Selection of robust starters from household dahi and assessment of their sensitivity to bacteriophage isolated from dairy effluents

Identifying the predominant strains of lactic acid bacteria (LAB) in dahi that are resistant to bacteriophages is essential for developing robust starter cultures. Dahi samples from two agroecological zones of Kerala were collected for isolation of LAB. Limosilactobacillus fermentum emerged as the dominant starter culture species based on sequence-based identification and technological property characterisation. Dairy effluents were screened for phages targeting L. fermentum, and 10 of 11 strains of L. fermentum showed resistance to one lytic phage isolated as part of this study. The strain ADMT 15 showed sensitivity to the phage and on subsequent genome sequencing the phage revealed its close relationship to members of the Herelleviridae phage family.