That's good advice about phobia/obsession.
My daughter is a bit weird about germs. For example the other day, I was handling a deer skull that we found in the backyard, and she was a little put out that I touched a doorknob before washing my hands.
As a kid, I was the same way with germs. As an adult, I'm probably still a bit overly cautious. When COVID happened, I joked that it wasn't OCD, but rather it was training for a pandemic.
My observation of her behavior makes me wonder if it's a nature vs. nurture thing with her. Nurture: Did I accidentally teach her my phobia. Nature: does her brain (like mine) ruminate about everything, leading to phobias when the topic of ruminations is a scary thing like germs.
I'm not a germaphobe, but I think I'm with your daughter on this one. :)
Have you ever heard of prions, e.g. chronic wasting disease?
Cute story: I was having trouble getting my 4-year-old to brush his teeth until one night, I had to idea to show him this children's Q&A book that had a page about "why do I have to brush my teeth?" The little cartoon bacteria convinced him that brushing his teeth was a good idea. It was like a light switch in his head; I finished the page and he said, "daddy, I want to brush my teeth now" and walked off to the bathroom.