Application of ohmic heating for the inactivation of microbiological hazards in food products

Ohmic heating has long been used to inactivate pathogens in food products. Several research investigations on the use of ohmic heating technology in the inactivation of microbial hazards in food products are discussed in this review. These studies are discussed under the following sub-headings: (a) inactivation of microbiological hazards, (b) in combination treatments with other sanitizing technologies, and (c) mathematical modeling, all of which are of long-standing interest. In this review, we evaluate ohmic heating as a rapid and volumetric heating process that inactivates microbiological hazards in food products. We also examine ohmic heating-based combination treatments as promising methods to maximize microbial inactivation efficacy and minimize the quality deterioration of food products. We first highlight the fact that most researchers had an interest in the inactivation of vegetative pathogens, whereas only a few focused on the inactivation of bacterial spores. In general, significantly higher treatment conditions were needed to inactivate bacterial spores (>95°C) than vegetative pathogens (>50°C). Studies on the inactivation of viral pathogens by ohmic heating are limited, and further research is needed in this field. In the first part of this review, the nonthermal effects of ohmic heating are also discussed, which is a popular topic in the food industry. Cumulatively, research suggests that that these nonthermal effects are dependent on the treatment conditions and the electrical conductivity of different food samples. Therefore, we suggest that focus should be on the thermal rather than the nonthermal effects of ohmic heating when considering the application of this technology to inactivate pathogens. Finally, we introduced combination technology based on ohmic heating and mathematical modeling, which are of interest recently.