Evaluation of Commercial Probiotics against Cronobacter Sakazakii

Abstract

Lactic cultures isolated from commercial probiotics were examined for antibiotic, antimicrobial and biofilm inhibition assays. LAB isolated from commercial probiotics has shown the antimicrobial activity against C. sakazakii strain. Culture isolated from yakult has shown maximum activity in both heat killed cell free supernatant and in untreated cell free supernatant. Isolate from Bifilac has shown activity in pH neutralized supernatant also along with heat treated and non treated CFS. LAB isolated from yakult have shown resistance against all the antibiotics, LAB isolates from different probiotics have shown resistance, susceptibility and intermediate results against different antibiotics. Biofilm inhibition activity of LAB against C. sakazakii was observed with Cell free supernatant of selected LAB isolates. Minimum inhibitory activity was measured and the minimum concentration which is responsible to inhibit the biofilm formation was found to be 50 μl. In co incubation assay the maximum biofilm inhibition was shown by untreated CFS and heat treated CFS where as minimum biofilm inhibition was shown by heat treated CFS. In post incubation assay untreated CFS have shown the maximum inhibition and then heat treated CFS. Minimum inhibition was shown by pH neutralized CFS. Biofilm inhibition was maximum during 12 hr of incubation. with increase in time the biofilm inhibition decreased. i.e. less inhibition was seen during 24 and 48 hr of incubation as compare to the 12th hr of inhibition which was maximum