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
