This study aimed to check the in vitro probiotic properties of eleven Lactobacillus fermentum strains previously isolated from fermented dairy products and infant faeces. These cultures were tested for their tolerance to different pH such as 2.0, 2.5, 3.0, 3.5 and 6.5, bile salt hydrolysis and cell surface hydrophobicity. All the strains were persistent at pH 3.5 for 3 h whereas only faecal origin isolates such as L. fermentum BIF-19, BIF-20, BIF-18 and MTCC 8711 had shown considerable growth at pH 2.5. The strains NCDC-400, MTCC 8711, BIF-18, BIF-19 and BIF-20 showed slight to intense precipitation zone of bile salt hydrolase activity by agar plate assay. The strain L. fermentum BIF-19 exhibited best preliminary probiotic properties was selected for the adhesion to Caco-2 cell lines, which shows similar adhesion to that observed for standard probiotic Lactobacillus rhamnosus GG.
Keywords: Acid tolerance; BSH; Caco-2; Cell adhesion; Lactobacillus fermentum; Probiotic.