Heat exchanger (HX) fouling is one of the main reason for heat recovery loss of efficiency and fouling detection can help to schedule maintenance operation and to optimize resource consumption. This works presents a patented fouling detection probe (FDP) based on the measurement of the related induced thermal resistance thanks to an electrically heated resistance temperature device. The main features of the device are presented, as well as the measurement protocol. A 1D device model is proposed to handle the corresponding use conditions and limitations. An example of a fouling situation from the food industry is described and the related potential FDP use is discussed. The thermal resistances (convection and fouling) measured with the FDP are consistent with both the 1D-model prediction and the literature data which is the first validation step of the FDP concept. Future works will then focus on a 2D-model development to take into account the 2D heat flux and the related experimental validation with well-known fluids.