Study On Detection Analysis Methods For Irradiated Foods By Thermoluminescence

Food irradiation is a food processing technology which has a number of important attributes.It canimprove the safety and quality. The ability to analytically identify irradiated food complementary tocertification helps to enhance consumers confidence. It makes it possible to check compliance withexisting regulations (e.g. enforcement of labelling, control of prohibition) and to facilitate internationalfood trade. The thermoluminescence analysis method for irradiated foods is the best method in thosedetection methods. TL method for the detection of irradiation treatment of food by analysis ofcontaminating silicate minerals. Silicate minerals contaminating foodstuffs store energy by chargetrapping processes as a result of exposure to ionizing radiation. Releasing such energy, by heating ofisolated silicate minerals, gives rise to measure TL glow curves. Silicate minerals are therefore isolatedfrom the foods, mostly by a density separation step. A first glow of the separated mineral extracts isrecorded. Since various amounts and/or types of minerals exhibit very variable integrated TL intensitiesafter irradiation, a second TL glow of the same sample after exposure to a fixed dose of radiation isnecessary to normalize the TL response.The TL glow ratio, thus obtained, is used to indicate radiationtreatment of the food, since the population of irradiated samples on principle yields higher TL glowratios than that of unirradiated samples. Glow shape parameters offer additional evidence for identifyingirradiated foods.In order to found a integrated and perfect detection methods,we adoptes physical and chemistrialmethods to detect large number of foods samples between irradiated and non-irradiated products.Andestablished TL Reader detection method for irradiation food. The method includes the preparation ofdifferent food samples, and first TL indensity measurement, and the second TL indensily measurementand normalization.In the methods of preparation samples, it includes these different four types samples: spice anddehydrated vegetables, the fruits and fresh vegetables,the food containing fat from which silicateminerals can be isolated, and the food containing silicate minerals which can be dissolved.We studied the TL indensity measurement, and we normalize the parameters of TL readerapparatus.The preheating temperature was 50℃; the maximum temperature was 500℃at a heatingrate of 6℃/s;the blanching temperature was 600℃and data point was 1-250;and 100℃-500℃; andintegral range was between100℃and 500℃.For those irradiated sample by low dose.the fixed dosewas 0.5 kGy; and for those irradiated sample by high dose, the fixed dose was 1.0 kGy. For thoseirradiated sample by low dose, the fixed thresholds to the TL glow ratio was 0.07 and 0.1;detecting thesample as irradiated at a value higher than 0.1and unirradiated at a value lower than 0.07, whereassamples with TL glow ratios between 0.07and 0.1were considered as in doubt. For those irradiatedsample by high dose, the fixed thresholds to the TL glow ratio was 0.1;detecting the sample asirradiated at a value equil or higher than 0.1and unirradiated at a value lower0.1. We also studied various effect factors. The detection method for irradiated food depend on types ofsample, method of isolate mineral, organic constituents, the weight of mineral, the size of mineral,irradition doses and the types of radial. The result was certain the optimization condition: the size ofmineral is 3-Spin,the mineral weight is 5.0±0.1 mg.The TL Reader Detection Method is applicable to a large variety of foodstuffs. The method is aintegral and perfect method for the detection of irradiated food.