Abstract: A container system includes a one-piece, one-way valve. The container system can be evacuated by pressing the lid, thereby forcing air out of the one-way valve. The one-way valve does not allow air to enter the container system. The one-way valve includes an interface or release which allows air to enter the container system when the interface is pressed. The one-way valve is preferably an umbrella-shaped valve made of a silicone or plastic.

Abstract: A container system is optimized for use as a microwave steamer. The container system includes a container, a lid, and a colander disposed between the lid and the container. The colander has smooth sides and integral hand grips. The integral hand grips vent vapor trapped between the colander and the container and allow easy lifting of the colander from the container. The colander also includes slot-like longitudinal openings on a side wall. Additionally, the lid includes a vent aperture which is a grate that prevents spattering of liquids from the container system. The lid is sealably engaged to the opening of the container.