{
    "title": "Cold Plasma Food Preservation",
    "inventor_name": "Kevin Keener",
    "publication_year": 2009,
    "device_name": "Dielectric Barrier Discharge (DBD) Food Package Sterilizer",
    "goal": "Eliminate harmful bacteria in packaged foods without heating or contaminating the package.",
    "problem_addressed": "Food-borne illnesses caused by bacteria such as E. coli and Salmonella in packaged produce and other foods.",
    "concept_summary": "A high-voltage dielectric barrier discharge (DBD) creates a room-temperature plasma inside a sealed food package. The plasma ionizes the gases, producing ozone and other reactive oxygen species that kill bacteria. The system uses low-power electricity (30-40 W) and works with glass, plastic, and paper packaging.",
    "detailed_description": "Two low-watt, high-voltage coils are placed on the outside of a sealed package. When powered, a dielectric barrier discharge generates an atmospheric non-equilibrium plasma (ANEP) in the package interior. The plasma ionizes oxygen (and other gases) to form ozone (O_3), singlet oxygen, superoxide, peroxide, and hydroxyl radicals. These reactive species attack and destroy bacterial cell walls, achieving sterility within 30 seconds to five minutes. The process operates at near-ambient temperature, so the food is not cooked. The device can be powered by a small transformer and consumes less power than an incandescent bulb. It works with a range of packaging materials (LDPE, HDPE, PP, PET, cardboard, glass, etc.) and can be applied to pharmaceuticals as well.",
    "category": "Electromagnetism & Magnetism",
    "principles": [
        "Dielectric Barrier Discharge (DBD)",
        "Atmospheric non-equilibrium plasma (ANEP)",
        "In-situ ozone generation"
    ],
    "scientific_domains": [
        "Plasma Physics",
        "Food Science",
        "Microbiology"
    ],
    "mechanisms_of_action": [
        "Ionization of gases to produce reactive oxygen species",
        "Oxidative damage to bacterial cells by ozone and radicals"
    ],
    "materials": [
        "Air",
        "O_2",
        "N_2",
        "CO_2",
        "He",
        "Ar",
        "Dielectric layer (quartz, polymer)",
        "Copper coils"
    ],
    "energy_sources": [
        "Electrical power (30-40 W)"
    ],
    "inputs": [
        "Sealed food package containing product",
        "Ambient air or selected working gas"
    ],
    "outputs": [
        "Bacteria-free packaged food",
        "Ozone-rich atmosphere inside package (temporary)"
    ],
    "claimed_performance": "Effective kill of E. coli and Salmonella in 30 seconds to five minutes using 30-40 W of electricity; no temperature rise sufficient to cook the food.",
    "experimental_evidence": "Testing performed on spinach, tomatoes, glass containers, flexible plastic bags, rigid plastics, and pill bottles; figures in the patent show ozone concentrations and spore-reduction data for two DBD systems (13.5 kV RMS and 80 kV RMS).",
    "replication_status": "Patented (USPA 2014044595) and described in a peer-reviewed journal article; no commercial scaling reported.",
    "keywords": [
        "cold plasma",
        "dielectric barrier discharge",
        "ozone sterilization",
        "food safety",
        "non-thermal decontamination"
    ],
    "related_technologies": [
        "Ozone gas sterilization",
        "Atmospheric plasma treatment",
        "Non-thermal food preservation"
    ],
    "controversy_level": "low",
    "confidence_score": 0.9,
    "practicability_score": 0.8,
    "fringe_score": 0.2,
    "evidence_strength": 0.6,
    "risk_score": 0.1,
    "trl_estimate": 6,
    "source_urls": [
        "http://phys.org/news155230070.html",
        "https://patents.google.com/patent/US2014044595"
    ],
    "organizations": [
        "Purdue University"
    ],
    "applications": [
        "Food preservation",
        "Pharmaceutical sterilization",
        "Medical device packaging"
    ],
    "limitations": [
        "Requires sealed package",
        "Effectiveness depends on package material permeability",
        "Treatment time up to several minutes for dense loads"
    ],
    "open_questions": [
        "Impact of plasma treatment on nutritional quality and sensory attributes",
        "Scalability for high-throughput industrial packaging lines",
        "Long-term stability of ozone-treated foods"
    ],
    "red_flags": [],
    "evidence_quotes": [
        "A Purdue University researcher has found a way to eliminate bacteria in packaged foods such as spinach and tomatoes, a process that could eliminate worries concerning some food-borne illnesses.",
        "By placing two high-voltage, low-watt coils on the outside of a sealed food package, a plasma field is formed. In the plasma field, which is a charged cloud of gas, oxygen has been ionized and turned into ozone.",
        "The process uses only 30-40 watts of electricity, less than most incandescent light bulbs. The outside of the container only increases a few degrees in temperature, so its contents are not cooked or otherwise altered.",
        "Testing has worked with glass containers, flexible plastic-like food-storage bags and rigid plastics, such as strawberry cartons and pill bottles.",
        "Data for spore reductions resulting from treatment by the PK-1 DBD Ionization System (13.5 kV RMS) and PK-2 DBD Ionization System (80 kV RMS) are shown in Figures 5 and 6."
    ]
}