This study was conducted to determine the microbiological safety of informally marketed raw cow milk across the milk supply chain in eastern Ethiopia. A total of 360 pooled raw cow milk samples (each with a volume of 450 mL) were collected from the udders and milk handling equipment of producers in rural areas of Babile district; from the equipment of collectors/transporters in Harar and Dire Dawa towns as well as from the equipment of vendors and consumer in Babile, Harar and Dire Dawa towns during February 2014 to January 2015. The raw milk samples were subjected to laboratory analyses to investigate the Escherichia coli (E.coli) and Staphylococcus aureus (S. aureus) counts as well as the prevalence of Salmonella species in the laboratory to determine the microbiological safety of the raw cow milk in the study area. The mean E. coli and S. aureus counts for milk samples collected directly from the udders were 3.33±0.11 and 3.09±0.12 log10 cfu mL-1, respectively. The values for samples collected from the equipment of producers upon arrival at their selling points were 4.46±0.11 and 4.03± 0.11log10 cfu mL-1 for E. coli and S.aureus, respectively. Mean E. coli and S.aureus counts for samples collected from the equipment of collectors/transporters upon arrival at their selling points were 5.54±0.06 and 5.04±0.0711 log10 cfu mL-1, respectively. The values for samples collected from the equipment of vendors were 6.30±0.06 and 5.69±0.07 log10 cfu mL-1 for E. coli and S. aureus, respectively. The mean count for raw milk sampled from the equipment of consumers were 6.32±0.06 and 5.75±0.07 log10 cfu mL-1 for E. coli and S. aureus, respectively. No Salmonella species was detected in the milk samples collected from the udder of milking cows; however, it was detected in 13.89, 18.06, 25.0 and 26.85% of raw milk samples collected from the equipment of producers, collectors/transporters, vendors and consumers, respectively. Generally, this finding indicated that raw cow milk samples collected from all milk sources were highly contaminated with E. coli and S.aureus, with counts exceeding the respective acceptable limits. Moreover, some raw milk samples obtained from the equipment of producers, collectors/transporters, vendors and consumers possessed detectable levels of Salmonella species. This suggests the need for implementing good hygiene practices and effective monitoring system from the point of production through the delivery chain to consumers as the presence of these pathogenic bacteria above the acceptable limit may pose a public health hazard to consumers. Keywords: Dairy production system, herd size group, location, milk source, season

Keywords: Microbiological Safety of Raw Cow Milk across the Milk Supply Chain in Eastern Ethiopia