HIGH VOLTAGE ATMOSPHERIC COLD PLASMA

Kevin M. Keener - Professor of Food Science

Purdue University, West Lafayette

N.N. Misra – IRC Embark Fellow

Dana Ziuzina – PhD Research Student,

School of Food Science Environmental Health, Dublin Institute of Technology, Dublin, Ireland

PJ Cullen – Senior Lecturer

School of Chemical Engineering, UNSW Australia

  High Voltage Atmospheric Cold Plasma demonstrates a new and innovative idea on the development of a high-voltage atmospheric cold plasma (HVACP) that can achieve bactericidal and sporicidal reductions in sealed packages of much larger size than is currently feasible.  Published HVACP studies using air have demonstrated pasteurization and sterilization of spores, fungus, and bacteria on agricultural, food, pharmaceutical, and medical products.  The HVACP technology is ten to one hundred times more effective than current ACP systems.  In addition, the sealed package HVACP technology affords manufacturers the advantage of a low energy, non-thermal, post-package treatment to improve product safety and extend shelf life. 

The fundamental discovery in the process was the demonstration that a high electric field can be conveyed through a dielectric material (e.g., wood, plastic, glass, etc.) without significant energy losses. The dielectric material limits current flow from the electrode into the gas, resulting in a very low energy process. To create a HVACP plasma inside a 1 gallon zippered plastic bag only required 100 W of energy delivered for 15 seconds.  The resulting ionization of the air inside the package produces reactive oxygen and excited nitrogen molecules, as well as ultraviolet light, which have proven antimicrobial effects.

The key advantage of in-package cold plasma treatment is that the bactericidal molecules are generated and contained in the package, allowing extended exposure to pathogenic microbes while reverting back to the original gas within a few hours of storage.  Unlike most conventional food technologies, the antimicrobial treatment inside a sealed package ensures the prevention of post-processing contamination.  HVACP treatment is a non-thermal process, resulting in a minimal rise in temperature even after extended processing times of minutes to hours.  This technology has a great and lasting impact on safe storage of agricultural, food, pharmaceutical, and medical, and other packaged products.  The in-package HVACP technology is a patented process, and the pre-commercial prototype is being tested on fruit and vegetables at the research partners’ manufacturing sites.