Dialkylketones in Paperboard Food Contact Materials—Method of Analysis in Fatty Foods and Comparative Migration into Liquid Simulants Versus Foodstuffs

Dialkyl diketene dimers are used as sizing agents in the manufacture of paper and board for food contact applications to increase wetting stability. Unbound residues can hydrolyze and decarboxylate into dialkylketones. These non-intentionally added substances (NIAS) have potential to migrate to fatty foods in contact with those packaging materials. In Germany, the Federal Institute for Risk Assessment (BfR) established a specific migration limit (SML) of 5 mg/kg for the transfer of these dialkylketones into foodstuffs. In order to investigate the differences between simulants and real foods, an analytical method was optimized for extraction and quantification of dialkylketones in edible oils and fatty foods by gas chromatography coupled with flame ionization detection (GC-FID), and additionally by gas chromatography with mass spectrometry (GC-MS), to confirm their identification and to quantify them in case of interferences. Dialkylketones are separated from the extracted fat by alkaline saponification of the triglycerides. Dialkylketones migration from paper-based food contact articles into organic solvents isooctane and dichloromethane, in olive and sunflower oils, and in fatty foods (croissants, Gouda, cheddar cheese, and salami was studied). As a result, it was found that the simulating tests, including the edible oil extraction tests, gave migration values that exceeded the SML largely, while the migration with the food samples were largely below the SML.