Well, I know that variants of this issue has been addressed in the past, but I'll ask my own version:
I use a Sawyer squeeze filter for my backpacking trips. For convenience, a tornado tube is used to connect the filter output with a clean water bottle. When I'm done filtering, I screw caps onto the filter input and output as well as the dirty water bottles (evernew) and throw all this into a pocket in the backpack. I generally don't put any unused clean water bottle or the tornado tube in the same pocket. Now, I suppose there is no real risk of contamination of the unused clean bottle if I screw its cap on securely, but I'm still reluctant to throw my tornado tube in with the rest of the stuff. This is out of concern that the tornado tube may come into contact with dirty water on the outside of the filter or the outside of a dirty water bottle. Are these concerns unfounded? Are a few drops of dirty water on the tornado tube any cause for worry?