When you sanitize with bleach it's best to mix an equal amount of bleach and vinegar into the water you're sanitizing with. Bleach on its own won't kill certain bacteria unless the water has some acidity to it (hence the vinegar.)
It's important not to mix the vinegar and bleach directly, or you will end up with a nasty toxic cloud. Pour the bleach into the water, mix, then add the vinegar. There's an audio file here
http://www.basicbrewing.com/index.php?page=radio (March 27th) that breaks it all down.
I've done all my sanitizing with bleach/vinegar and never had a sanitation-induced infection.