Safety assessment of polypropylene self-heating food container: The release of microplastics and volatile organic compounds

The safety assessment of food-contact plastic products is crucial for protecting consumers from potential harmful chemical contaminants. This study investigated novel contaminants and substances of concern in self-heating food containers, focusing on the release of microplastics (MPs) and the migration of volatile organic compounds (VOCs). Using micro-Raman spectroscopy, we simulated actual self-heating condition to determine the abundance, size, and size distribution of released MPs. Results showed MPs abundance ranging from 1.7 × 10⁶ to 3.4 × 10⁶ particles/L, with an average of 2.4 × 10⁶ particles/L, where over 98 % of particles were smaller than 20 µm. For VOCs migration, we employed direct immersion solid-phase micro-extraction coupled with comprehensive two-dimensional gas chromatograph-tandem quadrupole-time-of-flight mass spectrometry (DI-SPME-GC×GC-QTOF-MS) under three migration conditions. We identified 41 VOCs, including saturated hydrocarbons, fatty acyls, organoxygen compounds, unsaturated hydrocarbons, benzene derivatives, and phenol ethers. Risk substances such as Dibutyl phthalate, Benzophenone, and 4-Methylbenzophenone were detected in three samples. Semi-quantitative analysis and toxicity classification revealed that the maximum migration of all analytes remained below corresponding limit values, indicating a generally low risk to consumers.