L. acidophilus strain 317/402 "Nariné" shows high antimicrobial activity with respect to pathogenic microorganisms. The degree of the activity of lactobacilli depends on cultivation conditions and the composition of the culture medium and its acidity, age of the culture, conditions of technological process, etc. The antimicrobial inhibition concentration of the product "Nariné", ensuring in vitro activity against Yersinia enterocolitica, Y. pseudotuberculosis, Vibrio NAG, etc., has been established.