Baert Leen, Uyttendaele Mieke, Vermeersch Mattias, Van Coillie Els, Debevere Johan
Department of Food Safety and Food Quality, Laboratory of Food Microbiology and Food Preservation, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
J Food Prot. 2008 Aug;71(8):1590-7. doi: 10.4315/0362-028x-71.8.1590.
The reduction of murine norovirus 1 (MNV-1) on onions and spinach by washing was investigated as was the risk of contamination during the washing procedure. To decontaminate wash water, the industrial sanitizer peracetic acid (PAA) was added to the water, and the survival of MNV-1 was determined. In contrast to onions, spinach undergoes a heat treatment before freezing. Therefore, the resistance of MNV-1 to blanching of spinach was examined. MNV-1 genomic copies were detected with a real-time reverse transcription PCR assay in PAA-treated water and blanched spinach, and PFUs (representing infectious MNV-1 units) were determined with a plaque assay. A < or = 1-log reduction in MNV-1 PFUs was achieved by washing onion bulbs and spinach leaves. More than 3 log PFU of MNV-1 was transmitted to onion bulbs and spinach leaves when these vegetables were washed in water containing approximately 5 log PFU/ml. No decline of MNV-1 occurred in used industrial spinach wash water after 6 days at room temperature. A concentration of 20 ppm of PAA in demineralized water (pH 4.13) and in potable water (pH 7.70) resulted in reductions of 2.88 +/- 0.25 and 2.41 +/- 0.18 log PFU, respectively, after 5 min of exposure, but no decrease in number of genomic copies was observed. No reduction of MNV-1 PFUs was observed on frozen onions or spinach during storage for 6 months. Blanching spinach (80 degrees C for 1 min) resulted in at least 2.44-log reductions of infectious MNV-1, but many genomic copies were still present.
研究了通过清洗减少洋葱和菠菜上的鼠诺如病毒1型（MNV-1）以及清洗过程中的污染风险。为了对清洗用水进行消毒，向水中添加了工业消毒剂过氧乙酸（PAA），并测定了MNV-1的存活率。与洋葱不同，菠菜在冷冻前要经过热处理。因此，检测了MNV-1对菠菜热烫的抗性。通过实时逆转录PCR检测法在PAA处理过的水中和热烫后的菠菜中检测MNV-1基因组拷贝数，并用蚀斑试验测定蚀斑形成单位（代表感染性MNV-1单位）。清洗洋葱鳞茎和菠菜叶可使MNV-1蚀斑形成单位减少≤1个对数。当这些蔬菜在含有约5个对数蚀斑形成单位/毫升的水中清洗时，超过3个对数蚀斑形成单位的MNV-1会传播到洋葱鳞茎和菠菜叶上。室温下放置6天后，用过的工业菠菜清洗水中的MNV-1没有减少。去离子水（pH 4.13）和饮用水（pH 7.70）中PAA浓度为20 ppm时，暴露5分钟后分别使蚀斑形成单位减少2.88±0.25和2.41±0.18个对数，但未观察到基因组拷贝数减少。在冷冻的洋葱或菠菜储存6个月期间，未观察到MNV-1蚀斑形成单位减少。菠菜热烫（80℃，1分钟）可使感染性MNV-1至少减少2.44个对数，但仍存在许多基因组拷贝。
