A food container is provided with a container body; a retaining ring; an inlet and outlet mechanism; and a cover. In response to securing the retaining ring to the inlet and outlet mechanism, securing the retaining ring to the container body, and connecting a second conductor to a second terminal of a micro switch, a pressure sensor pushes a resilient member to close the micro switch to supply power from a power source to a motor, a vacuum pump is activated by the motor, a plunger moves to block an open end of a second stop on a second pipe so as to remove air from the container body through a first pipe, the air is drawn into a closed space via an air inlet and a second opening, and the air enters the pressure sensor via a bossed hole, thereby producing a vacuum in the container body.