17 - Pasteurization of milk with pulsed electric fields

Abstract

Pulsed electric fields (PEF) is a novel and very promising technology for pasteurization of pumpable foods. The food enters the PEF chamber, flows between two electrodes, and undergoes pulsing by electric fields. Microorganisms present in the food are inactivated as a result. There are theories regarding the mechanism of this inactivation. One of the most studied theories is related to electroporation of cell membranes. PEF treatment times are very short (microseconds), and processing temperatures are near room temperature or below, the main reason why PEF is called a nonthermal technology. Due to PEF’s short processing times and low temperatures, foods keep their original sensorial and nutritional characteristics after processing. The effectiveness of PEF to inactivate bacteria and extend the shelf-life of food also ensures the microbiological quality of the final product. Energy savings using PEF are also important compared with conventional thermal treatment. This chapter presents the basic principles of PEF technology with special focus on its use in processing milk. Microbiological and enzymatic studies are mentioned as well. The advantages of this technology and current challenges and limitations are discussed throughout the chapter.