Food Engineering Progress (산업식품공학)

Korean Society for Industrial Food Engineering (한국산업식품공학회)
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Operational Characteristics and Microbial Inactivation Performance of Corona Discharge Plasma Jet System

코로나방전플라즈마제트장치의 조업특성과 살균력

  • Mok, Chulkyoon (Department of Food Science and Biotechnology, College of Engineering, Gachon University) ;
  • Lee, Taehoon (Department of Food Science and Biotechnology, College of Engineering, Gachon University)
  • 목철균 (가천대학교 식품생물공학과) ;
  • 이태훈 (가천대학교 식품생물공학과)
  • Published : 2013.08.31
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Abstract

A corona discharge plasma jet (CDPJ) treatment system was fabricated and its operation characteristics were determined. Also the microbial inactivation efficacy of CDPJ was evaluated in order to explore its potentialities as a nonthermal sterilization technology. The system consisted of power supply, transformer, electrode assembly, air blower, and sample treatment plate. Plasma was generated by corona discharge between tungsten lid electrodes with air stream blowing at high speed resulting in downward plasma ejection as a jet. Higher currents and, consequently, greater power were required for the plasma generation as the frequencies increased. Plasmas were generated at a current greater than 1.0 A and frequencies over 32.5 kHz. Stable plasma jets were acquired when the current and the frequency exceeded 1.5 A and 40.0 kHz. Plasma jet length was extended with the current strength. The maximum temperature increased after a 2 min treatment was less than $25^{\circ}C$ regardless of the current strength, indicating that the technology belonged to the non-thermal processing category. The CDPJ inactivation effect against Escherichia coli increased with the current strength. More than 4.5 log reduction was achieved by 1 min treatment at 1.5 A. The inactivation pattern fitted to a 2-stage 1st order reaction model.

코로나방전플라즈마제트(CDPJ) 생성장치를 제작하여 조업특성을 조사하고 비가열살균기술로서의 활용가능성을 탐색하고자 E. coli를 대상으로 살균성능을 조사하였다. CDPJ장치는 전력공급장치, 변압기, 전극, 송풍기, 시료처리부 등 다섯 부분으로 구성하였다. 전압 10.0-20.0 kV의 직류전기를 10.0-45.0 kHz 구형파 펄스형태로 텅스텐리드 전극에 투입함으로써 코로나방전 플라즈마를 생성하고 동시에 전극사이로 강한 공기를 주입함으로써 하부방향으로 토출하는 플라즈마제트를 생성하였다. CDPJ 처리는 플라즈마 토출구 하부에 처리대상 물체를 위치하고 일정시간 처리하는 방식으로 시행하였다. 주파수를 높일수록 다량의 전류가 유입되었고, 비례하여 전력소비량도 증가하였다. 플라즈마 생성을 위한 임계전류는 1.0 A, 임계주파수는 32.5 kHz이었으며, 1.5 A 이상 40.0 kHz 이상에서 안정적인 플라즈마제트가 생성되었다. 플라즈마제트의 길이는 전류에 따라 증가하였고, 2분 이하 처리 시 대상물체의 표면온도 상승은 $25^{\circ}C$를 하회하였다. E. coli 살균력은 전류세기에 비례하여 증가하였고, 전류 1.5 A에서 1분간 CDPJ처리에 의해 4.5 log 이상의 살균효과를 보였으며, 살균패턴은 2단계 1차 반응으로 확인되었다.

Keywords

References

  1. Becker N, Schmidt M, Viggiano AA, Dresslar R, Williams S. 2005. Air plasma chemistry. In: Non-equilibrium Air Plasmas at Atmospheric Pressure. Becker KM, Kogelschartz U, Schoenback KH, Barker RJ (eds.). IOP Publishing Ltd., London, England, pp. 124-182.
  2. Deng S, Ruan R, Mok C, Huang G, Lin X, Chen P. 2007. Inactivation of Escherichia coli on almonds using nonthermal plasma. J. Food Sci. 72: M62-M65. https://doi.org/10.1111/j.1750-3841.2007.00275.x
  3. KFDA. 2005. Food Codes Vol. II. Korea Food and Drug Administration, Seoul, Korea, p. 97.
  4. Kuwahara T, Kuroki T, Yoshida K, Saeki N, Okubo M. 2012. Development of sterilization device using air nonthermal plasma jet induced by atmospheric pressure corona discharge. Thin Solid Films 523: 2-5. https://doi.org/10.1016/j.tsf.2012.05.064
  5. Lerouge S, Wertheimer MR, Yahia L. 2001. Plasma sterilization: a review of parameters, mechanisms, and limitations. Plasmas Polym. 6: 175-188. https://doi.org/10.1023/A:1013196629791
  6. Moisan M, Berbeau J, Crevier MC, Pelletier J, Philip N, Saoudi B. 2002. Plasma sterilization: methods and mechanisms. Pure Appl. Chem. 74: 349-358. https://doi.org/10.1351/pac200274030349
  7. Mok C, Song DM. 2010. Low-pressure plasma inactivation of Escherichia coli. Food Eng. Prog. 14: 202-207.
  8. Mok C, Lee T. 2011. Operational properties and microbial inactivation performance of dielectric barrier discharge plasma treatment system. Food Eng. Prog. 15: 398-403.
  9. Mok C, Lee T. 2012. Dielectric barrier discharge plasma inactivation of Escherichia coli. Food Eng. Prog. 16: 33-39.
  10. Montie TC, Kelly-Winternberg K, Roth JR. 2000. An overview of research using the one atmosphere uniform glow discharge plasma (OAUGDP) for sterilization of surfaces and materials. IEEE Trans. Plasma Sci. 28: 41-50. https://doi.org/10.1109/27.842860
  11. SAS Institute, Inc. 2004. SAS/STAT 9.1 User's Guide. SAS Institute, Cary, NC, USA.
  12. Xu L, Liu P, Zhan RJ, Wen XH, Ding LL, Nagatsu M. 2006. Experimental study and sterilizing application of atmospheric pressure plasmas. Thin Solid Films 506-507: 400-403. https://doi.org/10.1016/j.tsf.2005.08.100

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