A system and method for measuring a quality parameter of a harvested crop (50) are provided. Specifically, the system is adapted to be carried by a harvesting device (H) such that a sensor (20) is enclosed in a controlled environment and such that the sensor is capable of precisely and reliably measuring the quality parameter while the harvesting device is in operation. The system includes a verification device (60) and an actuator device (25) contained within the controlled environment. The actuator device periodically conveys the sensor device to at least one of a verification position (70, 80, 110) relative to the verification device and a measurement position (100). Thus, the sensor device may be periodically and reliably referenced and/or validated while in use in harsh agricultural environments such that the sensor device is capable of accurately measuring the quality parameter as the crop is harvested.