<p>The contamination of food systems by micro- and nanoplastics (MNPs) is an emerging threat to both environmental and human health. While the sources of MNPs, such as textiles, laundry effluents, and personal care products, are becoming increasingly well-documented, significant uncertainties remain regarding their identification, environmental transport, and biological effects. This review critically synthesizes the current knowledge on the entry, transport, and degradation pathways of MNPs in both terrestrial and aquatic systems, emphasizing the often-overlooked connections between the two. Importantly, the analysis highlights persistent gaps in knowledge, particularly the lack of standardized detection methods for nanoscale MNPs and insufficient long-term data on human health risks and dose-response relationships. By identifying these gaps and summarizing recent advances in detection technologies and mitigation strategies, this paper outlines key research priorities that need to be addressed to fill these knowledge voids. The insights gained from this review will promote interdisciplinary collaboration in developing policies that reflect the urgent need for improved MNP risk management and food safety governance.</p>