Electroporation of Cell Membranes: The Fundamental Effects of Pulsed Electric Fields in Food Processing

Using of pulsed electric fields (PEF) for killing of microorganisms in liquid foods is a promising new non-thermal food processing and preservation technology. However, to implement and optimize this technology, a good understanding of the actual mechanisms that govern microbial inactivation by this technique is required. Here, fundamentals of cell electroporation, which is considered as underlying phenomenon of food processing technology, are discussed. The whole process of the cell electroporation (food processing) by PEF is divided into the following four main stages: (1) building the transmembrane potential up by the applied external electric field, (2) creation of small metastable hydrophilic pores, when the transmembrane potential has been built up; (3) evolution of the pore population-the change in the number and/or sizes of pores-during an electric treatment; and (4) post-treatment stage consisting of the processes that take place after the electric treatment (leakage of intracellular compounds, pore shrinkage and disappearance, etc.). The current knowledge of the processes taking place during each of the above stages as well as the factors influencing them is discussed. Theoretical considerations are illustrated with the experimental data available.