Effect of mineral composition on thermoluminescence detection of irradiated seafood

Data from import control of irradiated seafood were collected from 300 batc hes of seafood. Thermoluminescence (TL) analysis, of the seafood, based on measurement of thermoluminescent minerals separated from intestinal tract, was carried out with a Riso TL-DA-10 instrument. As identified by X-ray dif fraction and SEM/EDS analysis, four main categories of minerals were extrac ted: tectosilicates; phyllosilicates, carbonates and sulphates. Detection o f irradiation was reliable when based on the TL of tectosilicate minerals, i.e. quartz and feldspar. Suitable minerals were found in most seafood: onl y about five percent of ail samples could not be successfully analysed beca use no minerals or only non-thermoluminescent clays or carbonates were foun d. False positive results were never obtained. A false negative decision re sults if analyses are based on hydrous clays or carbonates in the form of a ragonite. (C) 1998 Elsevier Science Ltd; All rights reserved.