Hi,
The actual type of agar to use on total counts is not that important.
It should be a rich medium, such as Reinforced Clostridial Agar,
supplemented with either blood or faecal extract. In addition to this
we also add vitamin K and the salt solution described by Holdeman and
Moore in the VPI manual.
Do not use BHI-blood agar or Schaedler agar, as these give lower
counts. So does Brucella Blood agar.
More important is the way you handle the samples.
Be aware of the following points:
- do not use platic vials and containers for transport
- never freeze a sample (unpredictable and unreproducible changes)
- do not work on the bench, but in an anaerobic chamber
- treat the samples as fresh as possible
- do not use a vortex or ultra-turrax to homogenize the samples
outside an anaerobic chamber (inside is OK)
- pre-reduce your dilution medium (physiological salt + 0.5 g/l
cystein.HCl at pH 6.7)
- do not dilute the samples outside an anaerobic chamber
Finally, working with (slaughtered ?) animals : when you kill an
animal the mucous layer will loosen and the intestinal contents will
mix. So use anaesthisized animals.
We have submitted a manuscript on the effects of different media and
methods on total counts and also have a lot of experience with animal
samples. Don't hesitate to ask any further !
Ralf Hartemink
Division Food Science
Food Microbiology Dept
Intestinal microbiology group
Wageningen Agricultural University
PO Box 8129
6700 EV Wageningen
The Netherlands
ralf.hartemink at micro.fdsci.wau.nl
On Thu, 22 Oct 1998 08:44:04 +0200, Tom Granli
<Tom.Granli at hre.hydro.com> wrote:
>I plan to do research on the normal microflora in gastro-intestinal
>tract (GIT) of various animals. One aspect is to determine (as good as
>possible) the number of total anaerobic bacteria (preferably vial) in
>various parts of the GIT.
>>In this regard I would appreciate suggestions for proper methods to use,
>both agar counts, chemical analyses or other methods. Your experiences
>of the suggested methods is also very welcome.
>>Regards,
>Tom Granli.
