FBS trouble part2

ivette emery iemery1 at cc.swarthmore.edu
Tue Nov 7 16:06:11 EST 1995

Thanks for all the helpful comments I received.  Here are answers to  
some of your questions,

The FBS lots I had trouble with were: 37N7052 and 32K2646.
The new bottle I received lot 30P2155 looks good.

The bugs I see (or I think I see) are visible on an inverted scope at 
400X magnification but you have to concentrate to see the little dots 
moving about.  It helped when I would swirl the medium and I would get
a concentrated spot in the middle of the plate.

I took some contaminated media and passed it through a 0.2um filter
and after two days I saw the bugs again.  So I figured it went through
the filter albeit inefficiently.

I did call Life Technologies and they said no one else had complained
but that they would look into it.  I am expecting a call from them
sometime soon.

I guess it could be small precipitate undergoing brownian motion. 
This was, in fact, my first impression but I don't see this in the 
freshly opened medium from the fridge only after an overnight in the
incubator and there would be so much of it!  In another 
lot, like I mentioned, I didn't see the bugs.  I even asked a couple 
of people in my department to come and take a look.  It looked 
biological to others too.  Precipitate might still be the problem 
and different batches behave differently on this regard.

Maybe I am imagining the whole thing but one thing I am sure of, 
my project was working great until I started seeing this light cloudi
ness on my media that under 400X mag looked like tiny bugs to me.  I
hope this new batch of FBS solves my problem.

Thanks again for all your comments,

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