Have eaten of many wooden plankas in many different restaurants over the years and never had any problems so I have no qualms about using them.
On the other hand I have many qualms about the ethos of trying to kill all know bacteria. It's only by coming into contact with some bacteria that we humans build up resistance and playing in mud did me no harm..
I am more concerned about watching them cut all different meats on the same plastic board in Migros today...
Some of the best restaurants and busiest use them... Nil Bar, Bella Mammas, Buzz Bar, Mancero, Jamie Olivers places in UK etc etc
We all need a certain immunity to bacteria to be able to live and the only way to build up that immunity is to be exposed to it.