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October 2005

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Subject:
From:
"Hewitt, Jackie" <[log in to unmask]>
Reply To:
The Pharmaceutical Microbiology Forum Email List <[log in to unmask]>
Date:
Fri, 7 Oct 2005 08:19:58 -0400
Content-Type:
text/plain
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text/plain (240 lines)
Hans,

This was personal observation from qualifying test recovery from a water
treatment system in a new building. As part of that study, I compared the
filtration method with spread plate counts and was very surprised to find
much lower recovery on the filters. These were deionized waters that had
indigenous water organism counts. It was repeated with a significant number
of samples (I can't remember how many as it was some years ago at a
different company) but the results were consistent. I qualified my original
statement by saying "depending on flora and process" because when I repeated
the study in my current company, there was little difference between
filtration and spead plate counts.  I believe it is dependant on those
factors, and we definitely have a different normal environmental flora here
(Long Island, NY compared to King of Prussia, PA).

Best Regards,

Jackie Hewitt
Microbiology Manager
Luitpold Pharmaceuticals
PO Box 9001, Shirley, NY 11967-9001
Tel. (631) 205-2321
Fax. (631) 205-2375
e-mail: [log in to unmask]
 


-----Original Message-----
From: [log in to unmask] [mailto:[log in to unmask]] 
Sent: Thursday, October 06, 2005 7:13 PM
To: [log in to unmask]
Subject: Re: [PMFLIST] TABC testing of Purified Water by Pour Plate method


 
Jackie, very interesting!  Is the comparison of spreading, pour  plate and 
membrane methods published anywhere?  I would love to see  the data!
 
Best regards, Hans
 
 
Hans G. Schroeder, Ph.D.
International  Consultants Association
132 N. El Camino Real # 318
Encinitas, CA 92024 -  USA
Fax/Phone: + 760-753-0790
[log in to unmask]

 
 
 
In a message dated 10/6/2005 3:03:33 PM Pacific Daylight Time,  
[log in to unmask] writes:

Pour  plate counts often do require longer for the colonies to   become
easily visible and countable due to being surrounded by agar. The  actual
counts should be comparable. The USP probably recommends pour plate  because
you will get discrete colonies with minimal spreading from this  technique.
R2A is the most commonly used medium for purified water testing  and if
incubated for 7 days will usually give the highest count (although I  have
done comparisons in some places where Plate Count Agar was just as  good and
could be incubated for a shorter period). 
Although a 1 mL  sample may be tested by membrane filtration by adding the
sample to sterile  water in the filter cup, counts may be significantly
lower, depending on  the water flora in your plant and conditions of your
water tretment process  . This may be attributed  to the difference in
accessibility of the  nutients to the bacterial cells on a filter on the
agar as opposed to being  directly in contact on the surface of the agar.

Jackie  Hewitt
Microbiology Manager
Luitpold Pharmaceuticals
PO Box 9001,  Shirley, NY 11967-9001
Tel. (631) 205-2321
Fax. (631)  205-2375
e-mail: [log in to unmask]



-----Original  Message-----
From: Singh.Gurbir [mailto:[log in to unmask]]  
Sent: Wednesday, October 05, 2005 11:22 PM
To:  [log in to unmask]
Subject: [PMFLIST] TABC testing of Purified  Water by Pour Plate method


Hi All,
We are doing TABC (Total  aerobic bacterial count) by pour plate method for
purified water. Our  specifications are below 100 cfu per ml.  Incubation
Temp. is 32.5  2.5 degree C, time is 72 to 96 hours. Results are good. We
are using pour  plate method as it is recommended in USP. But when I tested
some purified  water samples for experimental purpose with both pour plate
(1ml) &  spread plate (0.1 ml x multification factor 10) .Results in both
the techniques were approximately same, but in case of spread plate,  fully
developed colonies appeared in 48 hours at the same temperature i.e.  32.5
2.5 degree C but in case of pour plate it took 96 hours of incubation  &
even then colonies were comparatively small. Media remained the same  in
both the cases i.e. soyabean casein digest agar., Other conditions  required
for pour plate were also perfect i.e. before pouring agar is  maintained at
43 degree C.This experiment I have repeated a no. of times  & now I have
strong feeling i.e. spread plate technique when used for  purified water
gives a better or same recovery & less incubation time  is required .Whether
other members have done similar studies & what's  there feeling. Can they
explain me If spread plate technique gives better  results, why USP
recommends Pour plate technique.

All information  will be greatly appreciated.

Thanks & Regards

Gurbir  Singh
Microbiologist, DSM group


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Biomerieux -  http://industry.biomerieux-usa.com/
Dupont Qualicon -  http://www.qualicon.com
EMSL Analytical, Inc. -  http://www.emsl.com
Genomic Profiling Systems, Inc. -  http://www.genprosys.com Microcheck Inc,
Microbial Analysis  Laboratory - http://www.microcheck.com MicroTest World
Class Services -  http://www.microtestlabs.com/ MIDI Labs -
http://www.midi-inc.com/ Millipore - http://www.millipore.com/ NovaTek
International - http://www.ntint.com Raven Biological Labs -
http://www.ravenlabs.com Veltek Associates, Inc -  http://www.sterile.com

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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/
ATS Laboratories - http://www.ats-labs.com
Biolog - http://www.biolog.com
Biomerieux - http://industry.biomerieux-usa.com/
Dupont Qualicon - http://www.qualicon.com
EMSL Analytical, Inc. - http://www.emsl.com
Genomic Profiling Systems, Inc. - http://www.genprosys.com Microcheck Inc,
Microbial Analysis Laboratory - http://www.microcheck.com MicroTest World
Class Services - http://www.microtestlabs.com/ MIDI, Inc. -
http://www.midi-inc.com/ Millipore - http://www.millipore.com/ NovaTek
International - http://www.ntint.com Raven Biological Labs -
http://www.ravenlabs.com 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.
Confidentiality Notice: This e-mail transmission may contain confidential or
legally privileged information that is intended only for the individual or
entity named in the e-mail address. If you are not the intended recipient,
you are hereby notified that any disclosure, copying, distribution, or
reliance upon the contents of this e-mail is strictly prohibited.

------------------
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/
ATS Laboratories - http://www.ats-labs.com
Biolog - http://www.biolog.com
Biomerieux - http://industry.biomerieux-usa.com/
Dupont Qualicon - http://www.qualicon.com
EMSL Analytical, Inc. - http://www.emsl.com
Genomic Profiling Systems, Inc. - http://www.genprosys.com
Microcheck Inc,  Microbial Analysis Laboratory - http://www.microcheck.com
MicroTest World Class Services - http://www.microtestlabs.com/
MIDI, Inc. - http://www.midi-inc.com/
Millipore - http://www.millipore.com/
NovaTek International - http://www.ntint.com
Raven Biological Labs - http://www.ravenlabs.com
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.

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