a method and apparatus for even and rapid heating , pasteurization or sterilization of products contained in a package , such as , for example , pharmaceutical products or food , which are conveyed through a microwave treatment chamber on a continuous conveyor belt . in order to heat components of the products having different heat absorption for the purpose of reaching the pasteurization temperature rapidly and evenly , the temperature of the components is recorded by a temperature sensor , and on the basis of this the computer calculates the respective δt , taking into account given product parameters and the desired temperature to be reached . when the product passes under the following input aperture , a given microwave energy level is coupled into each specific component , as a result of which an even temperature of all products in the package is achieved very rapidly without overheating of the product .