Migration of chemical compounds from cardboard food contact materials into food: Development of a fast and reliable method to detect photoinitiators in dry foodstuffs

Food packaging, providing physical protection and extending the shelf life of dry foodstuffs, are becoming increasingly complex in their design and composition. The direct contact, and in many cases the indirect contact, between the food packaging and the food, yield the transfer of relative low molecular weight compounds such as photoinitiators, mineral oil hydrocarbons, phthalates… Photoinitiators are commonly used in the formulation of UV-cured inks for short drying times. However, the photo-initiators are not always completely utilized or removed after the printing process. Food packaging made of recycled materials form another problem for food contamination. Newspapers and other printed materials are recycled to make new food packaging. Unfortunately, the recycling process does not fully eliminate the photoinitiators. As a result, migration can still occur, even though the packaging itself has not been printed with UV-cured inks.
Since migration of contaminants into food may pose a threat for consumers, it has highlighted the need for occurrence data of these contaminants and thus fast and reliable confirmation methods should be developed.
For the determination of photoinitiators such a confirmation method was developed. First, the substances were extracted from the dry food using acetonitrile. Next, the extracts were purified and subsequently analysed for the presence of photoinitiators, using ultra high performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS). For the method, an in-house validation was executed, thereby evaluating the following performance characteristics: linearity, recovery, matrix effect, repeatability, reproducibility and sensitivity.