Mathematical modeling of ohmic heating of two-component foods with non-uniform electric properties at high frequencies

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.

Identification of spoilage microorganisms in blueberry juice and their inactivation by a microchip pulsed electric field system

Blueberry juice is a healthy and nutritious food that has become increasingly popular worldwide. However, little is known about the microbial groups of this juice that can cause its spoilage. This study aimed to identify the main spoilage microorganisms in blueberry juice and explore whether a microchip pulsed electric field (MPEF) can effectively inactivate them. We performed polymerase chain reaction (PCR) amplification, as well as 16S rDNA, 18S rDNA, internal transcribed spacer (ITS), and 26S rDNA gene sequence analyses. Nine species belonging to eight genera, including Pantoea, Burkholderia, Pichia, Meyerozyma, Cryptococcus, Aureobasidium, Cladosporium, and Penicillium were identified as spoilage microorganisms. Cryptococcus sp., Meyerozyma sp., and Pichia sp. were specific spoilage organisms (SSO) owing to their rising numbers throughout spoilage progression. The effect of MPEF on the potential inactivation of these microorganisms was to induce significant inactivation of viable Cryptococcus sp., Meyerozyma sp., and Pichia sp. This research provides a theoretical basis for the application of MPEF in improving the quality of blueberry juice.