Yong Hae In, Kim Hyun-Joo, Park Sanghoo, Choe Wonho, Oh Mi Wha, Jo Cheorun
1 Department of Agricultural Biotechnology, Center for Food and Bioconvergence, Research Institute of Agriculture and Life Science, Seoul National University , Seoul, Korea.
Foodborne Pathog Dis. 2014 Aug;11(8):652-7. doi: 10.1089/fpd.2013.1718. Epub 2014 May 20.
Atmospheric pressure plasma (APP) is an emerging nonthermal microbial inactivation technique. In this study, agar and raw chicken breast were inoculated with Escherichia coli and treated with an APP jet based on cold arc plasma. The aim of this study was to investigate the optimum conditions for the plasma treatment of an APP jet in order to maximize the efficiency of E. coli inactivation. The combination of N2+O2 (10 standard cubic centimeters per minute) and a longer treatment time (10 min) resulted in the highest inactivation of E. coli on agar plates with an optimum treatment distance of 20 mm. The samples in dry and wet conditions showed similar reductions in E. coli count when one side of the samples was treated at a given treatment time. Treating both sides-2.5 min on each side-resulted in a higher growth inhibition of E. coli than treatment of a single side only for 5 min. However, there was no significant difference between one-side treated samples (10 min) and both-sides treated samples (5+5 min). When the concentration of E. coli in the chicken breast sample was 10(4) colony-forming units (CFU)/g, the reduction rate of the E. coli was the highest, followed by 10(5), 10(6), and 10(7) CFU/g; however, no difference was found between 10(3) and 10(4) CFU/g. In conclusion, various treatment conditions may affect the inactivation efficiency of E. coli. In the present study, the optimum condition was determined as the treatment distance of 20 mm and longer treatment time (10 min) with the addition of oxygen to the nitrogen gas flow. Furthermore, the cell concentration of sample was an important parameter for the efficacy of the inactivation process.
大气压等离子体（APP）是一种新兴的非热微生物灭活技术。在本研究中，将大肠杆菌接种到琼脂和生鸡胸肉上，并用基于冷弧等离子体的APP射流进行处理。本研究的目的是研究APP射流等离子体处理的最佳条件，以最大限度地提高大肠杆菌的灭活效率。N2+O2（每分钟10标准立方厘米）与较长的处理时间（10分钟）相结合，在琼脂平板上实现了对大肠杆菌的最高灭活率，最佳处理距离为20毫米。在给定处理时间对样品一侧进行处理时，干燥和湿润条件下的样品大肠杆菌数量减少情况相似。对两侧进行处理（每侧2.5分钟）比仅对一侧处理5分钟对大肠杆菌的生长抑制作用更强。然而，单侧处理10分钟的样品与双侧处理（5+5分钟）的样品之间没有显著差异。当鸡胸肉样品中大肠杆菌浓度为10(4) 菌落形成单位（CFU）/克时，大肠杆菌的减少率最高，其次是10(5)、10(6)和10(7) CFU/克；然而，10(3)和10(4) CFU/克之间没有差异。总之，各种处理条件可能会影响大肠杆菌的灭活效率。在本研究中，最佳条件确定为处理距离20毫米、较长的处理时间（10分钟）以及在氮气气流中添加氧气。此外，样品的细胞浓度是灭活过程效果的一个重要参数。
