Phenotypic characterisation and assessment of the inhibitory potential of Lactobacillus isolates from different sources

Abstract

Six strains of Lactobacillus spp. were isolated from fermenting corn slurry, fresh cow milk, and the faeces of 
pig, albino rat, and human infant. Their inhibitory action was tested against some spoilage and pathogenic 
bacteria. Lactobacillus acidophilus isolated from milk was found to display a higher antagonistic effect with 
zones of inhibition of 6 and 15 mm against E. coli and Pseudomonas aeruginosa respectively. This isolate 
was incapable of inhibiting the other indicator bacteria. The other isolates have zones of inhibition ranging 
between 1 to 4 mm. Characterisation of the microbial metabolic product for antimicrobial agents reveals that 
lactic acid may be responsible for the inhibition of the indicator organisms.