2.1. Viable microbial count
Total viable bacterial count was determined for each unit formulation purchased using the following procedure: One gram of the preparation was dispersed in an autoclaved sterilized phosphate buffer containing 0.5% Polysorbate 80 (preservative neutralizer) and then 10-fold serial dilutions were made under aseptic conditions. Pour plate technique was performed on a 1-ml aliquot taken from the appropriate dilution using soya bean casein digest (SBCD) agar. Solidified agar plates were incubated at 37 C for 48 h before developed colonies were counted. Yeasts were counted as described for bacteria but Sabouraud dextrose agar (SDA) was used. Molds were isolated on Sabouraud dextrose agar and results were considered positive if, after incubation at 25 C for 2 wk, fungal growth appeared on the inoculated plates. Certain bacteria can grow on SDA; thus the medium was supplemented with antibiotics (chloramphenicol and gentamycin) to inhibit bacterial growth. Colonies recovered were further confirmed as yeast by observing their resistance to antibiotics using the disc diffusion method.