Abstract: An apparatus for inhibiting the growth of microbiological organisms in commercial icemakers and coolers by treatment of the air within the device evaporator air space. The apparatus includes a mechanical filtration device, a PCO device, and a UV light device. Air is drawn from the evaporator space, mixed with a small amount of ambient air from around the apparatus, and mechanically filtered to remove particulates. The filtered air is then passed through the PCO device that is activated by the UV light device, where it is treated by the ROS produced by the activated PCO device. A UV light further produces ROS to treat the filtered air stream, which is returned to the internal space of the commercial refrigeration device. Recirculation of the treated air increases residence time. The addition of a small amount of external air with the internal air allows for positive pressurization of the evaporator space.