In the grand scheme of things that can go wrong in life, this seems pretty trivial

I'm a firm believer in the concept of taking basic hygiene precautions and nothing more - and not worrying too much about things the drinking straws the OP has concerns over. So showering once a day (you know, most Brits still only bath once a week), washing hands after using the washroom and before eating - and that's about it.

I work / have worked with folk who seem obsessed with the type of issues the OP mentions (one chap used to bring antiseptic wipes to work and if anyone used the phone / pen / stapler on his desk he would then carefully wipe it). But in every case, these people seemed to get every bug, cough, sneeze etc going and seemed to have far more time off sick than anyone else - probably because their immune system has been so wrapped in cotton wool it can't fight off even the slightest infection.

That said, I once read a good tip when travelling about taking along a small zip type plastic bag to put the TV remote control into if the hotel room has certain types of PPV movies. Apparently some tests were done by public health at a hotel and the TV remote was found to have 14 different urine traces and 18 different traces of, well, you can imagine I am sure!. So I do always have a small plastic see-through bag in my luggage