Department of Food Science and Technology, Faculty of Science, National University of Singapore, Singapore, Singapore.
Food Environ Virol. 2021 Mar;13(1):74-83. doi: 10.1007/s12560-020-09452-y. Epub 2021 Jan 15.
Hepatitis E virus (HEV) has been frequently detected from pork liver and liver products, which can usually cause self-limiting diseases in healthy adults, yet may result in fatality in immunosuppressed groups. Nevertheless, there is so far no standardized method for HEV detection available from pork liver and/or liver products. The present study aimed to optimize the virus extraction method of HEV from raw pork liver, which is often consumed in Asia undercooked to avoid a grainy texture. By comparing different sample preparation protocols and by applying the selected protocol to 60 samples collected from Singapore retail markets, we demonstrated that homogenization of 0.25 g raw pork liver with FastPrep™ Lysing Matrix Y containing yttria-stabilized zircondium oxide beads in 2 ml tubes and with harsh mechanical force at 6 ms, 40 s/cycle, for 5 cycles with 300 s pause time after each cycle is promising in both releasing the potentially intracellular viruses and resulting in satisfactory virus recovery rates (> 1%). A high prevalence (52%) of HEV genome was detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) from the 60 samples collected from Singapore retail markets imported from Indonesia, Australia and Malaysia. However, RNase treatment decreased the HEV prevalence to 33.3%, and all of the 20 positive samples were with high RT-qPCR Ct values above 35, suggesting that the positive RT-qPCR signals maybe largely due to the inactive viruses and/or exposed HEV RNA traces in raw pork liver products. Therefore, conscious care should be taken when interpreting molecular detection results of viruses from food samples to be correlated with public health risks.
戊型肝炎病毒（HEV）经常从猪肝和肝脏产品中检测到，在健康成年人中通常会引起自限性疾病，但在免疫抑制人群中可能导致死亡。然而，目前还没有标准化的方法可用于从猪肝和/或肝脏产品中检测 HEV。本研究旨在优化从生猪肝中提取 HEV 的病毒方法，因为亚洲人常将猪肝生吃以避免出现颗粒状质地。通过比较不同的样品制备方案，并将选定的方案应用于从新加坡零售市场收集的 60 个样本，我们证明了在 2ml 管中用 FastPrep™ Lysing Matrix Y （含氧化钇稳定氧化锆珠）将 0.25g 生猪肝匀浆，以 6ms、40s/循环、5 个循环的剧烈机械力处理，每个循环后有 300s 的暂停时间，对于释放潜在的细胞内病毒和获得令人满意的病毒回收率（>1%）都很有前景。通过从从新加坡零售市场从印度尼西亚、澳大利亚和马来西亚进口的 60 个样本中进行逆转录定量聚合酶链反应（RT-qPCR）检测，发现 HEV 基因组的高流行率（52%）。然而，RNase 处理将 HEV 的流行率降低至 33.3%，所有 20 个阳性样本的 RT-qPCR Ct 值均高于 35，表明阳性 RT-qPCR 信号主要归因于生猪肝产品中不活跃的病毒和/或暴露的 HEV RNA 痕迹。因此，在解释与公共健康风险相关的来自食品样本的病毒分子检测结果时，应谨慎对待。
