ํThe supernatant is discarded and the pellets in each of the centrifuge tubes are resuspended in 5 mL of normal saline. The two bacterial suspension of the same bacteria are added aseptically to a sterile universal bottle, thereby achieving a total volume of 10 mL. The optical density is measured at a wavelength of 500 nm using a CE 272 Linear Readout Ultraviolet Spectrophotometer, and serial dilution are carried out to optical density in the range of 0.5-0.1. The actual values are noted and the cell-forming units are calculated using are calculated using equation from previously provided viability graphs for the particular bacterial species. The bacterial solution is diluted accordingly to obtain a concentration of 5x105 CFU/mL.