Detection of irradiated prawns using 2-alkyl-cyclobutanones

The use of ionizing radiation for the preservation of food has been under investigation for many years but yet has to receive worldwide acceptance. Although irradiation can be carefully controlled, it is generally accepted that the development of tests for detection of irradiated food would enhance consumer confidence and might help to enforce labelling regulations. The alkylcyclobutanones are reported to be the only cyclic compounds formed as the products of the radiolysis of saturated triglycerides. The synthesis of 2-dodecylcyclobutanone (DCB) and 2-tetradecylcyclobutanone (TCB) has been carried out. Using irradiated chicken meat as the model for a fat-containing food, both cyclobutanones have been extracted with solvent and then identified by gas chromatography-mass spectrometry. DCB and TCB have been detected in chicken meat irradiated at doses well below 10 kGy and were not detectable in unirradiated chicken. Systematic studies have been undertaken to confirm the specificity of these compounds as markers for irradiation treatment. The presence of both DCB and TCB in other irradiated meats and irradiated liquid whole egg has been confirmed. The feasibility of applying the method to low- fat-containing foods, such as prawns, is now underway. Preliminary studies have shown that both DCB and TCB have been detected in prawns irradiated at doses likely to be used commercially. 3 refs. (author)