CamelBak bite-valves are made on a machine that uses flour to keep the pieces from sticking together. Last I heard, the guy giving the presentation was working for a company that could make CamelBak bite valves four at a time (instead of one) and it also didn't require flour. However, I don't know if CamelBak ever ordered the machine.
So, just some food for thought to somehow clean your bite valve before you hit the trail, bike path, etc. I couldn't think of thorough enough way (they are a little tacky) so I just reused the one I used last year prior to being diagnosed. Rinsed with bleach of course. :)