RUMEN CONTENTS AS A RESERVOIR OF ENTEROHEMORRHAGIC ESCHERICHIA-COLI

We investigated the role of the rumen fermentation as a barrier to the foodborne pathogen, Escheiichia coli O157:H7. Strains of E. coli, inc luding several isolates of O157:H7, grew poorly in media which simulat ed the ruminal environment of a well-fed animal. Strains of E. coil O1 57:H7 did not display a superior tolerance to ruminal conditions which may facilitate their colonization of the bovine digestive tract. Unre stricted growth of E. coli was observed in rumen fluid collected from fasted cattle. Growth was inhibited by rumen fluid collected from well -fed animals. Well-fed animals appear less likely to become reservoirs for pathogenic E. coli. These results have implications for cattle sl aughter practices and epidemiological studies of E. coli O157:H7.