Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Department of Clinical Laboratory, The Fifth Affiliated Hospital of Guangxi Medical University, Nanning, 530022, China.
Virol Sin. 2022 Dec;37(6):823-830. doi: 10.1016/j.virs.2022.10.007. Epub 2022 Oct 26.
The spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from cold-chain foods to frontline workers poses a serious public health threat during the current global pandemic. There is an urgent need to design concise approaches for effective virus inactivation under different physicochemical conditions to reduce the risk of contagion through viral contaminated surfaces of cold-chain foods. By employing a time course of electron beam exposure to a high titer of SARS-CoV-2 at cold-chain temperatures, a radiation dose of 2 kGy was demonstrated to reduce the viral titer from 10 to 0 median tissue culture infectious dose (TCID)/mL. Next, using human coronavirus OC43 (HCoV-OC43) as a suitable SARS-CoV-2 surrogate, 3 kGy of high-energy electron radiation was defined as the inactivation dose for a titer reduction of more than 4 log units on tested packaging materials. Furthermore, quantitative reverse transcription PCR (RT-qPCR) was used to test three viral genes, namely, E, N, and ORF1ab. There was a strong correlation between TCID and RT-qPCR for SARS-CoV-2 detection. However, RT-qPCR could not differentiate between the infectivity of the radiation-inactivated and nonirradiated control viruses. As the defined radiation dose for effective viral inactivation fell far below the upper safe dose limit for food processing, our results provide a basis for designing radiation-based approaches for the decontamination of SARS-CoV-2 in frozen food products. We further demonstrate that cell-based virus assays are essential to evaluate the SARS-CoV-2 inactivation efficiency for the decontaminating strategies.
新型冠状病毒（SARS-CoV-2）从冷链食品传播到一线工作人员，在当前全球大流行期间对公共卫生构成了严重威胁。迫切需要设计简洁的方法，在不同的物理化学条件下有效灭活病毒，以降低冷链食品污染表面病毒传播的风险。通过在冷链温度下对 SARS-CoV-2 的高滴度进行电子束照射的时间过程，证明辐照剂量为 2 kGy 可将病毒滴度从 10 降低至 0 中值组织培养感染剂量（TCID）/mL。接下来，使用人冠状病毒 OC43（HCoV-OC43）作为 SARS-CoV-2 的合适替代品，将 3 kGy 的高能电子辐射定义为对测试包装材料的滴度降低超过 4 个对数单位的灭活剂量。此外，定量逆转录聚合酶链反应（RT-qPCR）用于测试三种病毒基因，即 E、N 和 ORF1ab。TCID 与 SARS-CoV-2 检测的 RT-qPCR 之间存在很强的相关性。然而，RT-qPCR 无法区分辐射灭活和未辐照对照病毒的感染性。由于有效病毒灭活的定义辐射剂量远低于食品加工的安全上限，因此我们的结果为设计基于辐射的冷冻食品中 SARS-CoV-2 去污方法提供了依据。我们进一步证明，基于细胞的病毒检测对于评估去污策略中 SARS-CoV-2 的灭活效率至关重要。
