Thermal processing

A brief history of the thermal processing of foods is provided, and followed by an outline of the biomathematical theory upon which modern food processing techniques are based. The paper then proceeds to show how this well-established theory has been supplemented by applying the mathematical approach previously reserved for consideration of bacterial destruction to the destruction rate of essential nutrients. Recent developments in the field of high-temperature short-time (h. t. s. t.) processing are discussed with emphasis on problems connected with aseptic methods. As an alternative to aseptic filling, the use of ultra high filling temperatures is considered. Thin section containers, such as foil pouches, or the adoption of vacuum sterilization or flame sterilization techniques, afford the possibility of applying h. t. s. t. processes to filled and sealed containers. Problems encountered in using microwave energy for sterilization are outlined. In conclusion two recent experimental developments are described - fluid bed heating and cooling of containers and the helical pump sterilizer.