http://waterindustry.org/Water-Facts/filtered-1.htm

In terms of bacteria, however, Brita water filters do not aid to kill the microorganisms.

http://www.brita.net/uk/faqs_contami...ml?L=1&cat=7#1

Can bacteria or viruses be filtered out (On Tap)?
The technique of a carbon block is not designed to filter out bacteria or viruses.