Development of a dual cylindrical microwave and ohmic combination heater for minimization of thermal lags in the processing of particulate foods

Continuous flow microwave heating and sterilization for liquid food

Continuous flow microwave sterilization for liquid food has advantages of a short time and high retention rate of nutrients. However, uneven microwave heating is the critical factor restricting the industrialization of microwave sterilization. This paper reviews the up-to-date research on the continuous flow microwave heating and the continuous flow microwave sterilization system for liquid food. The causes of the non-uniformity of continuous flow microwave heating are thoroughly discussed and the methods of improving the uniformity are proposed. Finally, the recommendations for future research of continuous flow microwave sterilization for liquid food are presented.

Comparative study of survival of Escherichia coli O157:H7 inoculated in pork batter after ohmic cooking and water bath cooking

In this study, the effects of ohmic cooking (OH) and water bath cooking (WB) on the reduction of Escherichia coli O157:H7 inoculated in pork batter with addition of sodium chloride (NaCl) were studied, and the recovery and growth of OH and WB treated E. coli O157:H7 were also investigated during storage. The time for samples cooked by OH to reach the targeted endpoint temperature (61, 65, and 72 °C) was shorter than that of WB, and the addition of NaCl dramatically shortened the cooking time of OH treated samples, however, no significant effect was observed by WB. Samples with NaCl and cooked by OH had lower cooking loss than that of WB, but the inactivation effect of E. coli O157:H7 by OH was comparable to WB. During storage, the recovery and growth of sublethally injured E. coli O157:H7 were slower at 4 °C, and storage at 4 °C for 24 h delayed their recovery at 37 °C from 36 h to 48 h. These results indicated that OH had greater potential in the application of meat batter processing.

Inactivation of Microorganisms in Foods by Ohmic Heating: A Review

Ohmic heating (OH) is an alternative food processing technology for effectively inactivating microorganisms that depends on the heat that has been generated when electrical current passes directly through food material. The advantages of OH for microbial inactivation include shorter heating time, more uniform heat distribution inside food, reduced nutrition losses, and higher energy efficiency. This review presents some published information regarding the inactivation of microorganisms by OH, including the major factors that influence the inactivation effectiveness of OH, the inactivation of vegetative cells and spores in foods by OH, the inactivation mechanisms of OH, and the challenges and prospects of OH for food processing. This information will improve the understanding of OH for inactivation of microorganisms and promote the application of OH in the food industry.