[Microbiology] Re: Question on a MacFarland Standards

John Gentile via microbio%40net.bio.net (by yjgent from nospamcox.net)
Fri Oct 10 20:38:26 EST 2008


On 2008-10-10 17:08:25 -0400, "Rivera Morales, Luis [JR]" 
<luis.rivera from medtronic.com> said:

> Hi, Mr. Friedel
> 
> I saw you e-mail on the internet when I was searching for how to create
> microorganism supension with a know population?  I know that some people
> use MacFarland Standard, but We don't have MacFarland Standard, we have
> Densichek colorimeter by biomeriuex.  Please, would you tell me how can
> I prepare those kinds of microbial suspension given a know concentration
> (for example, 10e6, 10e7 or 10e8).
> 
> Thank you very much,
> 
> Luis Rivera Morales
> Associate Microbiologist/Sterilization
> MPROC-Juncos
> Phone: 787-561-2840
> Fax: 787-561-2413
> 

Luis,
	The bioMeriuex colorimeter usually comes with 4 tubes with McFarland 
Standards 0.5, 1, 2, 3 and 4. These are made with latex particles and 
are very stable.The colorimeter should have colored sections on it 
relating to the 4 standards.

	You can also make your own standards using a formula with Barium 
Chloride and H2S04. A Google search found several sites that had the 
recipie, and Wikepedia even has a chart of each standard up to 4 with 
approximate bacterial concentratioin and nephelometer transmittance and 
absorbance for each one. I tried to copy it into this message but it 
did not format correctly.


--.
John Gentile
Newsletter editor
Rhode Island Apple Group
-- 
John Gentile MS, M(ASCP)
Laboratory Information Mgr.
VA Medical Center
Providence, RI 
yjgent from cox.net



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