Unexpectedly high occurrence of Escherichia coli and Staphylococcus aureus isolates from raw milk in Ilam, Western Iran

Raw milk contains diverse nutritional components that provide a suitable medium for spoilage and the growth of potentially pathogenic microorganisms. Unpasteurized milk consumption by a large number of people can threaten health and increase public concerns. In this study, sixty-two raw cow’s milk samples were collected from the dairy farms of Ilam, Western Iran. All samples were collected in sterilized containers and were transferred via ice boxes to the laboratory. Isolates were then identified by standard methods. Totally, 88.7% (n=55) of samples were contaminated. Our study also showed that Escherichia coli had a high prevalence among isolates (43: 69.4%), while Klebsiella pneumoniae and Klebsiella planticola showed the lowest prevalence (1: 1.6%). Staphylococcus aureus was also detected in 17.7% (n=11) of samples. The raw milk microbial contamination is complex. Some of the microorganisms threaten public health via different traits, therefore it is recommended that raw milk consumption should be avoided.