Ye Mu, Li Xinhui, Kingsley David H, Jiang Xi, Chen Haiqiang
Department of Animal and Food Sciences, University of Delaware, Newark, Delaware, USA.
Appl Environ Microbiol. 2014 Apr;80(7):2248-53. doi: 10.1128/AEM.04260-13. Epub 2014 Jan 31.
Human norovirus (NoV) is the most frequent causative agent of food-borne disease associated with shellfish consumption. In this study, the effect of high hydrostatic pressure (HHP) on inactivation of NoV was determined. Genogroup I.1 (GI.1) or genogroup II.4 (GII.4) NoV was inoculated into oyster homogenates and treated at 300 to 600 MPa at 25, 6, and 1°C for 5 min. After HHP, samples were treated with RNase and viral particles were extracted with porcine gastric mucin (PGM)-conjugated magnetic beads (PGM-MBs). Viral RNA was then quantified by real-time reverse transcription (RT)-PCR. Since PGM contains histo-blood group-like antigens, which can act as receptors for NoV, deficiency for binding to PGM is an indication of loss of infectivity of NoV. After binding to PGM-MBs, RT-PCR-detectable NoV RNA in oysters was reduced by 0.4 to >4 log10 by HHP at 300 to 600 MPa. The GI.1 NoV was more resistant to HHP than the GII.4 NoV (P < 0.05). HHP at lower temperatures significantly enhanced the inactivation of NoV in oysters (P < 0.05). Pressure treatment was also conducted for clam homogenates. Treatment at 450 MPa at 1°C achieved a >4 log10 reduction of GI.1 NoV in both oyster and clam homogenates. It is therefore concluded that HHP could be applied as a potential intervention for inactivating NoV in raw shellfish. The method of pretreatment of samples with RNase, extraction of viral particles using PGM-MB binding, and quantification of viral RNA using RT-PCR can be explored as a practical means of distinguishing between infectious and noninfectious NoV.
人诺如病毒（NoV）是与食用贝类相关的食源性疾病最常见的病原体。在本研究中，测定了高静水压（HHP）对NoV灭活的影响。将基因组I.1（GI.1）或基因组II.4（GII.4）NoV接种到牡蛎匀浆中，并在25、6和1°C下于300至600 MPa处理5分钟。HHP处理后，样品用核糖核酸酶处理，病毒颗粒用猪胃粘蛋白（PGM）偶联磁珠（PGM-MBs）提取。然后通过实时逆转录（RT）-PCR对病毒RNA进行定量。由于PGM含有组织血型样抗原，可作为NoV的受体，与PGM结合能力的缺乏表明NoV感染性丧失。与PGM-MBs结合后，300至600 MPa的HHP使牡蛎中RT-PCR可检测到的NoV RNA减少0.4至>4个对数10。GI.1 NoV比GII.4 NoV对HHP更具抗性（P<0.05）。较低温度下的HHP显著增强了牡蛎中NoV的灭活效果（P<0.05）。还对蛤匀浆进行了压力处理。在1°C下450 MPa的处理使牡蛎和蛤匀浆中的GI.1 NoV减少>4个对数10。因此得出结论，HHP可作为灭活生贝类中NoV的一种潜在干预措施。用核糖核酸酶预处理样品、使用PGM-MB结合提取病毒颗粒以及使用RT-PCR定量病毒RNA的方法可作为区分感染性和非感染性NoV的一种实用手段进行探索。
