THE DNA COMET ASSAY AS A RAPID SCREENING TECHNIQUE TO CONTROL IRRADIATED FOOD

The exposure of food to ionizing radiation is being progressively used in many countries to inactivate food pathogens, to eradicate pests, a nd to extend shelf-life, thereby contributing to a safer and more plen tiful food supply. To ensure free consumer choice, irradiated food wil l be labelled as such, and to enforce labelling, analytical methods to detect the irradiation treatment in the food product itself are desir able. In particular, there is a need for simple and rapid screening me thods for the control of irradiated food, The DNA comet assay offers g reat potential as a rapid tool to detect whether a wide variety of foo dstuffs have been radiation processed. In order to simplify the test, the agarose single-layer set-up has been chosen, using a neutral proto col. Interlaboratory blind trials have been successfully carried out w ith a number of food products, both of animal and plant origin. This p aper presents an overview of the hitherto obtained results and in addi tion the results of an intercomparison test with seeds, dried fruits a nd spices are described. In this intercomparison, an identification ra te of 95% was achieved, Thus, using this novel technique, an effective screening of radiation-induced DNA fragmentation is obtained. Since o ther food treatments also may cause DNA fragmentation, samples with fr agmented DNA suspected to have been irradiated should be analyzed by o ther validated methods for irradiated food, if such treatments which d amage DNA cannot be excluded.