Killing everything is not a good idea!
Without getting too far into specifics, last March I spent a few days in the hospital because of a bacterial infection. The doctors gave me large amounts of antibiotics, first through an IV, then in pill form. The antibiotics did a good job of wiping out the infection, but a side effect was the drugs also killed off the so-called “good bacteria” in my digestive system.
I had to keep taking the antibiotic pills for a few weeks after I left the hospital, so it was about a month of some pretty severe diarrhea. Fighting off the infection was bad enough, but having my digestive system all messed up was just as unpleasant.
That said, I am all in favor of the UV lights described in the OP. It might be best to install those lights in the air conditioning systems of large public buildings. The air is continually sterilized of airborne pathogens as it circulates throughout the building.
I am also a long-time advocate of using somewhat harder radiation to sterilize food, to protect against things like E.Coli and salmonella.
https://www.epa.gov/radtown/food-irradiation
- Pete