Non-Thermal Sanitation by Atmospheric Pressure Plasma (SAPP)

NON-TECHNICAL SUMMARY: The Center for Disease Control (CDC) estimates that foodborne diseases cause 76 million illnesses and 5,000 deaths in the United States each year. Among outbreaks for which the cause was determined, bacterial pathogens caused the largest percentage of outbreaks (55%) and the largest percentage of cases (55%). Currently treatment of produce is done with chlorinated water to reduce populations of pathogenic and other microorganisms on fresh produce, but it cannot eliminate them. Irradiation of certain fresh fruits and vegetables is also an option, though one many consumers are not willing to accept. It is also difficult to transition into a hand-held, commercial restaurant device. A better method for sanitation in commercial food preparation is therefore needed to improve food safety for the general public. This proposed Sanitation by Atmospheric Pressure Plasma (SAPP) technology utilizes non-thermal, atmospheric pressure (AP) plasma, which is a high-energy electrical discharge occurred at ambient temperature and pressure. Non-thermal AP plasma has recently attracted much attention as an effective disinfection and decontamination technology, due to the high removal efficiency, energy yields, and low cost. Plasma processes are well known to be highly effective in promoting oxidation, enhancing molecular dissociation, producing highly reactive species, and generating other types of high energies to enhance chemical reactions. The special properties of non-thermal plasmas, especially those produced at ambient pressure without the need for vacuum, provide a great way to generate extremely reactive species and initiate a variety of chemical reactions at ambient temperature and pressure. The proposed SAPP technology supports sanitation of food preparation surfaces and equipment, food storage containers, and surface sanitation of fresh fruit and vegetables. It would provide a scalable solution for both processing and commercial use, which is a sizeable target market. This technology is efficient in terms of mass, power, volume, waste generated, and resource (e.g., water) use. In addition to a wide range of surface sanitation uses, components of this technology may be multipurpose. For example, the specially designed power supply could be used for high voltage pulsed electric field (PEF) food treatment, an emerging non-thermal technology that can sterilize packaged homogenous liquid foods, providing a tool for both surface sanitation, and packaged food sterilization. This technology may also have applications in air and water purification.

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APPROACH: Atmospheric-pressure plasma is well known to be highly effective in promoting oxidation, enhancing molecular dissociation, and producing free radicals and other types of high energies. It has recently attracted much attention in food industry due to its potential of being a non-thermal and highly effective sanitation method. This proposed non-thermal plasma sanitation technology supports sanitation of food preparation surfaces and equipment, food storage containers, and surface sanitation of fresh fruit and vegetables. It is efficient in terms of mass, power, volume, waste, and resource use. The specially designed power supply could also be used for high voltage pulsed electric field (PEF) food treatment, an emerging non-thermal technology that can sterilize packaged homogenous liquid foods, providing a tool for both surface sanitation, and packaged food sterilization. During this Phase I effort, a non-thermal plasma prototype will be designed, built, and optimized. Its sanitizing performance will be evaluated on tomato, lettuce, polypropylene, and Teflon substrates, all of which will be inoculated with E. coli O157:H7.