The identification of irradiated crustaceans and evaluation of the dose by thermoluminescence: Intercomparison between two methods for extracting minerals

The thermoluminescence (TL) is one of the physical methods recommended by the European Committee for Standardization, for the identification of irradiated food from which silicate minerals can be extracted. The efficacy of the method strongly depends on the quantity and purity of the extracted minerals, and therefore on the extraction procedure. In this work we applied the TL for the identification of crustacean Nephrops norvegicus irradiated at 0.5−1.5−3.0 kGy, comparing two different procedures for extracting minerals: by means of a density gradient or with acid hydrolysis. The identification of the irradiation treatment was always achieved with both procedures, without any false positive. A dose reconstruction method was also set up and tested. A little preference should be given to the acid hydrolysis extraction procedure, that requires less quantity of food sample and reagents, as well as less time to be carried out, and gives a satisfactory reconstruction of dose.