Identification of gamma ray irradiated wheat by electron spin resonance, DNA comet assay and germination test

In several countries, there has been an increase in the use of radiation for food processing thus improving the quality and sanitary conditions, inhibiting pathogenic microorganisms, delaying the natural aging process and so extending product lifetime. The need to develop analytical methods to detect these irradiated products is also increasing. The goal of this research was to identify wheat irradiated using three different techniques: Electron spin resonance, DNA comet assay and germination test, for comparison. Wheat variety IAC 289 and husked wheat variety IAC 355 was from Instituto Agronomico de Campinas. Grains were irradiated with a gamma 60Co source (Gammacell 220 GC) in the Centro de Energia Nuclear na Agricultura and in the Instituto de Pesquisas Energeticas e Nucleares. Dose rate used were 1.6 kGy/h and 5.8 kGy/h. Applied doses were 0.0 kGy ; 0.10 kGy ; 0.25 kGy ; 0.50 kGy ; 0.75 kGy ; 1.0 kGy and 2.0 kGy. After irradiation, grains were analyzed over a 6 month period. It is possible to use E8R to identify irradiated husked wheat until 3 weeks after the date of irradiation. Comet assay was a qualitative test that we used to identify irradiated wheat at least 6 months after storage. The germination test make possible the identification and the better criteria was the shoot length. (author)