Polyethylene Packaging as a Source of Microplastics: Current Knowledge and Future Directions on Food Contamination

Polyethylene (PE) is the most widely produced plastic globally. It is extensively used as packaging in both the food and pharmaceutical industries. Its use can result in the formation of emerging contaminants-microplastics (MPs). This review summarizes current knowledge on PE and PE-derived microplastics (PE-MPs) and highlights existing gaps. It discusses the factors influencing PE degradation, with particular emphasis on interactions with packaged contents and food products. The role of PE-MPs as vectors for environmental contaminants is also examined, focusing on their adsorption and desorption behavior. Finally, we explore the toxicity and bioaccessibility of PE-MPs. Our findings indicate that pH, temperature, and exposure time are the most significant factors driving PE degradation. However, comparative studies examining a broad spectrum of parameter values remain scarce. The process of PE-MP generation remains largely unexplored. Adsorption mechanisms on PE-MPs are well documented in the literature. In contrast, desorption has received significantly less scientific attention, and its relevance to human exposure is still unclear. Numerous studies have suggested potential links between human exposure to PE-MPs and the development of non-communicable diseases, including cardiovascular and neurodegenerative disorders. Nevertheless, no studies have yet examined the bioavailability of PE-MPs. Similarly, the dose-response relationship between PE and MP exposure and toxicological outcomes in humans remains unclear. As a result, it is currently not possible to establish safety thresholds for PE-MP contamination in food products. This review offers a novel polymer-specific approach to MPs research and outlines specific recommendations for future studies.