Comparison of pulsed and CW ultraviolet light sources to inactivate bacterial spores on surfaces

The University of Missouri-Columbia is optimizing photosensitized UV processes for the decontamination of surfaces. The biological inactivation results obtained with high-power pulsed xenon flashlamps are compared to those of a continuous-wave medium-pressure mercury-argon lamp. The inactivation mechanisms associated with pulsed and continuous-wave multispectral light sources, which are used synergistically with a hydrogen peroxide photosensitizer, are discussed. Typically, the process yields more than six logs reduction of Bacillus subtilis spores on various surfaces.