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.

本研究旨在探讨新型无水技术——等离子体及紫外光（UV）在壳蛋上灭活沙门氏菌并保持蛋壳表面角质层完整性的应用。等离子体通过向空气中施加电流产生，其生成的活性物种能够在多种环境中灭活微生物。已知254 nm波长的紫外光具有杀菌特性，并在某些商业蛋清洗过程中作为化学清洗后的最终步骤。将等离子体处理时间从1分钟延长至3分钟，对壳蛋上接种的沙门氏菌泰姆鲁菌的灭活效果从0.4 ± 0.8对数值降至2.2 ± 0.5对数值。紫外光处理在0.25、1.5和3分钟的处理时间下分别导致2.1 ± 1.0、3.3 ± 0.1和3.7 ± 0.1对数值的减少。采用等离子体（3分钟）+ 紫外光（3分钟）连续处理的障碍策略，获得了5.1 ± 0.3对数值的沙门氏菌减少。等离子体处理并未引起颜色值显著变化，而等离子体+紫外光处理则导致黄色显著增加。在控制组、等离子体处理组、紫外光处理组和等离子体+紫外光处理组之间，角质层覆盖率无显著差异。在所有处理完成后，6周储存研究期间，各种质量特性如Haugh单位、蛋重、蛋黄指数、蛋黄pH值、蛋白pH值、蛋黄颜色和蛋壳强度等均未出现重大变化。