Antimicrobial and antioxidant potential of indigenous lactic acid bacteria from raw goat milk and dahi

Abstract

The aim of the study was to investigate the antimicrobial activity and antioxidant potential of lactic acid bacteria (LAB) isolated from raw goat milk and dahi. Nine LAB strains were tested against four pathogens: Escherichia coli ATCC 25922, Klebsiella pneumoniae ATCC 700603, Staphylococcus aureus ATCC 25923, and Pseudomonas aeruginosa ATCC 27853. The antimicrobial activity was assessed using the agar well diffusion method, while the antioxidant potential was evaluated through the DPPH (2,2-Diphenyl-1-picrylhydrazyl) radical scavenging activity assay. Results indicated significant antimicrobial activity of all LAB strains against P. aeruginosa and S. aureus, with L. plantarum ADMH 97 and L. plantarum ADMG 1 showing the highest inhibition zones, respectively. Maximum inhibition of E. coli was observed with L. pentosus ADMH 73, whereas K. pneumoniae was most inhibited by L. rhamnosus ADMH 2 and L. paracasei ADMH 13. The DPPH assay revealed that L. plantarum ADMH 97 exhibited the highest antioxidant activity with a 75% inhibition rate, followed by L. plantarum ADMG 1 with 44.85%. These findings suggest that LAB from raw goat milk and dahi possess strong antimicrobial and antioxidant properties, making them potential candidates for use in therapeutic foods and natural preservatives.