A slicing machine for cutting agricultural produce items includes a conveyor plenum with a plenum top plate formed with many vacuum ports arranged in a longitudinal direction below the gap between conveyor belts in a dual-belt conveyor, a water jet knife positioned to emit a stream of high-pressure water between the individual belts in the dual belt conveyor with enough force to cut a produce item into separate pieces, and a belt shaker configured to strike the dual-belt conveyor at cyclical intervals.