medium for water bacteria

Enigl enigl at aol.com
Thu Apr 4 10:18:07 EST 1996


In article <4jukvp$6nq at kadri.ut.ee>, kisand at kadri.ut.ee (Veljo Kisand)
writes:

>Subject:	medium for water bacteria
>From:	kisand at kadri.ut.ee (Veljo Kisand)
>Date:	3 Apr 1996 19:53:29 GMT
>
>Hi!
>
>I would like to grow up as many as possible colonies from eutrophic lake
>water. Which medium should I use?
>
>thanx in advance
>
>Veljo Kisand
>
>

The "most" is subjective because it depends on your target type of
microorganisms.  For Heterotrophic Plate Counts of just the water, I
suggest:

R2A medium from DIFCO.  20-25 degrees C for 7-14 days inside a humidified
bag.  If you use "single cell isolation-dilution" method to recover the
most kinds of colonies you will reduce the competitive inhibition by the
most predominant species, but, you will  go through hundreds of plates, .
. . be warned ;-).  If you just want a "total" (no such thing) Plate Count
use hot agar pour plate or spread plate methods.

Different media are used depending on what you want.  What is sampled
(only water? or sediment?, vegetation? )  and what you  want (
psychrotrophs?  methanogens? heat resistant spore formers?  anaerobes?
thermophiles?.  Each type of organism is adapted to its own environment
and uses a different medium, temperature, etc.

  


Davin C. Enigl, MS, MEAS
Senior Microbiologist, Consultant
HACCP Validations-sm
Hazard Analysis and Critical Control Point Validations
For the Food, Cosmetic and Pharmaceutical Industry
April 3, 1996
9:41 pm



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