Detection of irradiated plant foods by photo- and thermally-stimulated luminescence

Abstract

The aim of this work was to verify the applicability of the European Standard EN 13751, based on Photo-Stimulated Luminescence (PSL) and the European Standard EN 1788, based on Thermoluminescence (TL), for the detection of irradiation in plant food supplement (PFS) ingredients, nuts and fresh fruits with health benefits. In particular, in this work, herbal ingredients (Camellia sinensis, Ginkgo biloba, Glycine max, Silybum marianum, Vaccinium myrtillus), almonds, hazelnuts, peanuts, pistachios, walnuts and fresh blueberries, papaya and mango, were analyzed by both stimulated luminescence methods. To verify the reliability of the methods in detecting the treatment over time, the analyses were replicated after irradiation within the product shelf life. The PSL screening method allowed to correctly identify blueberries, nuts and raw materials of PFS but failed with dried herbal extracts, mango and papaya, due to their low content of silicates. To validate the procedure elaborated during the preliminary study, blind tests, involving several national laboratories of the official control, were organized. The tests confirmed the limits in detecting dried extracts, mango and papaya by PSL technique. TL method resulted suitable as a confirmatory method for all the matrices of the study.