Probiotic properties of lactic acid bacteria isolated from fermented sap of palm tree (Elaeis guineensis)

The commonly used probiotics bacteria are lactic acid bacteria (LAB) from gastro intestinal tract. However, other LAB from exogenous origin having similar functional properties may also confer health benefit to the host. Palm wine has been described as a rich source of LAB. But very few studies have investigated their probiotic potential. Twenty LAB were isolated from palm wine collected in the South West Region of Cameroon by pour plate method on MRS agar. These isolates were assessed in vitro for their potential to inhibit the growth of some foodborne pathogens, mainly Salmonella sp. and Escherichia coli using disc diffusion method. Acid and bile tolerance were evaluated by measuring the survival rate of LAB after incubation at pH range from 1.0 to 3.0 and various bile salt concentrations (0.15-0.30%). Only five isolates were selected based on their potential to inhibit food borne pathogens tested and their tolerance in acid and bile. They were identified using API kit 50 CHL BioMerieux as strains of Lactobacillus pentosus, Lactobacillus plantarum and Lactobacillus brevis. All these strains showed antimicrobial activity against strains of Salmonella sp. and E. coli with diameters of inhibition varying from 12 to 20 mm. Only L. pentosus and L. brevis1 tolerated pH 3.0 (acidic condition of interest) with survival rates of 55 and 69% respectively, while all survived in bile with survival rates above 60%.   Key words: Probiotics, antimicrobial activity, acid tolerance, bile tolerance.