Do you always wipe down gym equipment before you use it? Do you re-wash all the dishes at work before you use them? If not, then you're really not that germ phobic, because any germ-a-phobe would NEVER trust a treadmill was wiped down by the last stranger to use it. Same is true of dishes. 

So, you're just looking for reasons to judge your co-worker and prove yourself superior to her. That's your problem; it's NOT hers to fix. If you confront her and it doesn't go well, you can then assume she's sneezing/coughing on everything you own the second you walk out of the room. Congrats, all you've done is make it worse.... and no, that's not proof you're superior to her.