This document specifies a method for the detection of foodstuff containing cellulose which have been treated with ionizing radiation, by analysing the electron spin resonance (ESR) spectrum, also called electron paramagnetic resonance (EPR) spectrum, of the foodstuff. Interlaboratory studies have been successfully carried out with pistachio nut shells, paprika powder and fresh strawberries. However, it has been shown that chemical bleaching of nuts in shells can lead to comparable signals.
