Different counts in MacConkey Agar

david.lawton1 david.lawton1 at ntlworld.com
Thu Jun 1 13:02:13 EST 2000


"Lynn" <kees.lyn at xtra.co.nz> wrote in message
news:39364780.F9C at xtra.co.nz...
> lamb wrote:
>  We use TSA or R2A for total counts, Cled for coliforms. 0.1 ml. per
> plate.
> >
> > Loes
>
>
> R2A was on my list, What is Cled? We currently do a lot of VRBA plates
> for coliforms but I was going to try a broth for MPN on the water
> samples, esp ones with low counts.
> Cheers Lynn

CLED - Cystine Lactose Electrolyte Deficient
It's probably more commonly used for urines.
IMHO 0.1ml wouldn't give a sufficient sample size for this type of test.
Counts from bore holes could well (no pun intended) be 0 in 100 ml
For E. coli & Coliforms we use membrane filtration and membrane lauryl
sulphate broth.
For total counts yeast extract agar at 37 & 22C

If you are going to do MPN we used to use minerals modified glutamate medium

Dave







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