Bacterial diversity of traditional fermented food, Idli by high thorough-put sequencing.

The bacterial composition of naturally fermented Indian food, Idli was studied by high-throughput Illumina amplicon sequencing at different taxonomic levels. Metagenomic investigation revealed fold change with respect to some of the phylotypes in 06th to 12th h of fermentation, suggesting the synergistic mode of nutrition. After 12th h fermentation, bacterial populations were stabilized towards 15th h fermentation. The bacterial phyla found as Firmicutes, Fusobacteria, Proteobacteria, Actinobacteria, Bacteroidetes and others in various proportions with respective to fermentation time. Among these Firmicutes and Proteobacteria were the predominant bacterial associates in this product. Initially at 0th h time interval Firmicutes (7%) and Proteobacteria (93%) were present adequately in the product which has been changed to Firmicutes (68%), Proteobacteria (31%) at the end of the fermentation (15th h). Phylum Firmicutes represented various major genus such as Lactococcus, Weissella, Lactobacillus, Enterococcus, Bacillus and Macrococcus whereas Proteobacteria revealed the presence of Enterobacter, Erwinia, Serratia, Pseudoalteromonas, Vibrio and Klebsiella genus. Co-occurrence and Co-exclusion network were developed to ensure the positive and negative association in the eubacterial genus detected in entire batter fermentation event. Some genera like Weissella, Lactococcus and Enterococcus are showing increase in abundances in auxiliary succession events can be established for starter culture development. Supplementary material: The online version contains supplementary material available at 10.1007/s13197-022-05421-4. © Association of Food Scientists & Technologists (India) 2022.