Bruises on potatoes: is it enough to cut them away?. Bavarian State Agricultural Institute: Black spots are usually caused by physiological disorders, pressure points in storage in spring and impacts.
Unpleasantly smelling, wet and already infected tubers should be “removed immediately” The authority also recommends consumers to only store dry potatoes, to prevent bruising and to store the potatoes “dark, well ventilated, at approx. 5-8 °C and high humidity”