本文以自来水清洗为对照，研究了在30 ℃下用50 W功率超声波分别清洗鲜切芹菜10 min、15 min、20 min、25 min、30 min各样品中细菌和大肠杆菌的数量变化，以及亚硝酸盐和维生素C的变化情况，探索鲜切芹菜保鲜的最佳清洗方法和时间。实验表明超声波处理10 min的鲜切芹菜除菌率高，无机械损伤，对VC无明显破坏作用，感官品质优良，有利于芹菜的保鲜。

The vegetables are cleaned with the low-power ultrasonic at 30 ℃ for different time (10minites, 15 minutes, 20 minutes, 25minites and 30minites). The total counts of bacteria and E.coil were determined and the physical and chemical indicators were also measured. Ultrasonic Cleaning for 10minute showed high bacterial-eliminating rate and little mechanical damage to Vc, which was suitable for fresh-keeping of the celery.