We perform media qualifications for the clients that supply compendial waters
to us for testing in order to find the combination of media, temperature,
filter porosity and incubation time that gives us optimal growth of
microorganisms. We test using SMA and R2A (and on occasion TSA just for comparative
purposes) using several incubation temperatures (20 to 25C and 30 to 35C), membrane
filters (0.2um and 0.45um), volumes (100 ml, 10 ml and 1 ml) and incubation
times (3, 5 and 7 days). We are looking for the best counts in the shortest
amount of time. We have found that almost every water system has a unique
microbial ecology and that those parameters change for almost each client.
The one media I have seen that never has better counts that SMA or R2A is TSA
(occasionally equal). I would think that an auditor would have a tough time
accepting TSA for Heterotrophic plate counts in compendial water without proof
that it does recover more organisms than the other "accepted" media.
Perritt Laboratories, Inc.
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.
AAI - http://www.aaiintl.com/Micro.htm
Accugenix - http://www.accugenix.com/
Becton Dickinson Microbiology Systems - http://www.bd.com/industrial
Microcheck - http://www.microcheck.com/
MIDI, Inc. - http://www.midi-inc.com/
Microbial ID, Inc. - http://www.microbialid.com/
MicroTest World Class Services - http://www.microtestlabs.com/
MIDI Labs, Inc. - http://www.midilabs.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