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October 1999

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Thu, 21 Oct 1999 21:58:28 +0800
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Can someone pls tell me what TTC is and what it's effects are?

Thanks

Tan
----------
> From: rfriedel <[log in to unmask]>
> To: [log in to unmask]
> Subject: Re: [PMFLIST] Inhibitory effect of TTC.
> Date: Thursday, October 21, 1999 5:45 AM
>
> I commented on this in a previous post back in April.
>
>     [I think most of us will be quite suprised to find out that every
> organism found on the Microbial Limit Tests' count plates is
> identified by FDA microbiologists (although regulatory bodies tend to
always
> air on the side of safety and sometimes overkill).       This was
discussed
> by Dennis Guilfoyle of the FDA Brooklyn facility at the Spring 1999 AAI
> seminar.  To those of us utilizing          the pour-plate method for
plate
> counts, this requirement would be quite cumbersome particularly with
> colonies in close                  proximity to one another within the
> depths of the agar medium.  I would like to see the procedure as to how
one
> would choose      one colony over another when it found to be within the
> agar.  I can see the utility when the spread plate is utilized but the
issue
> becomes quite cloudy when it comes to pour plating; not to mention the
> presence of product interfering with the
decision
> process.  It is interesting to note that the FDA laboratories utilize
> methods which are derived from the Bacteriological      Analytical Manual
> (BAM) published by the AOAC (i.e., they use Letheen Broth instead of
TSA+LT)
> while we are guided/bound      (for the most part) by the methods
outlined
> in USP]
>
> I try to think in practical terms most of the time.  In a previous
> microbiological life, we set up a tier system.  We used a lower
> specification and an upper specification.  If the count fell in between
the
> lower and the upper specification, we would identify the organisms found
and
> compare them with the specification for that particular dosage form & its
> route of administration.  If the organisms of interest to that particular
> product were absent, the product passed.  If they were present, the
product
> failed.  If the product fell below the lower specification, it passed.
If
> the product exceeded the upper specification, it failed.  USP indicator
> organisms were used in the criteria as well as potential spoilage and
> clinically significant organisms.  All the organisms cited as
objectionable
> had to be recoverable using USP methodology.
>
> We need to better ascertain the relationship between "numerical counts,
> organism types and routes of administration" when setting our
> specifications.  Even if the organism has been shown to be pathogenic in
> certain instances, it still has to be present in a quantity sufficient to
> cause infection.  Just because it is there doesn't necessarily mean that
> infection will ensue.  We also need to place more emphasis on building
> quality into our processes and building an understanding of  microbiology
in
> terms the "person on the manufacturing line" can understand.  Other
> colleagues (chemists, pharmacists, etc..) in the non-microbiological
> disciplines would also benefit.  One sure-fire way to get a hands-on view
is
> to test the microbiota present on their hands using a RODAC plate.
"SEEING
> IS BELIEVING".  You can tell someone till you're blue in the face but
until
> they see a simple example for themselves, change will continue to
progress
> at a slow pace.
>
> Robert R. Friedel
> Quality Assurance Manager
> Laboratory Research & Analysis Groups
> Perritt Laboratories, Inc.
> http://www.perritt.com
> [log in to unmask]
>
>
> ----- Original Message -----
> From: Lynch, Karen <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Wednesday, October 20, 1999 4:12 PM
> Subject: Re: [PMFLIST] Inhibitory effect of TTC.
>
>
> > Katherine,
> >
> > Yes, this is for Total Aerobic Microbial Count, and you're right that
it
> > would be a big job to subculture every colony if for example there were
40
> > colonies detected.  Although we also perform additional tests to test
for
> > the absence of the USP indicator organisms, colonies detected in TAMC
> should
> > be identified to some extent to ensure that they are not objectionable
> > microorganisms other than the USP indicators.
> >
> >
> > Karen Lynch
> > Parke-Davis Research
> >
> >
> > -----Original Message-----
> > From: Shih, Katherine [mailto:[log in to unmask]]
> > Sent: Friday, October 15, 1999 4:36 PM
> > To: [log in to unmask]
> > Subject: Re: [PMFLIST] Inhibitory effect of TTC.
> >
> >
> > Karen:
> >
> > Is this for the Total Aerobic Microbial Count?  If you have recovered,
> say,
> > 40 colonies, this would be a big job to subculture every colony as we
can
> > not group them by colony morphology.  For TAMC, do we need to check
every
> > colony that we have recovered if we also have other tests side-by side
for
> > the absence of certain objectionable organisms?  Thanks.
> >
> > Katherine Shih
> > Oread
> >
> > -----Original Message-----
> > From: Lynch, Karen [mailto:[log in to unmask]]
> > Sent: Friday, October 15, 1999 9:02 AM
> > To: [log in to unmask]
> > Subject: Re: [PMFLIST] Inhibitory effect of TTC.
> >
> >
> > Laura,
> >
> > We use 0.5% TTC in our lab to help us differentiate colonies from
> particles.
> > We run our test with media that does not contain the TTC and at the end
of
> > the incubation period, we flood the plate with the TTC and allow it to
> stand
> > for about one hour to allow it to soak into the media and reach the
> > subsurface colonies.  We then subculture the colonies immediately and
have
> > not yet had any problems with recovery.  This method has worked quite
> nicely
> > for us.  We have no experience with adding the TTC to the media prior
to
> > pouring the individual plates, so I cannot comment on the inhibitory
> effects
> > of the TTC when used in that manner.
> >
> > Karen Lynch
> > Parke-Davis Research
> >
> >
> >
> >  -----Original Message-----
> > From: Laura Acevedo [mailto:[log in to unmask]]
> > Sent: Thursday, October 14, 1999 6:33 PM
> > To: [log in to unmask]
> > Subject: [PMFLIST] Inhibitory effect of TTC.
> >
> >
> >
> > Dear colleagues,
> >
> > I perform microbial limit tests using poured plates . With some
products
> > (lactose, starch) it is difficult to distinguish the colonies. I know
> > there`s the recomedation of using MPN in this cases, but I wonder if it
is
> > possible to use poured plates adding  TTC to the culture medium to
stain
> the
> > colonies and differentiate them from the product being tested. Has
anybody
> > validated this method? I`ve heard about possible inhibitory effect of
TTC.
> > Could someone refer me any paper on this topic?
> > Any help would be appreciated, thanks in advance,
> >
> > Laura Acevedo
> > Microbiological Quality Control Manager
> > Laboratorio LIBRA
> > Montevideo-Uruguay
> > [log in to unmask] <mailto:[log in to unmask]>
> >
> >
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>
>
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