Preservation of liquid foods by high intensity pulsed electric fields - basic concepts for process design

In excess of a critical transmembrane potential Delta (rhoM) of -1 V produc ed by high intensity pulsed electric fields a rapid electrical breakdown an d local conformational changes of cell membranes occur which result in a dr astic increase in permeability and an equilibration of the electrochemical and electrical potential differences of the cell plasma and the extracellul ar medium. As irreverible membrane permeabilization impairs most vital phys iological control systems, high intensity pulsed electric fields may be app lied as a highly effective process for the microbial decontamination of liq uid foods. The efficiency of the treatment is largely, influenced by the in herent properties of the foods and of the spoiling microorganisms. In addit ion a number of technical limitations have to be considered. In this review an approach is presented which reduces the diversity of parameters that af fect microbial inactivation during pulsed power treatment, In particular, t he required total specific energy input is discussed. (C) 2001 Published by Elsevier Science Ltd.