Microwave heating in the food industry

Food processing has become an important aspect of microwave heating; several technically and some economically successful developments have been reported over the past 10 years. However, the number of microwave installations in the food industry is still very small and not in proportion to the publicity given in many trade journals. The basic theory for the dielectric heating of foods is first reviewed and examples are given of the methods which can be used to analyze heating applications, a valuable complement to empirical testing. Present applications of microwave heating of foods are reviewed. Promising new applications of partial thawing, cooking, and sterilization are discussed in some detail. Some of the reasons for the apparently slow development of these applications are discussed, pointing out the need for better cooperation between manufacturers and users. The opinion is expressed that microwaves will eventually become a standard tool in the food industry for certain processing steps along a continuous production line where very rapid and uniform heating is required. However, it will be necessary, to a much larger extent than in the past, to adapt microwave heating equipment to the processes rather than to adapt the processes to standard microwave systems.