Even well done steak is not guaranteed to be free of food borne illness. You really need to know two variables - temperature and time, and one objective - kill

Even well done steak is not guaranteed to be free of food borne illness. You really need to know two variables - temperature and time, and one objective - kill rate. Time is the reason that it is safer to eat a sous vide rare pork chop than a grilled rare pork chop.