More on Re: using 100% as decontaminant in cryostat

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From:Gayle Callis <>
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Thanks Tim, 

That's what I thought, about the 70%.  One can pick up the trimmings with a
guaze pad wetted with 70%, the trimmings adhere, and you can put this into
a biohazard bag afterwards.  We do this routinely, to minimize the "flying
trimmings" syndrome, the cryostat stays much cleaner until the next time it
is used without a major breakdown/defrosting.  This could be done at the
end of a day or in a low volume cutting setting, at the end of a sectioning
session.   Don't "slop" a lot of the 70% around, it contains enough water
to make the cryostat build up frost, or in my case Mt Everest ice climbing
pinnacles in the back THEN a major defrost/cleaning.  A kimwipe also works,
and if there is any residual 70% sitting on surfaces, go to the 100% to
sponge up the water, usually a bit frozen, but 100% makes a nice antifreeze.

Ah the joys!

>Date: Mon, 06 Mar 2000 08:33:02 -0500 (EST)
>From: Tim Morken <>
>Subject: More on Re: using 100% as decontaminant in cryostat
>The literature shows that 70% is a better disinfectant than 100% alcohol. 
>People use 100% alcohol to get rid of the water in the cryostat after 
>There is plenty of litererature on how best to clean surfaces (benchtops, 
>walls, floors, glassware) and how to clean freezers and refrigerators, so 
>the methods are there. What is not clear is how that works with a cryostat 
>where shavings may sit for awhile (days, weeks?) before being cleaned up. 
>How do you best clean a piece of machinery that is exposed to, and often 
>caked with, contaminated tissue? How common is it for the cryostat to have 
>living pathogenic organisms it it at any given time?
>Tim Morken, B.A., EMT(MSA), HTL(ASCP)
>Infectious Disease Pathology
>Centers for Disease Control
>1600 Clifton Rd.
>Atlanta, GA 30333
>Phone: (404) 639-3964
>FAX:  (404)639-3043
>----Original Message Follows----
>Subject: Re: using 100% as decontaminant in cryostat
>Date: Sun, 05 Mar 2000 19:27:33 -0500 (EST)
>It is my understanding that absolute is not a good disenfectant, because a
>certain water content kills bacteria, my main concern are and is the viral
>contaminents,AFB, HIV, especially with the multi-drug resistant species
>cropping up.  Bleach or 10%
>sodium hypochlorite is used on work benches in the clinical labs where blood
>borne pathogens are concerned, shouldn't we be looking at what they are 
>as an adjunct to us? Are we not at the same risk? We may not have to
>re-invent the wheel here just look across our halls.                  Dana
>Get Your Private, Free Email at
Gayle Callis
Veterinary Molecular Biology
Montana State University
Bozeman MT 59717-3610
406 994-4705
406 994-4303

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