Combination of pulsed electric fields, mild heat and essential oils as an alternative to the ultrapasteurization of liquid whole egg

The production of microbiologically safe liquid whole egg (LWE) by industrial ultrapasteurization is restricted by the high thermal sensitivity of LWE components. This research proposes an alternative treatment based on the application of pulsed electric fields (PEF) and mild heat, in the presence of natural essential oils (EOs) or their individual components (ICs). The obtained results indicate that the successive application of PEF (25 kV/ and 100 kJ/kg) followed by heat (60 °C during 3.5ʹ) to LWE added with 200 μL/L of lemon EO would reach 4 log10 cycles of inactivation of Salmonella Senftenberg 775 W and Listeria monocytogenes, when any of these barriers acting alone inactivated less than 1.5 log10 cycles of either bacteria. Therefore, the synergism between lemon EO and the successive application of PEF and heat would provide a safety level similar to that of ultrapasteurization treatment for Salmonella Senftenberg 775 W and L. monocytogenes, but at a lower temperature. To a lesser extent, synergism with the successive application of PEF and heat was also observed in the presence of 200 μL/L of carvacrol, citral, (+)-limonene, or mandarin EO, reaching about 3.5 log10 cycles of inactivation in Salmonella Senftenberg and 3.0 log10 cycles in L. monocytogenes, respectively. A sensory test on LWE containing 200 μL/L of each additive in the form of omelets and sponge cakes revealed that this concentration of mandarin EO, lemon EO, or (+)-limonene did not decrease the sensory acceptability of the LWE-containing products, and lemon EO and mandarin EO even increased the hedonic acceptability of sponge cakes. In conclusion, this process could be applied in the food industry to obtain microbiologically safe LWE, which could be used to produce egg-based products without decreasing (and even increasing) their sensory appeal.