Department of Agricultural Biotechnology, Center for Food and Bioconvergence, Research Institute for Agricultural and Life Sciences, Seoul National University, Seoul, Republic of Korea.
Institutes of Green Bio Science & Technology, Seoul National University, Pyeongchang-gun, Gangwon-do, Republic of Korea.
Appl Environ Microbiol. 2019 May 30;85(12). doi: 10.1128/AEM.00006-19. Print 2019 Jun 15.
In this study, we developed a washing system capable of decontaminating fresh produce by combining the Spindle apparatus, which detaches microorganisms on sample surfaces, and a 222-nm krypton-chlorine excimer lamp (KrCl excilamp) (Sp-Ex) and investigated their decontamination effect against O157:H7, serovar Typhimurium, and on apple ( Borkh.) and bell pepper ( L.) surfaces. Initial levels of the three pathogens were approximately 10 CFU/sample. Both O157:H7 and Typhimurium were reduced to below the detection limit (2.0 log CFU/sample) after 5 and 7 min of treatment on apple and bell pepper surfaces, respectively. The amounts of on apple and bell pepper surfaces were reduced by 4.26 and 5.48 logs, respectively, after 7 min of treatment. The decontamination effect of the Sp-Ex was influenced by the hydrophobicity of the sample surface as well as the microbial cell surface, and the decontamination effect decreased as the two hydrophobicity values increased. To improve the decontamination effect of the Sp-Ex, Tween 20, a surfactant that weakens the hydrophobic interaction between the sample surface and pathogenic bacteria, was incorporated into Sp-Ex processing. It was found that its decontamination effect was significantly (0.05) increased by the addition of 0.1% Tween 20. Sp-Ex did not cause significant quality changes in apple or bell pepper surfaces during 7 days storage following treatment (0.05). Our results suggest that Sp-Ex could be applied as a system to control pathogens in place of chemical sanitizer washing by the fresh-produce industry. Although most fresh-produce processing currently controls pathogens by means of washing with sanitizers, there are still problems such as the generation of harmful substances and changes in product quality. A combination system composed of the Spindle and a 222-nm KrCl excilamp (Sp-Ex) developed in this study reduced pathogens on apple and bell pepper surfaces using sanitizer-free water without altering produce color and texture. This study demonstrates the potential of the Sp-Ex to replace conventional washing with sanitizers, and it can be used as baseline data for practical application by industry. In addition, implementation of the Sp-Ex developed in this study is expected not only to meet consumer preference for fresh, minimally processed produce but also to reduce human exposure to harmful chemicals while being beneficial to the environment.
在这项研究中，我们开发了一种清洗系统，该系统结合了 spindle 装置（可分离样品表面上的微生物）和 222nm 氪-氯准分子灯（KrCl excilamp）（Sp-Ex），研究了它们对苹果（Borkh.）和甜椒（L.）表面上 O157:H7、鼠伤寒沙门氏菌和的去污效果。三种病原体的初始水平约为 10 CFU/样品。在苹果和甜椒表面上分别处理 5 和 7 分钟后，O157:H7 和鼠伤寒沙门氏菌均减少到检测限以下（2.0 log CFU/样品）。处理 7 分钟后，苹果和甜椒表面上的数量分别减少了 4.26 和 5.48 个对数。Sp-Ex 的去污效果受样品表面疏水性和微生物细胞表面疏水性的影响，随着两种疏水性值的增加，去污效果降低。为了提高 Sp-Ex 的去污效果，将表面活性剂吐温 20 加入 Sp-Ex 处理中，该表面活性剂可减弱样品表面与致病菌之间的疏水相互作用。结果发现，加入 0.1%吐温 20 可显著（0.05）提高其去污效果。Sp-Ex 处理后，在 7 天的贮藏期内，苹果和甜椒表面的质量没有发生显著变化（0.05）。我们的结果表明，Sp-Ex 可作为一种替代新鲜农产品行业化学消毒剂清洗的系统来控制病原体。尽管目前大多数新鲜农产品加工都是通过使用消毒剂清洗来控制病原体，但仍然存在产生有害物质和改变产品质量等问题。本研究中开发的由 spindle 和 222nm KrCl excilamp 组成的组合系统（Sp-Ex）使用不含消毒剂的水在不改变产品颜色和质地的情况下减少了苹果和甜椒表面的病原体。本研究表明，Sp-Ex 有潜力替代传统的消毒剂清洗，可为行业实际应用提供基础数据。此外，实施本研究中开发的 Sp-Ex 不仅有望满足消费者对新鲜、低加工农产品的偏好，还可以减少人类接触有害化学品的机会，同时有利于环境。
