Liquid Food Pasteurization by Pulsed Electric Fields

Traditional thermal pasteurization is an efficient and robust method to inactivate micro-organisms and enzymes in food products; however it also affects the fresh characteristics and heat-labile components of the product. Pulsed electric field (PEF) is based on the electroporation of bacteria and other cells and can be used as alternative, non-thermal pasteurization method for high valuable liquid products as it avoids extensive heating and therefore better retains the product quality. In this chapter, the use of PEF (E = 10–40 kV/cm, τ = 1–100μs, w = 50–8000 kJ/kg) combined with low to moderate heat (T < 60 °C) as method for pasteurization is described. The possibilities and constraints to apply this PEF process for different liquid food categories are discussed, including fruit juices, smoothies, fruit purees, milk and milk-derived products, eggs, and beer. These different food categories are typified by specific product characteristics, i.e. pH, viscosity, conductivity, and presence of protein, fat or dissolved gas, which influence the efficiency and applicability of the PEF treatment. Essential for the application of PEF for pasteurization is that a safe food product will be obtained and that the PEF treatment brings added value with respect to shelf life and product quality compared to a conventional thermal treatment.