Yes he would, if a health inspection would occur when that happend and he was caught doing that, the store would receive a heavy fine
Health inspectors can’t and don’t do surprise visitis (like Kashrus supervisors) that will burst into the room and catch him red-handed using the fruit knife to cut his bacon sandwich. He will have at least a few minutes, if not days, advance notice before the health inspector comes to the back of the store where he keeps the bacon.
Secondly, there is no law against using the same knife for fruits and bacon or cheesecake.