Abstract
This study presents the results of testing a strain-oriented approach for the primary selection of postbiotic producers. The approach employs a morphological-tintorial screening of cultures isolated from three contrasting matrices: kumis, shubat, and sauerkraut. For kumis, a dominance of the yeast morphotype (Saccharomyces s.l.) was observed; in shubat, both rod-shaped and coccoid lactic acid bacteria were detected alongside yeasts; and in sauerkraut, lactic acid microorganisms exhibited mucoid phenotypes indicative of exopolysaccharide production. Based on combined micromorphological and colony characteristics, a collection of candidate strains was assembledthese show potential to yield postbiotic fractions with targeted functional properties (antioxidant, anti-inflammatory, immunomodulatory) and are technologically compatible with dairy products. The practical significance lies in the rapid and reproducible identification of relevant candidate strains by the proposed primary screening. It also establishes clear criteria for progressing to confirmatory identification (using biochemical and molecular methods) and defines initial parameters for producing postbiotic fractions. The findings can be directly applied in planning subsequent laboratory and technological trials for the development of functional dairy products. While the morphological approach is limited to genus-level taxonomic precision, this is addressed through planned validation using instrumental methods. Overall, this work provides a methodologically sound foundation for further selection of postbiotic producers and their integration into functional dairy product technologies.