5. Conclusions
The essential requirement of any agar media for the isolation of
bacteria is the ability to support the growth of the target organism, and
secondary to that is the ability to suppress the growth of non-target
organisms. Consequently, we conclude that due to the significant proportion
of STEC strains whose growth is inhibited on these media, including
strains of priority serogroups, that the agar media RBA-USDA, RBA-NT,
and CH STEC are unsuitable for application to the isolation of STEC from
beef as the sole isolation media. Nonetheless, RBA-USDA, RBA-NT, and
CH STEC might be applied to beef samples containing high levels of
background microflora, if paired with an agar media capable of
supporting the growth of a wide range of STEC, such as MAC, RBA
or VTEC agar.