Graduate School of Life Sciences and Biotechnology, Korea University, Seoul, Republic of Korea.
Food Microbiol. 2011 Feb;28(1):114-8. doi: 10.1016/j.fm.2010.09.002. Epub 2010 Sep 16.
We determined the combined effectiveness of ClO(2) (200 and 500 μg/ml, 5 min), air drying [25 °C, 40% relative humidity (RH), 2 h], and mild dry heat (55 °C, 23% RH, up to 48 h) treatments in killing total aerobic bacteria (TAB), Escherichia coli O157:H7, and molds and yeasts (MY) on radish seeds. A 5.1-log reduction in the number of TAB was achieved on radish seeds treated with 200 or 500 μg/ml ClO(2) followed by air drying for 2 h and dry heat treatment for 48 h or 24 h, respectively. When radish seeds were treated with 200 and 500 μg/ml ClO(2), air dried, and heat treated for 12 h and 6 h, respectively, the initial population of E. coli O157:H7 (5.6 log CFU/g) on seeds was reduced to an undetectable level (<0.8 log CFU/g). However, the pathogen was detected in 5-day-old sprouts. The reduction of MY (1.2-1.0 log CFU/g) on radish seeds under similar experimental conditions was not changed significantly during subsequent heat treatment up to 48 h. Results show that treating radish seeds with 500 μg/ml ClO(2), followed by air dried at 25 °C for 2 h and heat treatment at 55 °C for 36 h achieved a >5-log CFU/g reduction of TAB and E. coli O157:H7. These observations will be useful when developing effective strategies and practices to enhance the microbiological safety of radish sprouts.
我们确定了 ClO₂（200 和 500μg/ml，5 分钟）、空气干燥[25°C，40%相对湿度（RH），2 小时]和温和干热（55°C，23%RH，最长 48 小时）处理联合作用对萝卜种子上总需氧菌（TAB）、大肠杆菌 O157:H7 和霉菌和酵母菌（MY）的杀灭效果。用 200 或 500μg/ml ClO₂处理萝卜种子，然后空气干燥 2 小时，再进行干热处理 48 或 24 小时，可使 TAB 的数量减少 5.1 对数。用 200 和 500μg/ml ClO₂处理萝卜种子，空气干燥，分别热处理 12 小时和 6 小时后，种子上大肠杆菌 O157:H7 的初始菌数（5.6logCFU/g）减少到无法检测的水平（<0.8logCFU/g）。然而，在 5 天龄的豆芽中仍能检测到病原体。在类似的实验条件下，霉菌（1.2-1.0logCFU/g）在萝卜种子上的减少在随后的 48 小时热处理中没有明显变化。结果表明，用 500μg/ml ClO₂处理萝卜种子，然后在 25°C 下空气干燥 2 小时，再在 55°C 下热处理 36 小时，可使 TAB 和大肠杆菌 O157:H7 的减少量达到>5-logCFU/g。这些观察结果将有助于制定有效的策略和实践，以提高萝卜芽的微生物安全性。
