From Top Wiki
Cold plasma or: non-thermal plasma is a high-energetic, ionized gas with a temperature of 30-60 C. Ionization generates reactive molecules: plasmas produced from oxygen gas are sources of electrons, radicals, ozone etc. Noble gases are used to produce radical-free plasma.
Possible mechanisms of action against microorganisms include these radicals, electrons and ozone, UV and heat. The thermal effect is low, due to the mild temperature. The plasma effect depends on the product, treatment time, chosen gas and treatment temperature. Not much is known about which components are formed, which micro-organisms are sensitive, how the plasma activity can be influenced and the effect on food quality parameters.
Radicals cause oxidation of bacterial cell membranes, causing denaturation and cell leakage. Oxidation of amino acids and nucleic acids may also result in microbial death or injury. Cold plasma can inactivate both vegetative cells and spores of microorganisms. The radicals can affect food quality, by oxidizing food, inducing rancidity in fatty products and vitamin loss.
There are two possible equipment layouts:
- 2 parallel electrodes with a plasma between them. The product moves between the electrodes to receive treatment, and
- plasma pen or jet, in which a stream of plasma can be directed at the object to be treated.
As far as we know, no commercial systems are available for disinfection of foods with plasma. Research institutes have lab-scale equipment available for treatment of small quantities of product. More research is needed for scaling-up before industrial scale equipment can be produced.
Industrial equipment is available for changing surface properties of non-food materials (metals, plastics), odour removal in air / exhausts and drinking / waste water treatment. Pilot equipment is available for the sterilization of medical supplies.
Surface treatment and etching of non-food materials http://www.plasmatechsystems.com/ www.tri-star-technologies.com/ http://www.plasmatechnology.de/?gclid=CMqFmsrghLoCFfDMtAod3zQAMA http://www.plasma.de/en/index.html?gclid=CIP36obhhLoCFQ0Q3godzS0AnA
Odour removal in air / exhaust http://www.lenntech.nl/luchtzuivering/gaszuiveringstechnieken/ionisatie.htm http://www.appliedplasma.com/
Pros and cons
- Plasma can penetrate slight product cracks and crevices
- No shadow effect
- Inactivation of cells,spores, virusses and prions
- Non-thermal, so low heat impact
- Disinfection degree depends on material type and plasma type
- Oxidation of fat and loss of vitamins
- Little known about inactivation on real food
- No commercial equipment available for disinfection of food
Since no industrial equipment is available, we cannot estimate the investment- and running costs.