[Microbiology] Re: question

John Gentile via microbio%40net.bio.net (by yjgent from nospamcox.net)
Sun Nov 22 21:16:51 EST 2009

On 2009-11-22 10:37:25 -0500, Shalini selvam <lovey5dovey from hotmail.com> said:

> Hello there!To anyone concern:
> I have a question.
> How long can a media last after being autoclaved and where should we store
> it?can we autoclave it twice?
> And how do we set up microbial consortia?
> Thank.
> Regards,Shalini
> _________________________________________________________________
> Windows 7: Simplify what you do everyday. Find the right PC for you.
> http://windows.microsoft.com/shop

Generally media that has been dispensed into screw capped tubes will 
last a lot longer, especially if the caps are screwed tight after the 
media has cooled. Petri dish media dries out and needs to be sealed in 
a bag or container and usually requires refrigeration.
If you add blood to a media, it will shorten the "expriation date" 
significantly. I wouldn't trust blood media past 4 to 6 weeks.
If you make the media in large flasks, you must cool the agar to about 
50C and then pour into whaterver vial or plate you intend to use. It is 
not recommended to autoclave again since that could carmalize some of 
the sugars and may change some chemical properties and pH. You can 
remelt media by bringing it above the melting temp of agar which is 
around 97C, but don't go over that, just enough to get it all to melt.
There are a few good references for media preparation including the 
Difco Manual and the American Society of Micribiology Manual of 
Clinical Micribiology. These are the references I've used in my many 
years of media making and storing.

John Gentile MS, M(ASCP)
Laboratory Information Mgr.
VA Medical Center
Providence, RI 
yjgent from cox.net

More information about the Microbio mailing list

Send comments to us at biosci-help [At] net.bio.net