Beer is mainly H2O! RDWHAHB! The odds are pretty much zero that that sucked in water will do anything. There's a bunch of other microbes that are in the wort. Beer is never sterile: the best you can do is have an environment that favors a lot of yeast cells to take up shop and have an orgy. That's the best description of fermentation that I can think of. Keeping proper sanitation techniques will help reduce any chance of bacteria taking up shop and competing with those yeasties....and utilizing starters and aerating is the only true way to have a healthy yeast cell count that will have a clean ferment.
On Tap: Barleywine, Coffee Oatmeal Imperial Stout (big big beer)
Fermenting: Double Simcoe IPA
On the Bench: Racer 5 IPA
"One of the first things early caveman did, when he crawled out of the mudd, was to make beer. And cavemen everywhere are still making beer...and drinking beer." - Jean Sheperd