Survey on the occurrence of photo-initiators and amine synergists in cartonboard packaging on the German market and their migration into the packaged foodstuffs.

In  a surveillance study from 2008 to 2011, in total 310 food products, predominately packed in cartonboard, were collected from the German market. First, the packaging materials were analysed for their content of six photo-initiators and five amine synergists by high-performance liquid chromatography with diode array detection (HPLC-DAD). If high amounts of these substances were detected, subsequently the foodstuffs were analysed by means of HPLC-MS or tandem MS, respectively. Benzophenone (BP) was detected in 49% of the packaging materials and was thus the most often determined compound, followed by 4-methylbenzophenone (MBP, 8%), 1-hydroxy-cyclohexylphenylketone (HCHPK, 7%) and methyl-o-benzoylbenzoate (MOBB, 5%). In total, 99 foodstuffs were analysed and in 20 cases one or more photo-initiators and/or amine synergists were detected in quantities above the legally acceptable limits in food. This resulted in several notifications in the European Rapid Alert System for Food and Feed (RASFF); the best known is MBP in breakfast cereals. Contamination of the foodstuff by the photo-initiators and/or amine synergists also occurred when it was in indirect contact with the printed packaging material and no adequate barrier material was used to prevent migration. The data also clearly demonstrate that polyethylene films are not suitable to inhibit migration. Storage of samples until the best before date showed that HCHPK, BP and MBP migrate very easily via the gas phase. In contrast, 4-phenylbenzophenone and 4,4'-bis(diethylamino)benzophenone migrated only very slowly or, respectively, not in quantifiable amounts into the foodstuffs. Differences in transfer rates for HCHPK, BP and MBP from several packagings into food and Tenax(®), respectively, lead to the assumption that both the food matrix as well as the extent of cross-linking of the printing ink during curing may have an influence on the level of migration.