dairy products, it is recommended to evaluate their use as probiotic bacteria.