In my own kitchen, wood all the way. They're sturdier and the knife doesn't cut into them as easily. I always give a quick spray with Dettol after cleaning as well and have never had any problems/illness. We have plastic ones at school, with colour coded handles - broadly red for meat, blue for fish, green for veg and white for bread. They look very pretty, but whoever did the ordering didn't think the numbers through properly. We very rarely cook meat or fish with our primary school children. I guess it's different in secondary schools!