USE OF RADIATION-INDUCED ALKANES AND ALKENES TO DETECT IRRADIATED FOOD CONTAINING LIPIDS

To detect irradiated foodstuffs, we used the Nawar relation between lipid structure and radiolysis compounds, such as alkanes and alkenes. We first applied this method to sunflower, olive and peanut oils. Alkanes and alkenes were analyzed by gas chromatography with a head-space system for desorption and concentration of the volatile compounds. The detection limit, obtained both by estimation of the chromatogram area and by a blind trial, is better than 0.15 kGy. The continuity of detection with storage time was also studied. We have compared these results with those obtained by thermolysis: the same method can be used to detect ionized vegetable oils, even if they have been heated. In a second step, we studied three possible commercial situations-the irradiation of avocado-pears, fresh pilchards and poultry meat. Although we can use this lipid method to identify irradiated avocado-pears (for doses above 0.5 kGy) and poultry meat, it is impossible to apply it to fresh pilchards because numerous volatile compounds are already present before irradiation.