As far as I'm concerned, if it looks clean and has been rinsed out, the MLT is fine. The way I look at it is that even if there was something invisible living in there, I'm going to be boiling the wort that comes out within an hour or so & nothing will live through the boil. You are fine doing what you're doing.
Currently On Draft: Bamberger Rauch Dunkel, Belgian Blond, Pilsener Urquell clone, Smoked Porter
Bottled: Concord Pyment, Mi'Apa Sparkling Mead, Chimay Blue, Old Simcoe American Barleywine, Old Cantankerous
Fermenting and Conditioning: Pseudo-Decoction Munich Dunkel, Left Hook Bitter
Recently Kicked Kegs: Fresh Hop Pale Ale, Citra Rye IPA
On Deck: Old Rasputin, Northstar IPA, Ur-bock Dunkel