Would you want to be able to see poop smears?
I read a newspaper article some years ago in which the newspaper went to eateries around the city, ranging from greasy spoons to hoity-toity Michelin-listed restaurants, and swabbed a whole bunch of surfaces, which they then sent to a lab to have tested for the presence of fecal matter.
The results were not pretty.
Not a single restaurant was poop-free. There was poop on the silverware and poop on the tables. Poop on the plates and poop on the doorknobs. Every conceivable surface was coated with poop.
If it was possible for you to be able to see otherwise invisible fecal contamination, would you want to? You’d be able to avoid using poop-smeared cutlery, but I imagine every restaurant would look like the toilet stalls at Grand Central Station.