Atmospheric pressure plasma and ultraviolet as a hurdle approach for table egg sanitization

This study investigates the use of novel waterless technologies, plasma and ultraviolet light (UV), to inactivate Salmonella on shell eggs as well as preserve the cuticle. Plasma is generated by applying electricity to air, and the reactive species produced can inactivate microorganisms in various environments. UV at 254 nm is known to have germicidal properties and is used in some commercial egg-washing processes as the final step after chemical washing. An increase in plasma treatment time from 1 min to 3 min increased reduction from 0.4 ± 0.8 to 2.2 ± 0.5 log for Salmonella Typhimurium spot inoculated on shell eggs. The UV treatment caused a reduction of 2.1 ± 1.0, 3.3 ± 0.1, and 3.7 ± 0.1 log at treatment times of 0.25, 1.5, and 3 min respectively. A reduction of 5.1 ± 0.3 log in Salmonella was obtained after plasma (3 min) + UV (3 min) treatment used in sequence as a hurdle approach. Plasma did not cause significant changes in color values but plasma + UV led to a significant increase in yellow color. There was no statistical difference in cuticle coverage between control, plasma, UV, and plasma + UV treatments. Various quality characteristics such as Haugh unit, egg weight, yolk index, yolk pH, albumen pH, yolk color, and shell strength did not show major changes during the 6-week storage study after all the treatments.