# Non-Thermal and Mild Thermal Technologies for Table Egg Shell Surface Decontamination: Microbial Efficacy, Egg Quality, and Industrial Considerations

## TL;DR

This paper reviews non-thermal and mild thermal methods to decontaminate egg shells, focusing on their effectiveness, impact on egg quality, and industrial feasibility.

## Contribution

The paper provides a comprehensive review of non-thermal and mild thermal decontamination technologies for table eggs, highlighting their microbial efficacy and industrial constraints.

## Key findings

- Non-thermal technologies like UV-C and ozone can reduce microbial loads on eggshells without significant damage to egg quality.
- Industrial factors such as treatment uniformity and line speed affect the real-world performance of these decontamination methods.
- These technologies cannot inactivate pathogens that have penetrated shell membranes, emphasizing the need for targeted application.

## Abstract

Microbial contamination of table eggs remains an important food safety concern, largely due to the presence of Salmonella spp. on eggshell surfaces and the potential for cross-contamination along the collection, grading, and packing chain. Conventional sanitation practices, including chlorinated-water washing, can reduce surface microbial loads but may also present limitations related to cuticle alteration, process variability, water use, and the risk of recontamination when operational conditions are not tightly controlled. This review synthesizes evidence on non-thermal and selected mild thermal technologies for the surface decontamination of intact table eggs, including ultraviolet-C (UV-C) irradiation, pulsed light, ozone-based treatments (gas and microbubble systems), non-thermal plasma, plasma-activated water, and gas-phase hydroxyl radical processes. For each approach, antimicrobial performance is discussed alongside effects on eggshell integrity, cuticle preservation, and key quality indicators (e.g., Haugh unit, albumen pH, yolk color, and shell strength). Particular attention is given to industrial constraints that influence real-world performance, such as treatment uniformity and shading effects, humidity dependence, line speed, equipment integration, and validation criteria. A shared limitation of surface treatments is their inability to inactivate pathogens that have penetrated shell membranes or contaminated egg contents, underscoring the need to align technology selection with the targeted hazard and the regulatory context. Thus, available data indicate that non-thermal technologies can contribute to reducing eggshell contamination when properly optimized, although broader implementation will depend on standardized operating parameters, robust process validation, and regulatory acceptance within existing egg processing systems.