Graduate School of Life Sciences and Biotechnology, Korea University, Sungbuk-ku, Seoul, Republic of Korea.
Appl Environ Microbiol. 2011 Sep;77(18):6680-6. doi: 10.1128/AEM.05715-11. Epub 2011 Jul 29.
We developed and validated a treatment to inactivate Escherichia coli O157:H7 on radish seeds without decreasing seed viability. Treatments with aqueous ClO(2) followed by drying and dry-heat treatments were evaluated for efficacy to inactivate the pathogen. Conditions to dry radish seeds after treatment with water (control) or ClO(2) were established. When treated seeds with high water activity (a(w)) (>0.99) were stored at 45°C and 23% relative humidity (RH), the a(w) decreased to <0.30 within 24 h. Drying high-a(w) seeds before exposing them to dry-heat treatment (≥60°C) was essential to preserve seed viability. The germination rate of radish seeds which had been immersed in water for 5 min, dried at 45°C and 23% RH for 24 h, and heated at 70°C for 48 h or at 80°C for 24 h was not significantly decreased (P ≤ 0.05) compared to that of untreated radish seeds. Sequential treatments with ClO(2) (500 μg/ml, 5 min), drying (45°C, 23% RH, 24 h), and dry heating (70°C, 23% RH, 48 h) eliminated E. coli O157:H7 (5.9 log CFU/g) on radish seeds and, consequently, sprouts produced from them without decreasing the germination rate. These sequential treatments are recommended for application to radish seeds intended for sprout production.
我们开发并验证了一种在不降低萝卜种子活力的情况下使大肠杆菌 O157:H7 失活的处理方法。评估了用次氯酸 (ClO(2)) 水溶液处理后干燥和干热处理对病原体灭活的效果。建立了处理后用自来水（对照）或 ClO(2)干燥萝卜种子的条件。当高水活度（a(w)） (>0.99) 的处理种子在 45°C 和 23%相对湿度 (RH) 下储存时，a(w) 在 24 小时内降至 <0.30。在将高水活度的种子暴露于干热处理（≥60°C）之前对其进行干燥是保持种子活力的关键。将萝卜种子浸泡在水中 5 分钟，在 45°C 和 23% RH 下干燥 24 小时，然后在 70°C 下加热 48 小时或在 80°C 下加热 24 小时，其发芽率与未处理的萝卜种子相比没有显著降低（P ≤ 0.05）。用 ClO(2)（500 μg/ml，5 分钟）、干燥（45°C，23% RH，24 小时）和干热（70°C，23% RH，48 小时）的连续处理消除了萝卜种子上的大肠杆菌 O157:H7（5.9 log CFU/g），从而使从这些种子中长出的豆芽不会降低发芽率。这些连续处理方法建议用于打算生产豆芽的萝卜种子。
