There are lots of areas (air ducts, etc.) in a fridge which are not accessible without at least some dismantling of the appliance. If the smells are originating from there, just wiping out the interior will not likely solve the problem.
If you can't or don't what to resort to that, you may need to call an appliance service technician to check those areas for you.
BTW. At least one manufacturer had a problem with the defrost water drain pan *out side of the fridge* smelling like urine. In that case the material the pan was made from was the problem and needs to be replaced.