AN INTERLABORATORY TRIAL ON THE IDENTIFICATION OF IRRADIATED SPICES, HERBS, AND SPICE-HERB MIXTURES BY THERMOLUMINESCENCE ANALYSIS

Thermoluminescence analysis was used in an interlaboratory study to de tect irradiation treatment of spices, herbs, and spice-herb mixtures i n the dose range used for the reduction of microbial counts. About 3 a nd 9 months after irradiation, 14 participating laboratories determine d the thermoluminescence of mineral contaminants that had been isolate d from coded samples, A total of 18 different products (6 spices, 6 he rbs, and 6 spice-herb mixtures) were examined, The method gave correct identifications as irradiated or nonirradiated in 99.1% of 317 sample s. Only 3 irradiated samples were not correctly identified, This resul t was achieved by integration of whole glow curves. By glow curve anal ysis, a temperature range could be determined in which differentiation between irradiated and nonirradiated samples was even better than on the basis of the total integral values.