Cattle faeces are likely to be highly contaminated with other
coliforms and serotypes of E. coli other than O157:H7.
Environmental material was only inoculated with pure
cultures of E. coli O157:H7, thus, possibly eliminating any
competition effects during enrichment from other coliform
bacteria that may have been introduced through cattle faeces.
Previous studies, using the same enrichment media and PCR
primers for detection of E. coli O157:H7 in spiked bovine
faeces, reported sensitive pathogen detection down to initial
inoculum values of 1 cfu g±1 material (Hu et al. 1999). These
data suggest that enrichment conditions were appropriate,
enabling growth of low numbers of target E. coli O157:H7
population despite the potential presence of other competing
coliform bacteria that are likely to be high in cattle faeces.