THE VALIDATION OF A METHOD FOR DETERMINING THE MIGRATION OF TRACE-ELEMENTS FROM FOOD-PACKAGING MATERIALS INTO FOOD

A new radiotracer method has been developed to measure the migration o f trace elements from food contact packaging into four standard food s imulants, acetic acid, ethanol, olive oil, deionised water. A sample o f material is irradiated in a thermal neutron flux of 10(16) n.m(-2).s (-1) to activate the trace elements and produce a range of radionuclid es. The sample is then placed in the food simulant and the migration o f the radionuclides is monitored by performing gamma-ray spectrometry on a sample of the simulant. Any radionuclides measured must be due en tirely to the migration of the elements present in the plastic, since the simulant itself is not radioactive. Preliminary studies have shown that detection limits of around 0.2 mu g.dm(-2) (0.002 mg/kg) can be achieved for antimony in a sample of polyethylene terephthalate. This method can now been extended to measure migration into real foods. Thi s will highlight any differences between the standard simulants curren tly used and real foods. Since the method only involves irradiation of the packaging material, any food matrix can be studied.