Current knowledge and challenges in the characterization of microplastics and their contamination sources in animal-based foods.

Microplastics are emerging contaminants in the food chain, raising concerns about human dietary exposure. This review critically assesses their occurrence in animal-based foods, including milk and dairy products, meat, fish, honey, and eggs, focusing on analytical approaches used for detection, identification, and quantification, as well as on reported contamination levels. Evidence indicates widespread contamination in animal-based foods, although concentrations, polymer types, particle size, and morphology vary considerably depending on food matrix composition, environmental exposure, processing conditions, and packaging. Spectroscopic techniques, particularly Fourier Transform Infrared and Raman spectroscopy, represent the most widely applied methods for polymer identification; however, significant methodological heterogeneity limits inter-study comparability and data harmonization. Reported concentrations span several orders of magnitude due to analytical variability and matrix effects. Processing and packaging are key contamination sources. Despite increasing evidence, regulatory frameworks remain limited and lack harmonized standards, highlighting the need for methodological standardization, improved exposure assessment, and mitigation strategies.