Food irradiation aims to eliminate biohazards such as pathogens, microbes, fungi, etc. identification of irradiated food and dose assessment ensures its safe use. Hazelnut is the most universal widespread nut and can be found as a whole fruit or as an ingredient in many food types. Electron paramagnetic resonance (EPR) was used to identify irradiated hazelnut and to assess radiation doses delivered to it using fractions of its kernel and shells. In this paper, parameters affecting the proper detection and evaluation of irradiated hazelnut kernels and shells are studied and analyzed including the response to Cs-137 gamma rays, effect of the change in microwave power and modulation amplitude values during EPR spectra acquisition. Stability study of the radiation-induced radicals suggests that it is better to perform EPR measurements for irradiated hazelnut during the first month following irradiation.