PMFLIST Archives

May 2011

PMFLIST@LISTS.MICROBIOLOGYNETWORK.COM

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
"Jerry R. Nelson" <[log in to unmask]>
Reply To:
The Pharmaceutical Microbiology Forum Email List <[log in to unmask]>
Date:
Thu, 5 May 2011 21:15:07 +0000
Content-Type:
text/plain
Parts/Attachments:
text/plain (143 lines)
Jackie,

The effective filtration area (EFA) will vary significantly between filter housing manufacturers.  The EFA may be as low as 9.6 sq cm to as high as 14.5 sq cm (from my experience).  Filter some stain then measure the stained area (EFA) for the 47mm membrane filter housings you use. Measure the size of the grids (center of line to center of line) and calculate the actual ratio of the grids to the EFA.  Most manufacturers make their grid squares 0.1 sq cm.  If you count 2 in a square and you have a 9.6 sq cm housing the mathematical conversion is 96 x 2 =  approximately 192 CFU.  If your membrane filter housing has a 14.5 sq cm EFA, then the mathematical calculation is 145 x 2 =  approximately 290 cfu.   Obviously EFA makes a huge difference.  Membrane EFA is a parameter that should be validated in each laboratory (or for each membrane filter housing type used in the laboratory).

jrnelson

	 




-----Original Message-----
From: The Pharmaceutical Microbiology Forum Email List [mailto:[log in to unmask]] On Behalf Of Lagomarsino Mónica
Sent: Monday, May 02, 2011 5:55 AM
To: [log in to unmask]
Subject: Re: [PMFLIST] Filter Counting

Jackie
See "Standard Methods for the examination of water and wastewater".
21st. ed: Part 9000, 9215A.8, b) 

Hope this helps
Mónica

-----Mensaje original-----
De: The Pharmaceutical Microbiology Forum Email List [mailto:[log in to unmask]] En nombre de Jackie Killingsworth Enviado el: Miércoles, 27 de Abril de 2011 01:49 p.m.
Para: [log in to unmask]
Asunto: [PMFLIST] Filter Counting

To All:

The company I currently work for filters water through a micron filter and then plates the filter on the appropriate media for the test needed.
If there are more than 2 colonies in a square on the filter they are using some crazy formula to estimate the count that usually winds up in an alert or action limit excursion.  To me if you can count every colony you should do so, but if you can't does anyone have a formula they use to estimate the count or know where I can get one so it is properly documented in procedure?

Thanks,

Jackie

------------------
The PMFList (http://microbiol.org/PMFList_info.htm) is operated from The Microbiology Network (http://microbiol.org) and supported by our sponsors (http://microbiol.org/sponsor.htm) as a service to the scientific community.

Please take a second to visit our sponsors' web sites and say thank you for their support of this service.

Accugenix - http://www.accugenix.com

American Type Culture Collection - http://www.atcc.org

BD Diagnostic Systems - http://www.bd.com/ds/

Biolog - http://www.biolog.com

Biomerieux - http://industry.biomerieux-usa.com

Biotest - http://www.BiotestUSA.com/micro

MicroBioLogics, Inc. - http://www.microbiologics.com

Millipore - http://www.millipore.com

MODA Technology Partners: now a LONZA company http://lonza.com/moda

Pall - http://www.pall.com

NovaTek International - http://www.ntint.com

Rapid Micro Biosystems - http://www.rapidmicrobio.com  (formerly GPS)

Veltek Associates, Inc - http://www.sterile.com

=================================
The nature of this service is to provide a medium for communication.  The specific statements and endorsements of individuals participating in the discussions are not necessarily those of The Microbiology Network, Inc., the PMF, or the sponsors of the list.

Piense en el medio ambiente antes de imprimir este mensajeAVISO DE CONFIDENCIALIDAD La información contenida en este e-mail, así como en sus eventuales adjuntos, es de carácter confidencial y protegida por la ley. Su uso está reservado exclusivamente para el destinatario, quedando prohibida su reproducción por cualquier medio. Si Ud. ha recibido este e-mail por error, favor notifique a GADOR reenviando este correo electrónico a su remitente, borrando ó eliminando posteriormente el mismo. Agradecemos su colaboración. CONFIDENTIALITY NOTICE The information contained in this email and in any of its attachment/s is confidential and may be privileged. It is intended for the use of the individual or entity named above. Therefore, its unauthorized use, disclosure or copying are strictly prohibited. If you have received this email by error, please notify GADOR immediately by returning this e-mail and destroy all copies of this message and any attachment/s. Thank you for your cooperation. 

------------------
The PMFList (http://microbiol.org/PMFList_info.htm) is operated from The Microbiology Network (http://microbiol.org) and supported by our sponsors (http://microbiol.org/sponsor.htm) as a service to the scientific community.

Please take a second to visit our sponsors' web sites and say thank you for their support of this service.

Accugenix - http://www.accugenix.com

American Type Culture Collection - http://www.atcc.org

BD Diagnostic Systems - http://www.bd.com/ds/

Biolog - http://www.biolog.com

Biomerieux - http://industry.biomerieux-usa.com

Biotest - http://www.BiotestUSA.com/micro

MicroBioLogics, Inc. - http://www.microbiologics.com

Millipore - http://www.millipore.com

MODA Technology Partners: now a LONZA company http://lonza.com/moda

Pall - http://www.pall.com

NovaTek International - http://www.ntint.com

Rapid Micro Biosystems - http://www.rapidmicrobio.com  (formerly GPS)

Veltek Associates, Inc - http://www.sterile.com

=================================
The nature of this service is to provide a medium for communication.  The specific statements and endorsements of individuals participating in the discussions are not necessarily those of The Microbiology Network, Inc., the PMF, or the sponsors of the list.

------------------
The PMFList (http://microbiol.org/PMFList_info.htm) is operated from
The Microbiology Network (http://microbiol.org) and supported by
our sponsors (http://microbiol.org/sponsor.htm) as a service to
the scientific community.

Please take a second to visit our sponsors' web sites and say thank you for their support of this service.

Accugenix - http://www.accugenix.com

American Type Culture Collection - http://www.atcc.org

BD Diagnostic Systems - http://www.bd.com/ds/

Biolog - http://www.biolog.com

Biomerieux - http://industry.biomerieux-usa.com

Biotest - http://www.BiotestUSA.com/micro

MicroBioLogics, Inc. - http://www.microbiologics.com

MODA Technology Partners: now a LONZA company http://lonza.com/moda

Pall - http://www.pall.com

NovaTek International - http://www.ntint.com

Rapid Micro Biosystems - http://www.rapidmicrobio.com  (formerly GPS)

Veltek Associates, Inc - http://www.sterile.com

=================================
The nature of this service is to provide a medium for communication.  The specific statements and endorsements of individuals participating in the discussions are not necessarily those of The Microbiology Network, Inc., the PMF, or the sponsors of the list.

ATOM RSS1 RSS2