How should the safety-door interlock of a meat grinder be tested?

Start by opening the guard while the auger is running: the drive must cut out promptly, so time the stop with a tachometer or stopwatch rather than relying on visual judgement. Then check restart behaviour—pressing start with the door ajar should do nothing, and on most models the machine must be manually reset after the door closes instead of resuming on its own. Where a safety relay is fitted, log its trip and reset signals. Record the interlock type, reset method and measured results on the acceptance sheet for that unit, signed off, and use it as the benchmark for later machines of the same model.