Germicidal effect of pulsed bright light on microorganisms
Release time:
2023/03/20
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Pulsed light is a new technology that is expected to replace the traditional physical and chemical sterilization means, it is the use of instantaneous, high-intensity pulsed light energy, effectively kill bacteria, mold, spores, viruses, protoplasm, dormant spores and other types of microorganisms exposed to the surface of the food and packaging materials or water, as well as the endogenous enzymes in the food. Pulse light on all types of microorganisms sterilization effect is very obvious, and it is a non-mercury, low heat, no by-products of the new sterilization technology.
Pulse strong light is a new technology that is expected to replace traditional physical and chemical sterilization methods. It utilizes instantaneous, high-intensity pulse light energy to effectively kill various microorganisms such as bacteria, molds, spores, viruses, protoplasts, dormant spores, and endogenous enzymes in food that are exposed to the surface of food and packaging materials or water. Pulse strong light has a very obvious bactericidal effect on various microorganisms, and it is a new type of bactericidal technology that is mercury free, low heat, and no by-products.
1、 Pulse strong light sterilization mechanism
1. Photochemical action
Due to the presence of genetic information nucleic acid in bacterial cells, when the nucleic acid is irradiated by pulsed strong light, it absorbs a large amount of ultraviolet light, resulting in the formation of some isomers of m-diazobenzene and m-diazobenzene in the body. This substance can cause disorders in the metabolic function of bacteria themselves, and can lead to genetic problems in bacteria until death. The 200-280nm portion in pulsed strong light is easily absorbed, and the photochemical effect is mainly UVC.
2. Photothermal effect
Although the photochemical effect mainly comes from UVC, the UVA and UVB parts of pulsed strong light also play a certain bactericidal role. When the radiation dose reaches a certain level, UVA and UVB can rapidly increase the surface temperature of cells to 130 ° C, thereby damaging the cell wall of bacteria, causing evaporation of cell fluid, completely damaging the cell structure, and leading to death
2、 Experimental study on sterilization of Escherichia coli by pulsed strong light
1. Experimental equipment and parameters
A self-made pulse strong light sterilization device is used, which adopts a capacitive pulse generation circuit and is manually controlled. A straight tube pulse strong light lamp is used as the pulse light source, and a semi cylindrical reflective surface is used to concentrate light from the pulse light source. After testing, the wavelength range of the pulsed strong light emitted by the device is 200-1100nm, and the pulse width of the pulsed strong light is 20 μ s. The input energy is 644J. The light intensity, flash frequency, flash interval, and distance from the illuminated object to the light source of the device can be adjusted and controlled.
2. Experimental methods
2.1 Preparation of bacterial solution
Activate the Escherichia coli in the inclined test tube and inoculate it in sterile water on a sterile ultra clean workbench, with an inoculation amount controlled at 106-107 pieces/ml.
2.2 Processing methods
Each 75 mm diameter plate is filled with a certain volume of bacterial solution to be treated, placed in the center of the sterilization treatment room, 2 cm away from the light source, and subjected to pulse strong light flash treatment according to the set process parameters. The experiment is repeated 3 times each time.
2.3 Test parameter settings
Light intensity: 0 2, 0 25, 0 3, 0 375, 0.5, 0 625, 0 75 J/cm2; Number of flashes: 1, 2, 4, 8, 16; Bacterial liquid thickness: 3.4, 6 8, 10 2, 13 6, 17 cm; Bacterial liquid transmittance: 1, 2, 4, 8, 16, 32; Bacterial concentration (dilution ratio): 10, 100, 1000 times.
2.4 Lethal test for Escherichia coli
Dilute the processed bacterial solution at a ratio of 1:10
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The technical team of Zhongwu Optoelectronics Sterilization, a national level technology enterprise incubator and a incubating enterprise of Zhongwu Science and Technology Park in the national level innovation space, has developed and finalized a pulse strong light sterilization system with independent intellectual property rights through the incubation support of Zhongwu Science and Technology Park. It has become the world's third and the first pulse strong light sterilization system provider in China that integrates independent research and development, production, and sales.
Contact: Manager Zhou
Address: No. 165, West Section of Jingu Middle Road, Yinzhou District, Ningbo City