Abstract：
Fungal contaminations of cereal grains are a profound food-safety and food-security concern worldwide, threatening consumers\' and animals\' health and causing enormous economic burdens. Because far-ultraviolet C (far-UVC) light at 222 nm has recently been shown to be human-safe, we investigated its efficacy as an alternative to thermal, chemical, and conventional 254 nm UVC anti-fungal treatments. Our microplasma-based far-UVC lamp system achieved a 5.21-log reduction in the conidia of Aspergillus flavus suspended in buffer with a dose of 1032.0 mJ/cm2, and a 5.11-log reduction of Fusarium graminearum conidia in suspension with a dose of 619.2 mJ/cm2. We further observed that far-UVC treatments could induce fungal-cell apoptosis, alter mitochondrial membrane potential, lead to the accumulation of intracellular reactive oxygen species, cause lipid peroxidation, and result in cell-membrane damage. The lamp system also exhibited a potent ability to inhibit the mycelial growth of both A. flavus and F. graminearum. On potato dextrose agar plates, such growth was completely inhibited after doses of 576.0 mJ/cm2 and 460.8 mJ/cm2, respectively. To test our approach\'s efficacy at decontaminating actual cereal grains, we designed a cubical 3D treatment chamber fitted with six lamps. At a dose of 780.0 mJ/cm2 on each side, the chamber achieved a 1.88-log reduction of A. flavus on dried yellow corn kernels and a 1.11-log reduction of F. graminearum on wheat grains, without significant moisture loss to either cereal type (p > 0.05). The treatment did not cause significant changes in the propensity of wheat grains to germinate in the week following treatment (p > 0.05). However, it increased the germination propensity of corn kernels by more than 71% in the same timeframe (p < 0.05). Collectively, our results demonstrate that 222 nm far-UVC radiation can effectively inactivate fungal growth in liquid, on solid surfaces, and on cereal grains. If scalable, its emergence as a safe, cost-effective alternative tool for reducing fungi-related post-harvest cereal losses could have important positive implications for the fight against world hunger and food insecurity.
摘要：
谷物的真菌污染是全球范围内严重的食品安全和粮食安全问题，威胁消费者和动物的健康，造成巨大的经济负担。由于222nm的远紫外C（远UVC）光最近被证明对人类安全，我们研究了它作为热替代品的功效，化学,和常规254nmUVC抗真菌治疗。我们基于微等离子体的远UVC灯系统以1032.0mJ/cm2的剂量悬浮在缓冲液中的黄曲霉分生孢子减少了5.21-log，而以619.2mJ/cm2的剂量悬浮的镰刀菌分生孢子减少了5.11-log。我们进一步观察到远UVC处理可以诱导真菌细胞凋亡，改变线粒体膜电位，导致细胞内活性氧的积累，导致脂质过氧化，并导致细胞膜损伤。该灯系统还表现出抑制黄曲霉和禾谷草的菌丝体生长的有效能力。在马铃薯葡萄糖琼脂平板上，分别在576.0mJ/cm2和460.8mJ/cm2的剂量后，这种生长被完全抑制。为了测试我们的方法在净化实际谷物颗粒方面的功效，我们设计了一个装有六盏灯的立方体3D治疗室。每侧剂量为780.0mJ/cm2时，该室在干燥的黄色玉米粒上实现了黄曲霉的1.88对数减少，在小麦籽粒上实现了F.graminearum的1.11对数减少，两种谷物类型均无明显水分损失(p>0.05)。该处理在处理后一周内没有引起小麦籽粒发芽倾向的显著变化(p>0.05)。然而,在相同的时间范围内，它使玉米粒的发芽倾向增加了71％以上（p<0.05）。总的来说，我们的结果表明，222nm远UVC辐射可以有效灭活液体中的真菌生长，在固体表面上，和谷物。如果可扩展，它作为一个保险箱出现，减少与真菌有关的收获后谷物损失的具有成本效益的替代工具可能对消除世界饥饿和粮食不安全产生重要的积极影响。
