A food waste disposer system includes a grinding mechanism. The grinding mechanism includes a stationary grind ring and a rotatable shredder plate assembly. A detector is connected to the grinding mechanism to detect the presence of a foreign electrically conductive object in the grinding mechanism. In an aspect, the detector detects that a foreign electrically conductive object is in the grinding mechanism upon sensing that an electrical circuit has been completed between the stationary grind ring and the rotatable shredder plate.