Method and apparatus for cold plasma food contact surface sanitation
A cold plasma device for killing or reducing a microbiological pathogen, or denaturing a protein in food, in a food processing system using a cold plasma device. The cold plasma device directs a cold plasma at food or a food surface over an effective area for an effective amount of time. The cold plasma device can be a DBD electrode device, or an army of DBD electrode devices. A grounding rod assembly is also described.
1. A method comprising:
contacting a target substrate with a multi-frequency harmonic-rich cold plasma over an effective area for an effective amount of time to kill or reduce a microbiological pathogen, or denaturing a protein, in a food processing system, wherein the cold plasma is generated by a scalable cold plasma device capable of providing cold plasmas having dimensions from 25 cm through to at least 8 linear feet.
2. The method of claim 1 , wherein the contacting the target substrate includes contacting a conveyer belt in the food processing system.
3. The method of claim 2 , wherein the contacting the conveyer belt occurs when the conveyer belt is on its return path following conveyance of food.
4. The method of claim 1 , wherein the contacting the target substrate includes using the multi-frequency harmonic-rich cold plasma produced by a dielectric barrier discharge (DBD) electrode device.
5. The method of claim 1 , wherein the contacting the target substrate includes using the multi-frequency harmonic-rich cold plasma produced by an array of DBD electrode devices.
6. The method of claim 1 , wherein the contacting the target substrate includes using the multi-frequency harmonic-rich cold plasma produced by an atmospheric pressure plasma jet device.
7. The method of claim 1 , wherein the contacting the target substrate includes using the multi-frequency harmonic-rich cold plasma produced by an array of atmospheric pressure plasma jet devices.
8. The method of claim 1 , wherein the contacting the target substrate with a multi-frequency harmonic-rich cold plasma includes using a DBD electrode device having an electrode length longer than 25 cm, or the effective area is in excess of 5 sq. cm.
9. The method of claim 1 , further comprising:
using a grounding assembly configured with the scalable cold plasma device to surround a food contact surface area.
10. The method of claim 1 , further comprising:
using a frame configured to support the scalable cold plasma device and to direct the cold plasma to food processing equipment.
11. The method of claim 1 , further comprising:
providing the scalable cold plasma device with an electrical voltage having two or more harmonic frequencies using a cold plasma power supply coupled to the scalable cold plasma device.
12. The method of claim 1 , wherein the contacting the target substrate includes contacting food.
13. The method of claim 1 , further comprising:
using a grounding assembly configured with the scalable cold plasma device to surround a food contact surface area, the grounding assembly having a shape associated with a particular application.
14. The method of claim 1 , wherein the contacting the target substrate with the multi-frequency harmonic-rich cold plasma over the effective area for the effective amount of time includes using the effective amount of time sufficient to achieve sanitation at a conveyor belt speed in a food handling operation.
15. The method of claim 1 , wherein the contacting the target substrate includes using the multi-frequency harmonic-rich cold plasma produced by a DBD electrode device, the DBD electrode device having an electrode of length at least 25 cm.
16. The method of claim 1 , wherein the contacting the target substrate with the multi-frequency harmonic-rich cold plasma includes using a multi-frequency harmonic-rich cold plasma having a length of at least 8 linear feet generated from a single cold plasma power source.
17. The method of claim 1 , further comprising:
using one or more grounding elements configured to tailor the multi-frequency harmonic-rich cold plasma to a predetermined shape, contour or region.
18. The method of claim 2 , wherein the contacting the conveyer belt includes contacting a variable speed conveyer belt.
19. The method of claim 2 , wherein the contacting the conveyer belt includes contacting a conveyer belt comprising a non-conductive surface.
20. The method of claim 4 , wherein the DBD electrode device comprises a metallic tube shrouded in a dielectric coating.
21. The method of claim 20 , wherein the dielectric coating comprises polytetrafluoroethylene (PTFE), delrin, polyethylene (PE), polypropylene (PP), quartz, or glass.
22. The method of claim 4 , wherein the DBD electrode device includes an electrode having a cross-sectional shape that comprises a circular shape, polygonal shape or a planar shape.
23. The method of claim 1 , further comprising:
contacting the target substrate with ultraviolet light from a fluorescent bulb.
24. The method of claim 1 , wherein the multi-frequency harmonic-rich cold plasma results from a power supply that provides electrical energy across a multitude of frequencies to the scalable cold plasma device.