The present invention relates to a system for inhibiting the growth of pathogenic microorganisms, used in refrigerating appliances, air conditioners, and related apparatuses/equipment, using a sterilizing device (1) comprising an upper part (1A) and a lower part (1B), the upper part (1A) being provided with an electronic board (2) with ultraviolet LEDs (3) arranged in a duct (4), and the lower part (1B) having two parallel air circulation ducts (5), which are provided with a plurality of outlets (6), the device (1) being specially designed and located so that ultraviolet light directly impinges on the flow of cool air flowing inside the apparatus, causing the air circulating internally to have a sterilizing effect on the products stored inside a refrigerator or on the air produced by an air conditioner.