Occurrence and characterization of microplastics in dry pet food: Investigating geographical variations between European and South American markets.

Pets are subject to latent toxicological hazard from microplastics (MPs) contamination in dry pet food (DPF). Very little is understood about the commercial and regional variables leading to the MP exposure by DPF intake. The goal of this study was to compare MP contamination in dog and cat DPF commercially available in Spain and Ecuador. The analysis relied on stereomicroscopy, scanning electron microscopy, and μFTIR spectrophotometry, which indicated a significant difference in MP abundance and composition. Ecuadorian items, especially those sold in bulk (loose), achieved concentrations of 12.33 ± 1.53 MPs/5 g, whereas Spanish samples maintained lower baselines (3.33-11.33 MPs/5 g). In unsealed Ecuadorian samples, Fourier transform infrared spectroscopy (μFTIR) revealed a broad polymeric profile that included polyethylene terephthalate (PET), polyethylene (PE), and polypropylene (PP) in combination with industrial indicators such as polytetrafluoroethylene (PTFE) and polydimethylsiloxane (PDMS) and the dangerous plasticiser benzyl butyl phthalate (BBP). According to morphological analysis, fibres represented 70-80% of the particles, and as many as 44% of them were classified in the potential translocatable 1-20 μm range. According to daily intake estimates, dogs in Ecuador had the greatest cumulative MP burden, consuming roughly 461 MPs/day as compared to 395 MPs/day in Spain. These results suggested that bulk commercialisation was a significant secondary vector for hazardous exposure, whereas industrial processing and raw materials (marine and agricultural) were the main contaminant sources. In conclusion, enhanced regulatory control of storage and packing processes shall be crucial to reduce chronic MP intake and potential endocrine disruption in pets.