ABSTRACT
The basic goal of food preservation technologies is to provide safer food products with extended shelf life and inactivation of microorganisms or inhibition of microbial growth. In order to inactivate microorganisms or prevent microbial growth, different preservation methods such as application of low or high temperature, reduction of water activity, addition of preservatives, lowering pH, and modication of the gas atmosphere in food packaging or the environment are applied (Blackburn and McClure, 2002; Mohamed and Eissa, 2012). In most of the cases, the applied dose or magnitude of these technologies should be very high to inactivate some microorganisms, which adversely affect the desired sensory and nutritional properties of foods. Therefore, alternative or new technologies are in search for product commodities having the required level of microbial inactivation and good quality as well as better sensory characteristics. A new technology should have signicant impact on food quality, while at the same time maintain the cost of technology within feasibility limits in order to be qualied as an alternative method (Lado and Yousef, 2002; Mohamed and Eissa, 2012). Several technologies based on the application of different forms of energy or physical force such as pulsed electric eld (PEF), high hydrostatic pressure
16.1 PEF Technology and Denition ..................................................................... 393 16.2 PEF-Processing Systems ................................................................................ 395 16.3 Inactivation Mechanisms of Bacteria and Enzymes ...................................... 398
16.3.1 Microbial and Enzyme Inactivation by PEF Processing ...................402 16.3.1.1 Inactivation of Microorganisms .........................................402 16.3.1.2 Inactivation of Enzymes .................................................... 422
16.4 PEF Effects on Nutritional and Sensory Properties and Bioactive Components .................................................................................................... 422
16.5 Food Safety Issues of PEF-Processed Foods ................................................. 430 16.6 Packaging of PEF-Processed Foods .............................................................. 432 16.7 Future Trends ................................................................................................. 433 References ................................................................................................................ 434
(HHP), ohmic heating, microwave, cold plasma, etc., have been developed that have the capability of inactivating microorganisms at lower temperatures than typically used in conventional heat treatments (Lado and Yousef, 2002; Mohamed and Eissa, 2012). Among the new technologies classied, nonthermal processes have gained importance in recent years due to the increasing demand for foods with a high nutritional value and fresh-like characteristics, representing an alternative to conventional thermal treatments, and PEF is an emerging technology that has been extensively studied for nonthermal food processing, especially for low-viscosity, high-acidity foods such as fruit juices and beverages and to lesser extent for milk (Garde-Cerdan et al., 1997; Reina et al., 1998; Evrendilek et al., 2004a), yogurt drink (Evrendilek et al., 2004b), yogurt-based products (Yeom et al., 2004), apple sauce, salad dressing, soup (Vega-Mercado et al., 1996a,b; Mohamed and Eissa, 2012), liquid whole egg (LWE), and liquid egg products (Martin-Belloso et al., 1997; Mohamed and Eissa, 2012; Hermawan et al., 2004).
