Tea polyphenols increase nanoplastic release from plastic cups but mitigate potential detrimental effects during simulated tea drinking

Abstract

The presence of micro- and nanoplastics (MNPs) in daily life raises increasing concerns about their potential health and environmental impacts. However, how food components influence MNP release from packaging materials and the resulting exposure risks remain poorly understood. Here, we investigated the effect of the primary tea polyphenol, epigallocatechin gallate (EGCG), on MNP release from polystyrene cups during a simulated tea-drinking process involving thermal treatments. A surface-enhanced Raman scattering sensor was developed to quantify released plastic particles in situ using EGCG-based luminescent metal–phenolic network labeling. The released particles were identified primarily as nanoplastics, and the presence of EGCG significantly (P < 0.05) increased MNP release, particularly during microwave heating and most prominently upon repeated cup use. Interestingly, EGCG increased the MTT response of differentiated Caco-2 cells exposed to released NPs in a dose-dependent manner, suggesting a potential mitigation of NP-associated cytotoxicity under the tested in vitro conditions. This study provides new insight into the dynamic interactions between food components and plastic packaging during realistic consumption scenarios, revealing an overlooked pathway influencing human exposure to nanoplastics. The findings expand the current understanding of contaminant release mechanisms at the food–environment interface and inform future strategies for exposure mitigation and sustainable material design to ensure food safety and protect environmental and public health.