Abstract: An improved method for determining a viable microbial cell count in a sample wherein the method comprises the steps of filtering a microbe-containing sample solution through a hydrophilic membrane, thereby trapping viable microbes thereon, then spraying an extracting reagent onto the viable microbes trapped on the membrane, thereby lysing the microbial cells. The lysed cells are then sprayed with a solution of luciferin-luciferase reagent, thereby inducing a luminesent signal. The signal is then quantified using a CCD-based device. The improvement comprises the use of a volatile alcohol extracting reagent for lysing the viable microbes, then evaporating the alcohol prior to spraying the luciferin-luciferase solution, leaving a concentrated ATP,containing solution for enhanced luminescent detection.