Department of Food Science and Technology, University of Tennessee, Knoxville, Tennessee 37996, USA.
Foodborne Pathog Dis. 2010 Sep;7(9):1055-61. doi: 10.1089/fpd.2009.0515.
Foodborne viruses, especially human noroviruses, are recognized as leading causes of nonbacterial gastroenteritis worldwide. Development of effective inactivation methods is of great importance to control their spread. In this study, the effect of high-intensity ultrasound (HIUS) on the infectivity of three foodborne virus surrogates was investigated. The three surrogates, murine norovirus (MNV-1), feline calicivirus (FCV-F9), and MS2 bacteriophage, were diluted in phosphate-buffered saline (PBS) or orange juice to a titer of approximately 6 log(10) PFU/mL or approximately 4 log(10) PFU/mL. The ultrasound treatment was performed in duplicate by immersing the HIUS probe in virus-containing solution that was cooled in ice-water and sonicated at 20 kHz for 2, 5, 10, 15, 20, and 30 min with 30 sec on and 30 sec off. The infectivity of the recovered viruses after each ultrasound treatment was evaluated in duplicate using standardized plaque assays and compared to untreated controls. The results show that HIUS effectiveness depended on the virus type, the initial titer of the viruses, and the virus suspension solution. At titers of approximately 4 log(10) PFU/mL in PBS, feline calicivirus (FCV)-F9, MS2, and murine norovirus (MNV)-1 required 5-, 10-, and 30-min treatment, respectively, for complete inactivation. At initial titers of approximately 4 log(10) PFU/mL in orange juice, FCV-F9 required a 15-min treatment for complete inactivation and only a 1.55 log(10) PFU/mL reduction was achieved for MNV-1 in orange juice after 30-min treatment. Thus, inactivation by HIUS in orange juice was much lower than in PBS. Experiments using titers of approximately 6 log(10) PFU/mL showed decreased effects compared to those using titers of approximately 4 log(10) PFU/mL. These results indicate that HIUS alone is not sufficient to inactivate virus in food. Hurdle technologies that combine HIUS with antimicrobials, heat, or pressure should be explored for viral inactivation.
食源病毒，尤其是人类诺如病毒，被认为是全球非细菌性肠胃炎的主要致病原因。开发有效的灭活方法对于控制其传播非常重要。本研究考察了高强度超声（HIUS）对三种食源病毒替代物感染性的影响。三种替代物为鼠诺如病毒（MNV-1）、猫杯状病毒（FCV-F9）和 MS2 噬菌体，用磷酸盐缓冲盐水（PBS）或橙汁稀释至约 6 log(10)PFU/mL 或约 4 log(10)PFU/mL 滴度。将 HIUS 探头浸入含有病毒的溶液中，在冰水中冷却，然后以 20 kHz 频率进行超声处理，每次 2、5、10、15、20 和 30 分钟，开 30 秒，关 30 秒，重复两次。用标准化噬斑试验评估每种超声处理后回收病毒的感染性，并与未处理的对照进行比较。结果表明，HIUS 的有效性取决于病毒类型、病毒初始滴度和病毒悬浮液。在 PBS 中约 4 log(10)PFU/mL 的滴度下，猫杯状病毒（FCV）-F9、MS2 和鼠诺如病毒（MNV）-1 分别需要 5、10 和 30 分钟的处理才能完全灭活。在橙汁中初始滴度约为 4 log(10)PFU/mL 时，FCV-F9 需要 15 分钟的处理才能完全灭活，而在 30 分钟处理后，橙汁中的 MNV-1 仅减少了 1.55 log(10)PFU/mL。因此，HIUS 在橙汁中的灭活效果远低于 PBS。使用约 6 log(10)PFU/mL 滴度的实验显示，与使用约 4 log(10)PFU/mL 滴度的实验相比，效果降低。这些结果表明，单独使用 HIUS 不足以使食品中的病毒失活。应探索将 HIUS 与抗菌剂、热或压力相结合的障碍技术来实现病毒灭活。
