Abstract
The effect of Lactobacillus species isolated from probiotic drinks on the growth of Candida albicans and Escherichia coli was investigated. Two of the isolates, Lactobacillus casei Immunitas® and L. casei Shirota, are homofermentative organisms. They produced lactic acid that lowered the pH of the culture medium, resulting in a reduction in cell numbers of C. albicans and E. coli in mixed culture over a 24 h period. The third isolate, which was listed as L. reuteri and a hetrofermentative organism, produced the most DL-lactic acid compared to the other two isolates that produced L(+)-lactic acid in excess of D(−)-lactic acid and also lowered the cell numbers of C. albicans and E. coli in mixed culture over a 24 h period. Identification of each probiotic isolate was confirmed by an API 50 CHL strip test. Both homofermentative isolates were positively identified as L. casei, whereas the hetrofermentative isolate was identified as L. casei, a homofermentative organism – not L. reuteri, which is a hetrofermentative organism.