You don't. People have been reading in the bathroom for decades. You're getting little shit particles in your nose regardless of whether you read in there.
The point being we all interact with fecal matter way more than anyone would like to know - even just by smelling.
It's been a topic for climbing gyms [1] and have heard the same for hand shakes but no link provided
[1] https://www.climbing.com/news/study-finds-fecal-veneer-on-gy...