Abstract
Micro and nano-plastics (MNPs) have become a significant contamination concern. In agriculture, MNPs contaminate edible plants through different environmental pathways, threatening food safety and human health. The efficacy of commonly used post-harvest cleaning methods for mitigating this exposure remains largely unexplored. This study assessed the removal of microplastics (42µm polystyrene and 6µm polymethyl methacrylate) using in-situ confocal Raman spectroscopy, and nanoplastics (61nm polystyrene) using a novel dual-detectable nanoplastic tracer for both confocal Surface-Enhanced Raman Spectroscopy (SERS) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analysis. Our results reveal that while tap water washing effectively removed 42µm polystyrene MPs (Removal efficacy (RE) = 93.6 ± 3.6%), its performance significantly declined for 61nm polystyrene NPs (RE = 16.5 ± 0.6%). Detergent-based washing proved most effective for 6µm polymethyl methacrylate MPs (up to RE = 73.8 ± 0.9%), and sonication emerged as the most promising method for NP removal (RE = 59.8 ± 0.6%). By integrating high-resolution Raman and SERS imaging with ICP-MS quantification, this work offers a novel framework for evaluating fresh produce plastic contamination. Our findings highlight the urgent need to develop more effective post-harvest practices to limit dietary exposure to plastic particles.
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•Evaluated cleaning methods for removing micro-nano plastics (MNPs) from leaves.•Used an in-situ, non-destructive method to monitor MNPs on fresh produce.•None of the tested cleaning methods fully removed MNPs from produce surfaces.
