The utility model relates to a multipurpose ultraviolet sterilizer, especially for air-conditioners and/or food processing having a housing member(s), preferably box-type, having an open top the allows passage of UV/UV-C emission and adjoining close and opaque side and bottom portions that conceals the UV/UV-C light out of sight. The housing member contains therein securely mounted germicidal ultraviolet (UV) lighting means or UV/UV-C lamp fixture with lamp(s) effecting UV-C pathogenic sterilization or disinfection of sterilizable ventilating/returning air or food item, and UV/UV-C light-reflecting means or acrylic mirror preferably disposed rearwardly of the UV lighting means, which intensifies and unilaterally and concentratedly directs the UV/UV-C light/radiation reflected thereon towards being emitted through the housing members open top portion thereby effecting an immensely enhanced and strengthened UVGI and UV-C pathogenic sterilization or disinfection process. A mounting means is provided thereto in a manner that when it is mountably attached to a fixture or wall, the housing member is securely mounted in a such a strategic position that puts the element or item to be irradiatively sterilized within the effective range of the radiated and reflected UV/UV-C light/radiation.
