Risk assessment of migrants released from multilayer packaging materials: Direct immersion-solid-phase microextraction coupled to gas chromatography-mass spectrometry

Milk is commonly contained in plastic multilayer pouches or cartons. Substances in these food packaging materials, such as additives, processing aids, degradation products, and residues may migrate into the milk, thereby causing contamination and human health risks. The migration of substances from six plastic multilayer pouches and five multilayer cartons that are commonly used as milk packaging materials into a model food (50 % ethanol) was studied. A direct immersion -solid phase microextraction-gas chromatography mass spectrometry (DI-SPME-GC-MS) method was optimized for the identification and quantification of the migrants. The optimal conditions were determined to be 60 min extraction time, 75 °C extraction temperature, and 1000 rpm stirring rate. Using this method, 36 compounds were found to have migrated into the milk, including several additives (such as bis(2-ethylhexyl) phthalate, acetyl tributyl citrate and erucamide), several degradation products (such as 2,4-di-tert-butylphenol and 7,9-di-tert-butyl-1-oxaspiro(4,5)deca-6,9-diene-2,8-dione), an initiator residue, and some solvents. A risk assessment was then conducted, and it was found that the exposure of certain substances from six plastic multilayer pouches into 50 % ethanol might pose potential human health risk. Our study showed that DI-SPME-GC-MS is a fast and efficient migration detection method, and our findings provide an important reference for the risk assessment of the potential migration of toxic substances from multilayer packaging materials into milk.