Characterizing microplastic contamination in milk and cheese

Microplastic contamination in food products is an emerging issue due to its potential repercussions on food safety and human health. This study aimed to characterize microplastics in dairy product samples (n =28), including liquid milk, and fresh and ripened cheese, using Fourier-transform infrared microspectroscopy in attenuated total reflectance mode. Microplastics were found in 26 out of the 28 analyzed samples, with a total of 266 fragments belonging to 20 different polymers. Polyethylene terephthalate, polyethylene, and polypropylene were the most frequently detected polymers, found in 19, 15, and 12 samples, respectively. Microplastic concentrations varied significantly among products, with polyethylene exhibiting the highest average concentration (640.00 MP/kg), followed by polypropylene (516.67 MP/kg) and polyethylene terephthalate (357.89 MP/kg). The size of detected microplastics ranged from 24.00 to 4,817.00 μm, with average size of 243.74 μm. Most microplastics were < 100 μm (53.75%). Irregular fragments were the predominant shape (77.44%). Almost all detected microplastics were pigmented, with grey (68.42%), brown (15.04%), and black (9.77%) being the most common colors. These findings indicate that dairy products are a potential source of microplastics exposure for consumers. Further research is needed to assess contamination pathways along the production process and mitigate associated risks.