Low-Temperature Pasteurization of Liquid Whole Egg using Intense Pulsed Electric Fields

This paper describes the pasteurization of liquid whole egg (LWE) using intense pulsed electric fields (PEF) combined with mild heat. Four kinds of liquids as solvents including carboxymethyl cellulose (CMC) solution, CMC solution with adding lipoproteins extracted from LWE (CMC+), LWE, and centrifuged LWE for reducing lipoproteins (LWE-) were compared for the effectiveness of the PEF pasteurization. The liquids including Enterobacter aerogenes (10(7) /mL) were subjected to a number of PEF with an amplitude of 30kV/cm or 50kV/cm. Pre- and post-PEF thermal treatments with a temperature below 55 degrees C were used to enhance the killing effect. Our experiments show that the bacteria logarithmic reduction ratio of the pasteurization using 30kV/cm PEF for CMC, CMC+, LWE, and LWE- were 6.6, 2.4, 1.4, and 1.6, respectively, whereas the reduction ratios were all more than 6 when the increased field of 50 kV/cm. Only bacteria in CMC solution were effectively killed compared to other liquids, which include lipoproteins, more or less. Numerical analysis of the electric field indicates the presence of lipoproteins in the vicinity of bacteria lessens the bacterial membrane potential, which results in weakening the killing effect. (C) 2017 Wiley Periodicals, Inc.