Post-Processing Temperature Rise in Foods: Conventional Hot Air and Microwave Ovens ¹

Measurement of temperature rise (N = 5 replications) in water (1000 ml), chicken frankfurters (46 ± 2 g/frankfurter) and cake cones (40 g/cone) after conventional hot air (160°C) and after microwave (2450 MHz; 50% and 100% power of 645 ± 25 W) processing indicated that temperature rise occurred more often in products heat-processed in microwave than in hot air ovens. Duration and extent of post-processing temperature rise (PPTR) in beef loaf patties (150 g/patty), pork and turkey roasts (approximately 2.3 kg/roast) and turkey casserole (0.9 kg/casserole) prepared in microwave ovens was quantified during three replications. Although present, PPTR should not change temperature objectives for domestic microwave processing of foods because of the extensive variability of duration and extent in PPTR within and among experimental products tested. However, PPTR should be given consideration when commercial products to be processed in microwave ovens and those used in mathematical modeling of microwave cooking/heating procedures are designed.