Device and method for preventing foreign matters from adhering in dishwasher

Device and method for preventing foreign matters from adhering in a dishwasher, the device including a circulating pump including a washing motor for providing a driving source to pump up washing water from a sump, an impeller designed to receive driving force from the washing motor and rotate for pumping the washing water from the sump to spray nozzles, and a disposer designed to receive driving force from the washing motor and rotate, for removing foreign matters introduced together with the washing water, sensing means for sensing a rotation speed of the washing motor, and a system control unit for controlling a rotation direction and/or speed of the washing motor according to the rotation speed sensed at the sensing means, thereby preventing the washing motor from being restricted by food remnants to improve product reliability by providing means for effective removal of the food remnants adhered to the washing motor.