The oven (1) has a ventilation hood connection (9) connected to a vacuum pump (11) and projected through a rear wall of a cooking chamber (2). A pressure sensor is provided in or at an extraction line (10) that connects the vacuum pump with the hood connection. The pressure sensor is connected with a control unit for setting negative pressure, where the oven is arranged to generate the negative pressure during a heating period. A heat generating element (13) is arranged at an upper side of an accessory lower part (4). An independent claim is also included for a method for treating foods in an oven.
