Abstract: A steam processor capable of operating in a convection or a pressure mode. The processor includes at least one insulated cooking chamber having an access door for gaining access to the interior, a steam inlet for introducing steam into the chamber and a steam outlet for discharging excess steam and condensate. A drain manifold connects the steam outlet to an ambient drain and includes a fluid pressure operated pinch valve for terminating communication of the steam outlet with the drain in order to place the cooking chamber in a pressure mode. A latch mechanism maintains closure of the access door as long as the cooking chamber is under pressure and includes a solenoid operated locking bar which blocks movement in a door opening latch member. A pressure responsive actuator monitors pressure in the cooking chamber and maintains the locking bar in its blocking position as long as the pressure in the cooking chamber is above a determined level, even if power is interrupted to the steam processor.