A system for the treatment of fats, such as those that can be carried preferably in fumes or fumes products, in a kitchen or food industry installation, and which can be linked to the extraction and/or conduction installation of said fumes, comprising at least a source (4) of UV radiation, which can be UVA and preferably of a wavelength of 315 to 380 nm, preferably of a laser type, pulsed light or LED (for example a LED of gallium nitride). Sources are preferably placed on the wall or ceiling of the flue, so that they are accessible from the outside.