agars

lamb L.A.M.Buisman at chello.nl
Thu Jul 5 16:11:09 EST 2001


Larry Farrell wrote:

> Am I simply overlooking something here or does this completely miss the need to
> sterilize the medium?  Just because the agar has been melted and mixed into a
> medium does not mean that the medium is sterile.  Even pre-mixed media containing
> agar must be sterilized, and sterilization in an autoclave heats the medium long
> enough and hot enough to melt the agar.  Of course, it still needs to be mixed
> after removal from the autoclave, once it has cooled enough that it doesn't boil
> over when you mix it, to assure that the molten agar is evenly mixed throughout
> the medium.

Seems likely, for water analysis ....

Do you happen to know why is it that according to the handbooks agar always has to be
dissolved by boiling before autoclaving?
We never do, it costs time, it is dangerous, and we want the exposure to heat as
short as possible. After autoclaving we place the erlenmeyers in a waterbath with
magnetic stirrers until adding supplements and pouring.
For larger batches we have nice automatic thingsies, can't think of th English word
for them.

Loes




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