[Microbiology] Re: Question on a MacFarland Standards
(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
> Phone: 787-561-2840
> Fax: 787-561-2413
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.
Rhode Island Apple Group
John Gentile MS, M(ASCP)
Laboratory Information Mgr.
VA Medical Center
yjgent from cox.net
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