From farm to fork: Microplastic contamination in the meat and dairy supply chain

Microplastics (MPs) are now widespread contaminants in both terrestrial and aquatic ecosystems, leading to increasing worries about food safety and public health. This review offers an in-depth evaluation of the prevalence, pathways, and risks associated with MPs in meat and dairy products, which are significant global sources of animal-based nutrition. Data from different countries shows a persistent presence of MP contamination in livestock tissues, poultry organs, processed meat products, raw milk, and commercial dairy items, with identified polymer types such as polyethylene, polypropylene, polystyrene, nylon, PET, and regenerated cellulose. MPs are primarily found in the form of fibers, fragments, films, and irregular particles, with sizes varying from less than 10 μm to several millimeters. Their concentrations can range from a few particles per gram in raw meat to over 30,000 MP/kg in processed products, and from several MPs per liter in raw milk to more than 1800 MP/kg in cheese. Contamination occurs at various points along the farm-to-fork continuum, encompassing ingestion via tainted feed and water, interaction with agricultural plastics, transfer from milking and processing apparatus, wear during cutting and grinding, and leaching from packaging materials. Recent toxicological findings indicate that MPs and their related chemical additives could lead to gastrointestinal inflammation, oxidative stress, endocrine disruption, immunomodulation, and microbiome dysbiosis, although the long-term health effects are still not fully comprehended. Inconsistencies in methodology related to sampling, particle extraction, and spectroscopic identification impede precise comparisons of exposure and assessments of risk. The review points out significant gaps in current studies and emphasizes the necessity for uniform analytical techniques, enhanced waste and plastic management, as well as sustainable processing and packaging approaches to reduce the entry of MPs into animal-derived foods.