Certified reference materials for food packaging specific migration tests: development, validation and modelling

Keywords:certified reference materials; diffusion; food contact materials; food packaging; laurolactam; migration modelling; nylon; specific migrationThis thesis compiles several research topics during a feasibility study for the certification of 6 reference materials for specific migration testing of food packaging materials. The overall results of the certification exercise, covering results for 3 certification parameters (initial concentration of migrants, specific migration value and diffusion coefficient) from 4 participating laboratories were evaluated. The development and validation of analytical methods for the nylon 12 monomer laurolactam was described. The new methods were applied during two studies. Alternative fatty food simulants for nylon 12 were evaluated, and nylon 12 films were subjected to two food simulants at either side simultaneously, in order to simulate their use as sausage casings. Mathematical models simulating both one- and two-sided migration were described and a way to estimate diffusion and partitioning coefficients of the migrants - including their confidence intervals - was introduced. Effects of gamma-irradiation on some certified reference material candidates were also investigated. Amounts of common polymer additives (Irganox 1076 and Irgafos 168) from polyolefins decreased with higher irradiation doses due to the degradation of these additives in the polymer, however, the overall migration did not significantly change. With rising irradiation doses, the sensory quality with respect to odour increased for polystyrene and decreased for the other polymers investigated.