FBS troubles

[ivette emery]

I have had contamination in the last three bottles of FBS that I 
purchased from GIBCO (Life technologies).  After plating out 3 mls 
of FBS from previously unopened bottles, and incubating at 25oC 
overnight I see tiny organisms; I think is bacteria.  These little 
bugs go through 0.2um filters and are resistant to the Penn/Strep 
in my media.  I have been extra careful in handeling the FBS in my hood
to be sure I am not introducing the contamination myself and I have 
scrubbed my incubator to make sure it is not coming from there.  
Luckily, the replacement bottle that GIBCO sent me, that came in a 
plastic bottle, as opposed to the glass bottles I had, seems free of
my mysterious bug.  Has anyone else had this problem?

Ivette