Method of controlling microorganisms by pulsed ultraviolet laser radiation
First Claim
1. A method of controlling undesired microorganisms on the surface of food, comprising the step of irradiating the surface of a food object containing undesired microorganisms with a plurality of monochromatic, ultraviolet light pulses wherein said microorganisms are reduced or eliminated by destructively altering nucleic acid based structures in said microorganisms with said irradiation without alteration of surface properties of said food object.
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Abstract
Microorganisms, including not only bacteria related to hygiene, food spoilage and human pathogenesis but also fungi which are commonly found in fresh fruits and vegetables, can be reduced or eliminated for surface microbial disinfection of foods and for other purposes by exposing an area containing such microorganisms to a monochromatic beam of pulsed ultraviolet laser radiation of wavelength about 240-280 nm, or in particular about 240-260 nm, with pulse duration in the range of picoseconds to microseconds at 1-1900 mJ/cm2 for most situations. Laser energy irradiance should be controlled in the case of some foods because of the limited tolerance to such exposure.
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Citations
20 Claims
- 1. A method of controlling undesired microorganisms on the surface of food, comprising the step of irradiating the surface of a food object containing undesired microorganisms with a plurality of monochromatic, ultraviolet light pulses wherein said microorganisms are reduced or eliminated by destructively altering nucleic acid based structures in said microorganisms with said irradiation without alteration of surface properties of said food object.
- 6. A method of controlling microorganisms on the surface of a food object, comprising the step of destructively altering nucleic acid based structures in said microorganisms by irradiating said microorganisms on the surface of a food object with a plurality of monochromatic, ultraviolet light pulses for less than approximately one second, said light pulses having a duration ranging from approximately 1 ns to 100 ns, and said light pulses having energy densities ranging from approximately 1 to 2 J/cm2, wherein said microorganisms are reduced or eliminated by said irradiation without affecting surface characteristics of said food object.
- 17. A method of controlling microbial contamination without altering the visual appearance of food surfaces, comprising the step of destructively altering nucleic acid based structures in contaminating microbes on a food surface by irradiating said food surface with a plurality of monochromatic, ultraviolet light pulses, wherein said microbes are reduced or eliminated by said irradiation without altering surface properties.
Specification