Detection of irradiated spices by different physical techniques.

We used thermoluminescence, electron spin resonance, and viscosimetric measurements to establish whether or not a spice had been irradiated. Thermoluminescence, using the 1788 EN official protocol with an alternative method for the extraction of mineral impurities, led to proof of irradiation or proof of no treatment. Electron spin resonance led to different spectrum shapes depending on the chemical composition of the spices; ESR could only be used as proof of irradiation up to several weeks after irradiation, and only for some spices. Viscosimetric measurements carried out on spice suspensions led to a presumption of treatment (or of no treatment) and possibly to proof of irradiation.