Practical experience in the use of mathematical models to predict migration of additives from food-contact polymers

To reduce the amount of compliance-specific migration testing for food-contact polymers, the use of migration modelling has been evaluated. The paper describes experimental work carried out on a range of plastics and compares measured migrations against predictions obtained using mathematical models. A large number of experimental migration data have been obtained and used to evaluate a Fickian-based migration model in the prediction of specific migration of additives into olive oil. All tests were conducted using olive oil, representing the most severe case for fatty foods with test conditions including 2h at 121 degrees C, 6h at 70 degrees C, 2h at 70 degrees C, 2h at 60 degrees C and 10 days at 40 degrees C, representing short-term exposures at high temperatures and room temperature storage. Predicted migrations were calculated by inputting the measured initial concentration of additive in the polymers (Cp,0) into the equations together with known variables such as additive molecular weight, temperature and exposure time. The results indicate the Piringer migration model, using the 'exact' calculations of the Migratest Lite program, predicted migrations into olive oil that were close to or in excess of the experimental results and gave an overestimation for > 95% of the migrations generated here.