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 of trace elements from food contact packaging into four standard food simulants, acetic acid, ethanol, olive oil, deionised water. A sample of 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 radionuclides. The sample is then placed in the food simulant and the migration of the radionuclides is monitored by performing gamma-ray spectrometry on a sample of the simulant. Any radionuclides measured must be due entirely 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. This will highlight any differences between the standard simulants currently used and real foods. Since the method only involves irradiation of the packaging material, any food matrix can be studied.