DETECTION OF GAMMA-IRRADIATED RAW-MILK CAMEMBERT CHEESES BY CAPILLARYGAS-CHROMATOGRAPHIC ANALYSIS OF VOLATILE HYDROCARBONS

A method to detect the irradiation of raw-milk Camembert cheeses by ga s chromatographic analysis of radio-induced volatile hydrocarbons, for med by radiolysis of myristic, palmitic and stearic acids, is proposed . The presence, in the sample, of tridecane, 1-dodecene, 1-tetradecene and 1-hexadecane, in association with an increase in levels of pentad ecane and heptadecane, can be considered an indication of irradiation. Moreover, the quantity of radio-induced volatile hydrocarbons, formed from the same fatty acid precursor, is proportional to the fatty acid composition in the sample and the 1-alkene/alkane ratio remains const ant (similar to 13) and independent of the fatty acid precursor. In sp ite of the hydrocarbon stability during ripening and storage and the g ood linear correlation between the hydrocarbon concentration and the i rradiation dose (up to 397 kGy), the determination of the latter is ap proximate because of the experimental error (+/-20%) and the possible fluctuations of certain parameters of the ionizing treatment (e.g. tem perature and dose rate).