Environmental monitoring of microbiological contamination in raw cow milk from dairy farms in Western Turkey.

This study evaluated the microbiological quality of raw cow milk from commercial dairy farms in western Turkey over a 3-year period (2023-2025) as part of an environmental monitoring framework. A total of 1800 samples were collected from mechanized farms in the major milk-producing districts of İzmir and analyzed for total colony count (TCC), somatic cell count (SCC), coliforms, Escherichia coli, Staphylococcus aureus, and Salmonella spp. A considerable proportion of samples exceeded regulatory limits, with 64% (1152/1800) and 22% (396/1800) non-compliance for TCC and SCC, respectively. Coliforms and E. coli were detected in 69% (1242/1800) and 52% (936/1800) of samples, while S. aureus was identified in 15%; Salmonella sp. was not detected. Seasonal differences were evaluated using the Kruskal-Wallis test (p < 0.05). Significant seasonal variation was observed for most parameters: SCC peaked in summer, coliforms and E. coli in spring, and S. aureus in winter, whereas TCC showed no significant seasonal trend. The observed microbial patterns indicate contamination pathways influenced by environmental conditions and farm-level hygiene practices. These findings suggest that microbiological indicators in raw milk may provide useful information on hygiene conditions and environmental influences within dairy production systems. Overall, the results highlight persistent hygiene challenges and emphasize the importance of continuous monitoring for environmental risk assessment and improved farm management. This study provides a large-scale 3-year evaluation of microbiological quality trends in raw milk and contributes valuable evidence for environmental monitoring and dairy hygiene management.