US Food and Drug Administration, National Center for Food Safety and Technology, 6502 S Archer Road, Summit-Argo, IL 60501, USA.
Food Microbiol. 2011 Aug;28(5):998-1002. doi: 10.1016/j.fm.2011.01.011. Epub 2011 Feb 3.
Preserving fruits and vegetables by dehydration is common; however, information is limited concerning viral survival on the produce during the process. This work demonstrated the effects of low heat dehydration on inactivating hepatitis A virus (HAV) on contaminated green onions. Inoculated and uninoculated onion samples were dehydrated at target temperatures of 45-65 °C for 20 h. HAV from artificially contaminated onions (fresh or dehydrated) was eluted by shaking at 145 rpm at 20 °C for 20 min with 3% beef extract, pH 8, and followed by 0.2 μM-membrane filtration before plaque assay and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analysis. Dilutions of the filtrates were made for obtaining countable plaques on FRhK-4 cell monolayers in 6-well plates, and also for eliminating inhibitors in qRT-PCR. Average water activity of the onions after 20 h-dehydration was 0.227, regardless of temperature used (47.9 °C or 65.1 °C). Eight dehydration trials resulted in a linear relationship between HAV inactivation and dehydration temperature, with HAV log reduction = 0.1372x(°C) - 5.5572, r(2) = 0.88. Therefore, the 20 h-heating at 47.8, 55.1, and 62.4 °C reduced infectious HAV in onions by 1, 2, and 3 logs respectively, the Z value being 7.3 °C. It was concluded that low heat dehydration using 62.5 °C or above could effectively inactivate HAV on contaminated onions by >3 logs.
脱水保存水果和蔬菜很常见；然而，关于病毒在生产过程中在农产品上存活的信息有限。本研究旨在研究低热脱水对污染的绿洋葱上甲型肝炎病毒（HAV）失活的影响。将接种和未接种的洋葱样品在目标温度为 45-65°C 下干燥 20 小时。用 3%牛肉浸膏（pH8）以 145rpm 摇床在 20°C 下洗脱来自人工污染洋葱（新鲜或干燥）的 HAV，然后用 0.2μM 膜过滤，进行噬斑试验和定量逆转录-聚合酶链反应（qRT-PCR）分析。用滤出液稀释，在 FRhK-4 细胞单层上获得 6 孔板中的可计数噬斑，并用 qRT-PCR 消除抑制剂。无论使用的温度（47.9°C 或 65.1°C）如何，经过 20 小时干燥后，洋葱的平均水活度为 0.227。8 次干燥试验结果表明，HAV 失活与干燥温度呈线性关系，HAV 对数减少=0.1372x（°C）-5.5572，r（2）=0.88。因此，在 47.8、55.1 和 62.4°C 下加热 20 小时，分别使洋葱中传染性 HAV 减少 1、2 和 3 个对数，Z 值为 7.3°C。结论是，使用 62.5°C 或更高的低热脱水可以有效使污染洋葱上的 HAV 减少>3 个对数。
