Researchers have begun extensive testing of the use of pulsed electric fields (PEFs) to control the number of harmful bacteria and other pathogens in milk and other food products that require pasteurization and sterilization to meet public health codes. While the idea of using high energy pulsed electrical fields to deactivate common pathogens is not entirely new, increased demand in less depleting methods of sterilization as well as a need for a backup plan to combat evolving and resistant pathogens is spurring the research to new levels that might introduce this as an accepted non-thermal process for certain preserved foods and milk products.

This new process for killing harmful bacteria and other microbes in milk and food products has come as something of a dual response to meet the increase in consumer demands for foods that are “closer to nature” and that contain the essential vitamins and nutrients found in the raw or unprocessed product. Since traditional thermal pasteurization and sterilization of milk and related food products both detracts from the fresh taste of many foods and also cuts down on the nutritional value, the promise of a non-thermal approach to pasteurization and food sterilization marks a promising and, as it appears at this early stage, healthier trend.

The study in question that examined the positive correlation between the use of pulsed electric fields to kill pathogens concerned itself mostly with milk, in part because this process is best for liquids and also because milk itself is one of the most potentially microbe-bearing in terms of commonly-consumed food items. While the study, which was based on the work of the study of pulsed electric fields (PEFs) that began as far back as the 1960s offered a positive outlook for the method, it was noted that due to the shifting nature of food-borne illnesses, using pulsed electric fields or PEFs will more likely be more of a backup method and additional process added to thermal pasteurization processes, especially since the PEF technique prolongs the pasteurized product’s shelf life by a short amount of time. As the study notes, “the epidemiology of food illnesses is rapidly changing as newly recognized pathogens emerge and well recognized pathogens increase in prevalence and virulence or become associated with new food vehicles” (Otunola et al 2008).

The study cited here examined, for the sake of simplicity of results and microbial complexity, E. Coli as the microbe to be tested against the high levels of electrical pulses. Tests revealed that this technique consistently delivered favorable results, however, the authors of the study were careful to note that pathogens such as these (among other potentially fatal ones found in milk and other common food products) have a marked ability to adapt to new stresses and become immune over a relatively short period of time.

While the processes involved with traditional thermal techniques such as pasteurization have served us well over the course of history, developing a secure and well-tested alternative and backup method of sterilizing milk and other preserved food products is essential. While this is not a viable alternative to pasteurization completely yet (and may never be, depending on the rapidly shifting state of pathogen resistance mechanisms among other things) further research into the science of pulsed electric fields (PEFs) and sterilization and preservation might offer us a future of healthier packaged and preserved foods as well as a more stable backup to traditional pasteurization processes using thermal as opposed to electrical energy.

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Source : Otunola, A., El-Hag, A., Jayaram, S., & Anderson, W. A. (2008). Effectiveness of Pulsed Electric Fields in Controlling Microbial Growth in Milk. International Journal of Food Engineering, 4(7), 1-15