This study compared the inactivation efficacy and performance of UV-LEDs emitting at 259, 268, 275, 289, and 370 nm against a low pressure mercury lamp at 253.7 nm for the foodborne pathogens, E. coli, Listeria and Salmonella. Action spectra were determined for three pathogenic and three non-pathogenic strains and compared with UV absorbance of their bacterial DNA. The lethality of UV wavelengths correlated with bacterial DNA absorbance. At an equivalent UV dose (7 mJ·cm⁻²), UV-LEDs emitting at 259 and 268 nm achieved the highest log count reductions out of the tested wavelengths. Refrigeration (4 °C) increased irradiance of the 268 nm UV-LEDs while not affecting reduction of Listeria compared to 25°C. Combining 259 and 289 nm UV-LED wavelengths at an equivalent UV dose had a synergistic effect on reduction of E. coli and Listeria, yielding a 1.2 and 0.6 log higher reduction, respectively, than the expected additive effect.

Industrial relevance

UV-LED treatment at 259, 268, and 275 nm can either equal or, in most cases, surpass the inactivation efficacy of traditional LPM lamps at 253.7 nm. Further, the determined action spectra can be used to identify the optimum inactivation wavelength for common foodborne pathogens and hence increase processing efficiency. In some cases, inactivation efficacy can be improved by combining UV wavelengths in order to achieve a synergistic effect. The effectiveness of UV-LED treatment at refrigeration temperatures validates their use in cold environments. Overall, UV-LEDs have strong potential within the food industry due to their advantages and possibilities for incorporation into a wide variety of treatment systems.

中文翻译：

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单波长和多波长紫外发光二极管灭活大肠杆菌，李斯特菌和沙门氏菌

这项研究比较了在259、268、275、289和370 nm处发射的UV-LED与食源性病原体E的253.7 nm低压汞灯的灭活功效和性能。大肠杆菌，李斯特菌和沙门氏菌。确定了三个致病菌株和三个非致病菌株的作用谱，并将其与细菌DNA的紫外线吸收率进行了比较。紫外线波长的致死性与细菌DNA的吸收有关。在等效紫外线剂量（7 mJ·cm ^-2）下，在259和268 nm处发射的UV-LED在测试波长范围内实现了最高的对数计数减少。冷藏（4°C）增加了268 nm UV-LED的辐照度，同时不影响李斯特菌的减少与25°C相比。以相等的紫外线剂量组合259和289 nm的UV-LED波长对E的降低具有协同作用。大肠埃希菌和李斯特菌的减少分别比预期的加和效应高1.2和0.6个对数。

行业相关性

在259、268和275 nm处进行UV-LED处理可以等于或在大多数情况下超过253.7 nm处传统LPM灯的灭活效果。此外，确定的作用谱可用于识别常见食源性病原体的最佳灭活波长，从而提高加工效率。在某些情况下，可以通过组合紫外线波长来提高灭活功效，以达到协同作用。在制冷温度下进行UV-LED处理的有效性验证了它们在寒冷环境中的使用。总体而言，UV-LED的优势和可能将其纳入多种处理系统中，因此在食品工业中具有强大的潜力。