agars

Dilworth bactitech at hortonsbay.com
Thu Jul 5 23:21:21 EST 2001


I'm sure your method was better, but our hospital was too cheap to buy
different flasks and that's what we had.  The tech who got stuck making
most of the media (because no one else wanted to - I think he used it as
an escape mechanism, but that's another story entirely :-)) had his own
way of doing things and 98% of the time everything worked.  

Your way, of course, is much more scientific :-).

Judy Dilworth, M.T. (ASCP)
Microbiology

John Gentile wrote:
> 
> I've always hated using Ehrlenmeyers for boiling agars. For me the best
> flask is a flat bottom round glass flask with a long neck. I brought the
> solution to a boil on a stirring hot plate and stopped exactly 1 minute
> after boiling. Timing is everything. I would place the melted or autoclaved
> agar into a 50 C water bath until I was ready to decant. To pour large
> volumes I used a BD glass syringe with a valve attachment and a canula. The
> valve was "one way" and had 2 ports - the side port had a tube that went
> into the agar flask and the front port had the canula attached. It worked
> very well for 1 or 2 liters.
> 
> When I had to make XLD agar it was a little different - I used a thermometer
> to gauge the melting and didn't let it get over 98 C. Boiling it would
> usually cause the bile salts to precipitate out.
> 
> Firm agars have 15 gms agar per liter and semisolid agars have 5 gms per
> liter. But in either case you have to boil the agar for 1 minute and don't
> let it boil over or scorch on the bottom of the flask.
>




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