Abstract: A method of continuously sterilizing foodstuff and an apparatus suitable for carrying out the method are disclosed. The invention, which permits a considerable saving in the amount of microwave energy to be achieved, is attained by providing a plurality of sequential stages in each of which the foodstuff is subjected to microwave radiation, the temperature of the article being sterilized being monitored in each stage and the amount of microwave energy being reduced from stage to stage in a stepwise manner in dependence upon the temperatures monitored.

Abstract: A method and apparatus for matching a microwave heater to reduce the microwave energy reflected by the load, wherein microwave energy from a microwave energy source is supplied to a treatment chamber by a hollow waveguide of rectangular section. A directional coupler in the waveguide prevents reflected energy returning to the source and directs it to absorption means. A detector is provided at the absorption means to measure the reflected energy and produce a signal, and control means is provided to operate control motors to operate tuning pins provided in the waveguide, the control motors having different operating speeds.