German Federal Institute for Risk Assessment, Department of Biological Safety, Diedersdorfer Weg 1, 12277 Berlin, Germany.
University of Leipzig, Institute for Food Hygiene, An den Tierkliniken 1, 04103 Leipzig, Germany.
Int J Food Microbiol. 2020 Jul 16;325:108625. doi: 10.1016/j.ijfoodmicro.2020.108625. Epub 2020 Apr 18.
Infection with the hepatitis E virus (HEV) can cause acute and chronic hepatitis in humans. The zoonotic HEV genotype 3 is mainly transmitted by consumption of raw and fermented meat products prepared from infected pigs or wild boars. Lowering of pH during fermentation is one of the microbiological hurdles considered to inhibit growth of certain pathogens. However, no data are currently available on pH stability of HEV. As a reliable and reproducible measurement of HEV infectivity in meat products is not established so far, the stability of the cell culture-adapted HEV genotype 3 strain 47832c was analyzed here in phosphate-buffered saline (PBS) at different pH values. Only a minimal decrease of infectivity (up to 0.6 log focus forming units) was found after treatment at pH 2 to 9 for 3 h at room temperature. At pH 10, a decrease of about 3 log was evident, whereas no remaining virus (>3.5 log decrease) was detected at pH 1. The conditions usually achieved during curing of raw sausages were simulated using D/L-lactic acid added to PBS resulting in pH 4.5 to 6.5. After incubation at 4 °C for 7 days at these conditions, no significant differences as compared to a standard PBS solution at pH 7.7 were evident. At room temperature, a 0.8 log decrease was found at pH 4.7 after 7 days incubation compared to pH 7.7, but less at the other pH values. In conclusion, only minimal inactivating effects were found at pH conditions commonly occurring during food processing. Therefore, remaining infectious virus might be present in fermented meat products if HEV-contaminated starting material was used. Additional effects of other factors like high salt concentrations and low a values should be investigated in future studies.
戊型肝炎病毒 (HEV) 感染可导致人类急性和慢性肝炎。人畜共患的 HEV 基因型 3 主要通过食用受感染的猪或野猪的生肉和发酵肉产品传播。发酵过程中 pH 值的降低是被认为抑制某些病原体生长的微生物障碍之一。然而，目前尚无关于 HEV 稳定性的数据。由于到目前为止还没有建立可靠且可重复的肉产品中 HEV 感染性的测量方法，因此，在这里分析了在磷酸盐缓冲盐水 (PBS) 中不同 pH 值下，细胞培养适应的 HEV 基因型 3 株 47832c 的稳定性。在室温下，用 pH 值为 2 到 9 的 PBS 处理 3 小时后，仅发现感染性有微小下降（最多下降 0.6 对数焦点形成单位）。在 pH 值为 10 时，下降幅度约为 3 对数，但在 pH 值为 1 时未检测到残留病毒（>3.5 对数下降）。使用添加到 PBS 中的 D/L-乳酸模拟生香肠腌制过程中通常达到的条件，导致 pH 值为 4.5 至 6.5。在这些条件下于 4°C 孵育 7 天后，与 pH 值为 7.7 的标准 PBS 溶液相比，没有明显差异。在室温下，与 pH 值为 7.7 相比，在 7 天孵育后 pH 值为 4.7 时发现下降了 0.8 对数，但在其他 pH 值下下降幅度较小。总之，在食品加工过程中通常出现的 pH 条件下，仅发现最小的失活作用。因此，如果使用受 HEV 污染的起始材料，发酵肉产品中可能存在传染性病毒。在未来的研究中，应进一步研究其他因素（如高盐浓度和低 a 值）的影响。
