Synbiotic Bacteria in Indigenous Indian Dairy Foods: Microbial Diversity, Functional Properties, and Health Benefits

Abstract

Indigenous Indian dairy fermented foods, including dahi, lassi, chhach, shrikhand, mishti doi and a range of Himalayan milk products, constitute a longstanding reservoir of lactic acid bacteria with demonstrable probiotic and, increasingly, synbiotic potential. These foods are prepared largely through household-level backslopping rather than defined starter cultures, giving rise to microbial consortia that differ markedly by region, substrate and preparation practice. Advances in culture-independent sequencing and metabolomics have begun to resolve this diversity, revealing consistent dominance of Lactococcus, Lactobacillus, Leuconostoc and Streptococcus genera alongside a variable accessory microbiota of environmental and, in some products, opportunistic organisms. Many of the lactobacilli and related species isolated from these products exhibit acid and bile tolerance, antimicrobial and bacteriocinogenic activity, exopolysaccharide biosynthesis and the capacity to generate bioactive peptides during fermentation, properties that collectively underpin claims of cholesterol-lowering, antihypertensive, antioxidant and immunomodulatory action. The evolving synbiotic paradigm, which permits complementary or synergistic pairing of live microorganisms with selectively utilised substrates, offers a natural extension of these traditional foods, particularly where indigenous cereal, legume or fruit-derived substrates could be combined with autochthonous strains. This review synthesises the microbiological, functional and clinical literature on synbiotic bacteria in indigenous Indian dairy foods, situates these findings against the wider global evidence base for probiotics and prebiotics, and considers safety, regulatory and standardisation issues that constrain translation from traditional practice to validated functional food. Persistent gaps include a scarcity of strain-level human intervention trials conducted on Indian populations, inconsistent taxonomic reporting across studies, and limited attention to antibiotic resistance determinants carried by indigenous isolates. Addressing these gaps through coordinated multi-omics characterisation and rigorously designed clinical studies would allow indigenous Indian dairy fermented foods to be positioned more confidently within the global functional food and synbiotic product landscape.