Abstract: A container sensing system for controlling the heating in a microwave oven of a container carrying control information which may be read by an optical reading device. The optical reading device includes a light transmitter and a light receiver for sensing a reflectance of a sensor. The sensor includes a first and second region. The first region is provided for establishing a start and non-start condition while the second region is provided for reading temperature information. To avoid the surface reflected portion of incident light to gain an accurate reading, the axes of transmission and reception are offset in the same angular direction to a perpendicular of a sensor surface wherein the transmitter directs an inclined reading light beam onto a region of the sensor and the receiver receives the scattered light therefrom depending on the reflection properties of the sensor region.