Application of electron beam to inactivate Salmonella in food: Recent developments

Food is a transmission vehicle for Salmonella that causes about 96% of all salmonellosis cases. The high frequency and incidence of foodborne outbreaks makes Salmonella a significant public health concern and economic burden worldwide. Although thermal pasteurization is commonly applied to food products to inactivate Salmonella, heat simply cannot be used for fresh food products such as produce, eggs, and many ready-to-eat (RTE) foods. It has also been demonstrated that Salmonella can survive thermal pasteurization in peanut butter. Besides an on-going concern with Salmonella in eggs, the recent outbreaks in fresh produce and peanut butter clearly indicate a need for non-thermal technologies to adequately inactivate this pathogen.Electron beam (e-beam) uses linear accelerator to accelerate electrons from electricity to near-speed-of-light. As with other types of ionizing radiation, e-beam inactivates microorganisms directly by DNA damage resulting in reproductive death and indirectly by free radicals generated during water radiolysis that disintegrate cell membrane. Since e-beam inactivates microorganisms non-thermally, it may be used to inactivate Salmonella in fresh food products such as produce, eggs, RTEs, and peanut butter. A new development is secondary emission electron gun (SEEG) e-beam. This compact SEEG e-beam has a potential to be incorporated into a microwave oven. This incorporation would allow non-thermal inactivation of foodborne pathogens including Salmonella at the point-of-consumption (i.e., household level and food service).This article reviews the application of e-beam to inactivate Salmonella in various food matrices with an emphasis on most recent Salmonella outbreaks. The article also succinctly reviews the latest understanding of the mechanism of microbial inactivation by e-beam and radio-resistance as well as microbial inactivation kinetics.