Risk of Escherichia coli O157:H7 transmission linked to the consumption of raw milk

E. coli O157:H7 is associated with life threatening diseases such as hemorrhagic colitis (HC), hemolytic uremic syndrome (HUS) and thrombotic thrombocytopenic purpura (TTP). Raw milk is considered a high risk food as it is highly nutritious and serves as an ideal medium for bacterial growth. The aim of this study was to investigate the prevalence of E. coli O157:H7 in raw cow, goat and buffalo milk samples. MPN-PCR method targeting the major virulence rfbE gene and fliCH7 gene of E. coli O157:H7 was used. Total of 177 raw milk samples were collected from local dairy farms in the state of Selangor, Malaysia. The highest prevalence of E. coli O157:H7 was found in raw cow milk (18.75%). E. coli O157:H7 was detected in 7.32% and 3.57% of raw goat and buffalo milk, respectively. The estimated quantity of E. coli O157:H7 in raw cow, goat and buffalo milk ranged from 3 MPN/g to 73 MPN/g. Raw cow milk samples showed the highest quantity of E. coli O157:H7 (MPN value of 73 MPN/g) while raw goat milk samples had the lowest quantity of 36 MPN/g. Results of this research provide useful information on biosafety of E. coli O157:H7 in raw milk marketed in Malaysia.