Microplastics contamination of milk and milk products in Bangladesh: Characterization, dietary exposure, and risk assessment

Milk is a nutritionally complete food that provides essential proteins, lactose, vitamins, and minerals necessary for human growth and development. However, research on microplastic (MP) contamination in milk and dairy products is limited, and no studies have examined raw, branded, and processed types in Bangladesh. This study aimed to evaluate the characteristics of MPs, along with associated dietary exposure and polymeric risk, in raw milk (n= 17), branded milk (n= 12), and milk products (n= 12). MPs were isolated using hydrogen peroxide digestion and vacuum filtration. Particles retained on the filters were examined microscopically and categorized by size, color, and shape, while polymer types were identified using FTIR spectroscopy. The average MP concentrations were 93.39 ± 87.15, 156.06 ± 145.78, and 70.80 ± 78.09 particles per 100 mL in raw, branded, and processed milk, respectively. Transparent, fibrous MPs smaller than 250 μm predominated, with PTFE, PET, nylon 6, PE, and PDMS as dominant polymers. Children exhibited higher dietary exposure than adults. The polymer risk index indicated high, considerable, and moderate risks for raw, branded, and processed milk, respectively. These results highlight the urgent need for continuous monitoring, improved processing, and regulations to reduce MP contamination in Bangladesh’s milk supply chain. • First study on microplastics in raw, branded, and milk products in Bangladesh. • Branded milk sample had the most microplastic abundance • Children had the highest exposure to microplastics of the three types of samples. • Risk index (average): high in raw, considerable in branded, moderate in milk products. • Urgent need for monitoring and reducing plastic usage in the dairy supply chain.