Antimicrobial activity was evaluated by measuring the zone of inhibition against the test microorganisms. The growth inhibition level exhibited by a selected microorganism for every different biocide tested can be quantitatively calculated by measuring the diameter of the inhibition zone, that is, the clear halo around the disc. Thus, K–B tests were carried at room temperature for 48 h, after which an average inhibition diameter was calculated for every combination of microorganism and biocide tested.