Inactivation kinetics of Escherichia coli by pulsed electron beam
Inactivation kinetics of Escherichia coli by pulsed electron beam
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DOI：
10.1111/j.1750-3841.2007.00451.x
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发表时间：
2007-09-01
影响因子：
3.9
通讯作者：
Jaczynski, J.
中科院分区：
文献类型：
--
作者：
Chalise, P. R.;Hotta, E.;Jaczynski, J.
设计并制造了一种新型的利用次级发射电子枪（SEEG）的低能量（keV）高功率脉冲电子束（e-beam）。将浓度为10（6）CFU/mL的大肠杆菌JM 109涂布在Luria-Bertani（LB）培养基上并进行SEEG电子束。电子束作为1或5个脉冲施用。单脉冲的持续时间恒定在5 μ s，电子束电流密度恒定在25 mA/cm（2），电子束能量在60和82.5 keV之间变化。在SEEG电子束治疗后，照射E。大肠杆菌样品通过标准10倍稀释计数并涂布平板。以对数标度绘制存活曲线作为电子束剂量的函数。D-10值计算为存活曲线斜率的负倒数。E. 1脉冲和5脉冲SEEG电子束灭活大肠杆菌的平均剂量分别为0.0026和0.0217戈伊。这些D-10值大大低于E的已发表D-10值。大肠杆菌灭活与传统的高能连续电子束可能是由于较短的曝光时间（t），较大的电流密度（J），和脉冲模式的SEEG电子束。SEEG电子束显示出以非热方式进行微生物灭活的有希望的结果;然而，由于SEEG电子束的低能量，目前的应用仅限于表面去污。SEEG电子束可能是即食产品（包括新鲜和多叶蔬菜）上食源性病原体表面灭活的有效加工步骤。
A novel and compact low-energy (keV) high-power pulsed electron beam (e-beam) that utilizes a secondary emission electron gun (SEEG) was designed and constructed. Escherichia coli JM 109 at a concentration of 10(6) CFU/mL was spread-plated on Luria-Bertani (LB) medium and subjected to the SEEG e-beam. The e-beam was administered as 1 or 5 pulses. The duration of a single pulse was constant at 5 mu s, e-beam current density was constant at 25 mA/cm(2), and e-beam energy varied between 60 and 82.5 keV. Following treatment with the SEEG e-beam, survivors of the irradiated E. coli samples were enumerated by a standard 10-fold dilution and spread-plated. The survivor curves were plotted on logarithmic scale as a function of e-beam dose. The D-10-values were calculated as a negative reciprocal of the slope of the survivor curves. The D-10-values for E. coli inactivated with 1- and 5-pulse SEEG e-beam were 0.0026 and 0.0217 Gy, respectively. These D-10-values were considerably lower than published D-10-values for E. coli inactivated with conventional high-energy continuous e-beam likely due to shorter exposure time (t), greater current density (J), and a pulse mode of the SEEG e-beam. The SEEG e-beam showed promising results for microbial inactivation in a nonthermal manner; however, due to low energy of the SEEG e-beam, current applications are limited to surface decontamination. The SEEG e-beam may be an efficient processing step for surface inactivation of food-borne pathogens on ready-to-eat products, including fresh and leafy vegetables.