[Microbiology] Re: Rodac Plates

John Gentile via microbio%40net.bio.net (by yjgent from nospamcox.net)
Tue Oct 6 18:49:53 EST 2009

On 2009-10-05 11:41:10 -0400, "Cherie Parker" 
<cherie_parker from amsinomedusa.com> said:

> We use Rodac (contact) plates for our environmental monitoring. Is there a
> method to estimate TNTC plates? How do you read spreader colonies on a
> contact plate? Is there a standard method for counting colonies on a Rodac
> plate?
> Cherie Parker
> Amsino Medical USA
> 1150 Antioch Pike, Suite 200
> Nashville, TN 37211
> Ph:615-332-9959
> Fax:615-831-1817
> cherie_parker from amsinomedusa.com

I thought contact plates went out with bleeding times. I don't think 
there are any clear meaninful guidelines for how to quantify plates. 
What may be an acceptable count now may be TNTC in a few hours. The 
environment is rather dirty so what is the purpose? To try to educate 
someone on how to clean? It might be more important to examine what 
cleaning solutions they are using. Most cleaning crews I've run into 
seem to make the strongest formula they can instead of going by the 
manufacturers directions. How many times have you walked into a public 
bathroom and been assaulted by the fumes of the disinfectant? If a 
solution works best at 2% it doesn't work better at 10 or 20%, but look 
at what they are doing. Even in our lab, most of our bleach solutions 
were much more than the 5% recommended. After washing a bench down, it 
sometimes smelled like an over chlorinated pool!
 We stopped doing any environmental cultures because no one could 
interpret them.
John Gentile MS, M(ASCP)
Laboratory Information Mgr.
VA Medical Center
Providence, RI 
yjgent from cox.net

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