coliforms testing

[Dave]

"Des O'Connor" <des at micro-search.com> wrote in message
news:N5rQ8.9437$VP6.709993 at stones...
> Your using VRBA right ?  NOT RVBA
>
> After 24 hours  Pseudomonas species should produce much smaller colonies
> wiht no halo typical of Coliforms.
>
> You could pick suspect colonies off and do an  Oxidase test  directly. As
> far as I I know allColiforms are OX -ve while the Pseudomonas species you
> mention ar eofcourse Ox postive.
>
> A superior alternative would be to use one of the chromogenic  substrate
> based agars.
>
> Best
> Des
You just beat my suggestion.
Merck produce a chromogenic agar for coliforms called Chromocult.
E. coli produce blue colonies and coliforms red and will be easily
distinguishable from Pseudomonads

Dave