Evaluation of thermal death kinetic models of Salmonella Typhimurium ATCC 14028 and application for radio frequency pasteurization of shell eggs

Abstract

A thermal death time test heating block system (TDT-HBS) was employed to rapidly assess the thermal inactivation kinetic model parameters of S. typhimurium ATCC 14028. Subsequently, a radio frequency system was applied for pasteurization of S. typhimurium ATCC 14028 in shell eggs. The TDT-HBS treatment indicated that thermal inactivation kinetic models of S. typhimurium ATCC 14028 fitted the Weibull model well. Based on the model, it was estimated that a 5-log reduction should maintain temperatures at 54 °C for 442.5 min, 55 °C for 45.6 min, 56 °C for 33.2 min, 57 °C for 16.5 min, and 58 °C for 11.0 min, respectively. RF pasteurization protocol was developed by using an electrode gap of 9.0 cm, holding at 57 °C for 16.5 min, and finally achieved 4.95 ± 0.53 log reductions. Egg main quality had no significant (p > 0.05) difference after RF pasteurization. RF treatment holds potential as a novel pasteurization method to control Salmonella spp. in eggs.

Industry relevance

Most commercial eggs are unpasteurized in the worldwide during production, transportation, and consumption. The latest Salmonella spp. infection linked to Milo's Poultry Farms recalled eggs was identified by the Department of Health Services (DHS) on September 6, 2024. The general hot water immersion pasteurization process for in-shell eggs usually takes almost 60 min at 57 °C, that adds cost to the product and can damage the quality of eggs. The volumetric heating process induced by RF energy provides an alternative to inactivating Salmonella cells both surface and inside of the eggs and has minor effects on the main quality of eggs. RF protocol is a novel option as an effective pasteurization technology for the egg industry to provide high quality and safety eggs.