Effects of seasonal and regional variations on the bacterial and fungal biodiversity of mares’ milk and koumiss in the Almaty and Zhambyl regions of Kazakhstan

The effect of seasonal and regional changes on the microbial diversity of mares' milk and koumiss in southern Kazakhstan was examined. Samples were collected from farms in Almaty and Zhambyl (eight samples each area) between July and October. Metataxonomic analysis of mares' milk revealed 85 bacterial species from 38 genera and 84 fungal species from 17 genera. Koumiss samples contained 33 bacterial and 23 fungal species. Lactobacillus was the dominant bacterial genus in mares' milk, while Kluyveromyces, Dekkera, and Dipodascus were the most prevalent fungal genera. Koumiss showed a similar microbial profile, with dominant species including Lactobacillus gallinarum, Lactococcus cremoris, Kluyveromyces marxianus, and Dekkera bruxellensis. Although both products shared key species, their relative abundances varied across months and regions. While mares’ milk contained pathogens and saprophytes, these were significantly inhibited after 24 h of koumiss fermentation. The findings emphasize the influence of geographic and seasonal factors on fermented dairy microbiota.