Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
J Food Prot. 2012 Mar;75(3):563-6. doi: 10.4315/0362-028X.JFP-11-218.
This study was undertaken to examine the effect of ultrasound in combination with chlorine on the reduction of Escherichia coli O157:H7 populations on lettuce coring knives. Two new coring devices designed to mitigate pathogen attachment were fabricated and evaluated. The coring rings of the knives were dip inoculated with soil slurry containing 10⁶ E. coli cells and treated with chlorinated water with and without ultrasonication for 30, 60, and 120 s. The rough welding joints on currently used in-field lettuce coring knives provided a site conducive to bacterial attachment and resistant to cell removal during sanitation treatment. The two modified coring knives harbored significantly fewer E. coli cells than did the currently used commercial model, and the efficacy of the disinfection treatment was high (P < 0.05). Ultrasound treatment reduced the E. coli O157:H7 counts to below the detection limit of 1.10 log CFU/cm² at both the coring ring blade and welding joint within 30 s in 1 ppm of chlorinated water. The redesigned coring knives and an ultrasound plus chlorine combination treatment may provide practical options for minimizing the microbial safety hazards of lettuce processed by core-in-field operations.
本研究旨在探讨超声联合氯对减少生菜芯刀上大肠杆菌 O157:H7 种群的影响。设计并评估了两种新的装置来减轻病原体附着。将含有 10⁶ 个大肠杆菌细胞的土壤浆体滴涂到刀的芯孔环上，并用含有和不含有超声的氯水处理 30、60 和 120 秒。目前在田间使用的生菜芯刀上的粗糙焊接接头为细菌附着提供了有利条件，并在卫生处理过程中抵抗细胞去除。与目前使用的商用模型相比，两种改良的芯孔刀上的大肠杆菌细胞数量明显减少，消毒处理效果显著（P<0.05）。在 1 ppm 氯水中，超声处理在 30 秒内将大肠杆菌 O157:H7 的数量减少到 1.10 log CFU/cm² 以下，无论是在芯孔环刀片还是焊接接头处均低于检测限。重新设计的芯孔刀和超声加氯联合处理可能为最大限度地减少田间芯部操作处理的生菜的微生物安全危害提供实用选择。
