Shell egg pasteurization using radio frequency in combination with hot air or hot water

Area of Science:

• Food Science
• Microbiology
• Agricultural Engineering

Background:

• Shell eggs are a significant source of Salmonella Typhimurium contamination.
• Thermal pasteurization methods are crucial for ensuring shell egg safety.
• Radio frequency (RF) heating offers potential for rapid and uniform heating.

Purpose of the Study:

• To evaluate the efficacy of hot air (HA), hot water immersion (HWI), and hot water spraying (HWS) alone and with radio frequency (RF) for Salmonella Typhimurium inactivation in shell eggs.
• To assess the impact of these treatments on egg physical quality and angel food cake production.
• To determine optimal pasteurization parameters for shell eggs.

Main Methods:

• Shell eggs were subjected to three thermal treatments: hot air (HA), hot water immersion (HWI), and hot water spraying (HWS).
• Treatments were applied alone and in combination with radio frequency (RF) pre-treatment.
• Salmonella Typhimurium inactivation, physical egg quality (yolk index, Haugh unit, albumen turbidity), and angel food cake quality were evaluated.

Main Results:

• Hot water immersion (HWI) and hot water spraying (HWS) were more effective than hot air (HA) for pasteurization.
• Radio frequency pre-treatment significantly reduced pasteurization times for both RF/HWI (19.5 min) and RF/HWS (24.5 min) to achieve a 5-log reduction of S. Typhimurium.
• Egg quality was largely maintained, with some changes in Haugh unit and albumen turbidity; cake-making ability was preserved with extended whipping times.

Conclusions:

• Combined radio frequency and hot water spraying (RF/HWS) is a viable and effective alternative to RF/HWI for shell egg pasteurization.
• Both RF/HWS and RF/HWI treatments achieve significant microbial reduction without compromising essential egg quality attributes.
• HWS and HWI can be effectively utilized as the secondary step in radio frequency pasteurization of shell eggs.