Nyhan Laura, Przyjalgowski Milosz, Lewis Liam, Begley Máire, Callanan Michael
Department of Biological Sciences, Munster Technological University, T12 P928 Cork, Ireland.
Centre for Advanced Photonics and Process Analysis, Munster Technological University, T12 P928 Cork, Ireland.
Foods. 2021 Apr 8;10(4):797. doi: 10.3390/foods10040797.
The addition of contaminated powdered spices and seasonings to finished products which do not undergo further processing represents a significant concern for food manufacturers. To reduce the incidence of bacterial contamination, seasoning ingredients should be subjected to a decontamination process. Ultraviolet light emitting diodes (UV-LEDs) have been suggested as an alternative to UV lamps for reducing the microbial load of foods, due to their increasing efficiency, robustness and decreasing cost. In this study, we investigated the efficacy of UV-LED devices for the inactivation of four bacteria ( Typhimurium) on a plastic surface and in four powdered seasoning ingredients (onion powder, garlic powder, cheese and onion powder and chilli powder). Surface inactivation experiments with UV mercury lamps, UVC-LEDs and UVA-LEDs emitting at wavelengths of 254 nm, 270 nm and 365 nm, respectively, revealed that treatment with UVC-LEDs were comparable to, or better than those observed using the mercury lamp. Bacterial reductions in the seasoning powders with UVC-LEDs were less than in the surface inactivation experiments, but significant reductions of 0.75-3 log colony forming units (CFU) were obtained following longer (40 s) UVC-LED exposure times. Inactivation kinetics were generally nonlinear, and a comparison of the predictive models highlighted that microbial inactivation was dependent on the combination of powder and microorganism. This study is the first to report on the efficacy of UV-LEDs for the inactivation of several different bacterial species in a variety of powdered ingredients, highlighting the potential of the technology as an alternative to the traditional UV lamps used in the food industry.
对于食品制造商而言，在未经进一步加工的成品中添加受污染的粉末状香料和调味料是一个重大问题。为了降低细菌污染的发生率，调味成分应进行去污处理。由于紫外线发光二极管（UV-LED）效率不断提高、性能更稳定且成本不断降低，有人建议用其替代紫外线灯来降低食品的微生物负荷。在本研究中，我们调查了UV-LED装置对塑料表面以及四种粉末状调味料（洋葱粉、大蒜粉、芝士洋葱粉和辣椒粉）中四种细菌（鼠伤寒沙门氏菌）的灭活效果。分别使用波长为254 nm、270 nm和365 nm的紫外线汞灯、UVC-LED和UVA-LED进行表面灭活实验，结果显示，UVC-LED处理效果与汞灯相当，甚至更好。UVC-LED对调味粉中细菌的减少效果低于表面灭活实验，但在较长的（40秒）UVC-LED照射时间后，细菌数量显著减少了0.75 - 3个对数菌落形成单位（CFU）。灭活动力学通常是非线性的，预测模型的比较突出表明微生物灭活取决于粉末和微生物的组合。本研究首次报道了UV-LED对多种粉末状成分中几种不同细菌物种的灭活效果，突出了该技术作为食品工业中传统紫外线灯替代品的潜力。
