JP2023014717A - Inactivating method and inactivating device - Google Patents

Abstract

An inactivation method and an inactivation device are provided for easily inactivating microorganisms and viruses harmful to humans and animals adhering to the surface of fish and shellfish without adversely affecting the fish and shellfish. The inactivation method includes the step of irradiating from a light source ultraviolet rays with a wavelength of 200 nm or more and 240 nm or less that are absorbed by the protein components on the surface of the fish and shellfish; to inactivate microorganisms and/or viruses present on the surface of the seafood. [Selection drawing] Fig. 2

Description

TECHNICAL FIELD The present invention relates to an inactivation method and an inactivation device for inactivating harmful microorganisms and viruses.

Conventionally, there is a high demand for live fish by consumers. In order to meet such demand, live seafood is transported to supermarkets and other fresh food counters and restaurants. Such live fish are handled by people with bare hands when they are sold at the destination or when they are cooked and processed.
In some aquariums, facilities are provided that allow viewers to come into direct contact with the fish on display. Such facilities are popular with customers who appreciate fish, and many unspecified people have many opportunities to touch live fish with their bare hands.

However, if the surface of fish (seafood) that people may come into contact with with their bare hands has microorganisms or viruses that are harmful to humans, contact with the fish and shellfish may cause the above-mentioned microorganisms or Viruses infect humans. In this case, the routes of infection of harmful microorganisms and viruses include fish and shellfish→human, human→fish and shellfish→human, and animal→fish and shellfish→human.
In addition, the above-mentioned infection from seafood to humans is not limited to contact with live fish. This is also true for non-live fish, such as fish that are slaughtered and transported to market.

For example, Patent Document 1 discloses a technique of immersing fish and shellfish in ozonated water, applying a magnetic field to remove fungi adhering to the surface of the fish and shellfish, and sterilizing the removed fungi with ozonated water. ing.

JP-A-4-152873

In the technique described in Patent Document 1, it is possible to sterilize fungi removed from the surface of seafood with ozone water. However, ozone can have an adverse effect on seafood such as damaging it or impairing its flavor. Moreover, ozone is harmful to the human body. Therefore, it is necessary to safely manage the ozone when the ozonized water is produced, and the ozone concentration control of the ozonated water becomes complicated.
Therefore, the present invention provides an inactivation method and an inactivation device for easily inactivating microorganisms and viruses that are harmful to humans and animals adhering to the surface of fish and shellfish without adversely affecting the fish and shellfish. The challenge is to provide

In order to solve the above problems, one aspect of the inactivation method according to the present invention is to radiate ultraviolet rays with a wavelength of 200 nm or more and 240 nm or less that are absorbed by protein components on the surface of seafood from a light source; exposing the emitted ultraviolet rays to the protein components on the surface of the seafood to inactivate microorganisms and/or viruses present on the surface of the seafood.

In this way, by irradiating the surface of the fish and shellfish with ultraviolet rays having a wavelength of 200 nm or more and 240 nm or less, it is possible to inactivate microorganisms and viruses adhering to the surface of the fish and shellfish. Here, the ultraviolet rays with a wavelength of 200 nm or more and 240 nm or less are ultraviolet rays that do not generate ozone, are absorbed by the protein components on the surface of the fish and shellfish, and do not penetrate inside the fish and shellfish. Therefore, it is possible to inactivate microorganisms and viruses on the surface of fish and shellfish without generating ozone and without damaging the fish and shellfish (without degrading the flavor in the case of edible fish and shellfish).

Further, in the above-described inactivation method, OH radicals are generated from moisture contained in the surface of the seafood by irradiating the surface of the seafood with the ultraviolet rays, and the microorganisms and/or viruses are inactivated by the generated OH radicals. It may further comprise an activating step.
In this case, the generated OH radicals can also inactivate microorganisms and viruses. In other words, a synergistic effect is obtained between the ultraviolet rays and the OH radicals. In addition, since the OH radicals can go around to the back side of fish scales and gills, for example, the inactivation effect can be obtained even in the shaded areas that are not directly irradiated with ultraviolet rays.

Furthermore, in the above inactivation method, in the inactivation step, the surface of the living fish and shellfish may be irradiated with the ultraviolet rays.
In this case, it is possible to inactivate microorganisms and viruses adhering to the surface of the fish and shellfish without adversely affecting the living fish and shellfish. For example, live fish sold in fresh food stores and restaurants, and fish displayed in aquariums, etc., which humans have the opportunity to come into contact with with their bare hands, can spread harmful microorganisms and It can reduce the risk of being infected with viruses.

Moreover, in the above-described inactivation method, in the inactivation step, the surface of the non-living fish and shellfish may be irradiated with the ultraviolet rays.
In this case, microorganisms and viruses adhering to the surface of fish and shellfish can be inactivated without adversely affecting non-living fish and shellfish. As a result, for example, harmful microorganisms and viruses can be transmitted to humans through non-living seafood that people have the opportunity to touch with their bare hands, such as frozen fish and live fish sold at fresh food stores and restaurants. can reduce the risk of infection with

Furthermore, in the above-described inactivation method, in the inactivation step, the surface of the fish and shellfish on which at least one of a body surface mucilage and scales is present may be irradiated with the ultraviolet rays.
In this case, the ultraviolet rays in the above wavelength range are absorbed by body surface mucilages (so-called slime) and scales composed of protein components, and do not penetrate into the fish and shellfish. Microorganisms and viruses can be appropriately inactivated.

In the inactivation method described above, the surface of the seafood may be irradiated with the ultraviolet rays in the atmosphere in the inactivation step.
In this case, it is possible to appropriately inactivate microorganisms and viruses adhering to the surface of seafood, such as in baskets at markets and processing plants, on conveyors for transportation, and on workbenches (for example, on cutting boards).

Furthermore, in the above inactivation method, in the inactivation step, the surface of the fish and shellfish present in water may be irradiated with the ultraviolet rays through the water.
In this case, for example, it is possible to appropriately inactivate microorganisms and viruses adhering to the surface of fish and shellfish in an aquarium.

Further, one aspect of the inactivation device according to the present invention is an inactivation device that emits ultraviolet rays to inactivate microorganisms and/or viruses, and has a wavelength of 200 nm or more and 240 nm, which is absorbed by protein components on the surface of fish and shellfish. A light source unit having a light source that emits the following ultraviolet rays, and a support that supports the light source unit so as to irradiate the surface of the fish and shellfish with the ultraviolet rays emitted from the light source.

In this way, by irradiating the surface of the fish and shellfish with ultraviolet rays having a wavelength of 200 nm or more and 240 nm or less, it is possible to inactivate microorganisms and viruses adhering to the surface of the fish and shellfish. Here, the ultraviolet rays with a wavelength of 200 nm or more and 240 nm or less are ultraviolet rays that do not generate ozone, are absorbed by the protein components on the surface of the fish and shellfish, and do not penetrate inside the fish and shellfish. Therefore, it is possible to inactivate microorganisms and viruses on the surface of fish and shellfish without generating ozone and without damaging the fish and shellfish (without degrading the flavor in the case of edible fish and shellfish).

Further, in the deactivation device described above, the light source unit includes a housing containing the light source therein and having a light emission window for emitting at least part of the light emitted from the light source, and may be provided with an optical filter that transmits ultraviolet rays with a wavelength of 200 nm or more and 240 nm or less and blocks transmission of UV-C waves with wavelengths longer than 240 nm.
In this case, it is possible to irradiate only light in a wavelength range that has little adverse effect on fish and shellfish, human bodies, and animals.

INDUSTRIAL APPLICABILITY According to the present invention, microorganisms and viruses that are harmful to humans and animals adhering to the surface of fish and shellfish can be easily inactivated without adversely affecting the fish and shellfish.

It is a figure which shows the ultraviolet absorption spectrum of protein. It is a figure which shows an example of the application scene of the deactivation apparatus in this embodiment. It is a figure which shows another example of the application scene of the inactivation apparatus in this embodiment. It is a figure which shows another example of the application scene of the inactivation apparatus in this embodiment. It is a figure which shows another example of the application scene of the inactivation apparatus in this embodiment. It is a schematic diagram which shows the structural example of an ultraviolet irradiation unit. FIG. 4 is a schematic diagram showing another example of an ultraviolet irradiation unit;

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.
In the present embodiment, an inactivation device that irradiates fish and shellfish with ultraviolet rays in a predetermined space to inactivate microorganisms and viruses attached to the surface of the fish and shellfish will be described.
The term “inactivation” as used in the present embodiment refers to killing microorganisms or viruses (or losing their infectivity or toxicity).

Here, the space is not particularly limited. The above-mentioned space is, for example, a space in a facility such as a supermarket or other perishables department, a restaurant, a food processing plant, a market, or an aquarium, or an arbitrary space such as a space in a vehicle such as a truck, an aircraft, or a ship that transports food. can be The space may be a closed space or an open space that is not closed. Further, the space may be a space in which people do not exist, or may be a space in which people exist.
In the present embodiment, fish and shellfish to be irradiated with ultraviolet rays are fish and shellfish having scales and a body surface viscous substance generally called "slimy" on the surface. Furthermore, it is preferable that the surface of the fish and shellfish to be irradiated with ultraviolet rays is wet (the surface contains moisture).

The inactivation device in this embodiment irradiates the seafood with ultraviolet rays having a wavelength of 200 nm to 240 nm, which has little adverse effect on the seafood, and inactivates harmful microorganisms and viruses present on the surface of the seafood. .
In practice, the wavelength range of ultraviolet rays used for decontamination (sterilization) is 200 nm to 320 nm. It is common to use However, such ultraviolet rays in the wavelength region around 260 nm are strongly absorbed by nucleic acids in humans, animals, and fish and shellfish, and can have an adverse effect on humans, animals, and fish and shellfish.

FIG. 1 is a diagram showing ultraviolet absorption spectra of proteins.
As shown in FIG. 1, protein has an absorption peak at a wavelength of 200 nm, and it can be seen that ultraviolet rays are hardly absorbed at a wavelength of 240 nm or longer.
The surface of seafood (especially fish) is covered with scales composed of keratin, collagen, calcium phosphate, etc., and body surface mucilage (slimy) containing a large amount of glycoprotein, generally called mucin.

In other words, ultraviolet light with a wavelength of 240 nm or longer easily penetrates body surface mucilages and scales, which are protein components on the surface of fish and shellfish, and penetrates deep into the body surface of fish and shellfish. Therefore, the cells inside the body surface of fish and shellfish are easily damaged. On the other hand, ultraviolet rays with a wavelength of around 200 nm are absorbed by glycoproteins, which are the main components of body surface mucilage on the surface of fish and shellfish, and proteins that constitute part of scales, and do not permeate inside the body surface of fish and shellfish. Therefore, it is safe for the body surface of fish and shellfish.
In addition, ultraviolet light with a wavelength of 240 nm or more easily penetrates the skin of humans and animals, and penetrates deep into the skin. Therefore, the cells in the human skin are easily damaged. On the other hand, ultraviolet light with a wavelength of around 200 nm is absorbed by the human skin surface (for example, the stratum corneum) and does not penetrate into the skin. Therefore, it is safe for human and animal skin.

On the other hand, ultraviolet rays with a wavelength of less than 200 nm can generate ozone (O ₃ ). This is because when ultraviolet rays with a wavelength of less than 200 nm are irradiated in an oxygen-containing atmosphere, oxygen molecules are photodecomposed to generate oxygen atoms, and ozone is generated by a bonding reaction between the oxygen molecules and the oxygen atoms. be.
Therefore, it can be said that the wavelength range of 200 nm to 240 nm is a safe wavelength range for fish and shellfish, humans and animals. The safe wavelength range for fish and shellfish, humans and animals is preferably 200 nm to 237 nm, more preferably 200 nm to 235 nm, even more preferably 200 nm to 230 nm.
For example, ultraviolet rays with a wavelength of 222 nm emitted from a KrCl excimer lamp and ultraviolet rays with a wavelength of 207 nm emitted from a KrBr excimer lamp are both safe for fish, shellfish, humans, and animals, and can kill microorganisms and inactivate viruses. It is the light that can do

FIG. 2 is a diagram showing an application scene of the inactivation device in this embodiment. In FIG. 2, only the ultraviolet light source 110 and the wavelength selection filter (optical filter) 111 included in the light source section constituting the deactivation device are shown, and other configurations are omitted.
The ultraviolet light source 110 is configured to irradiate a living fish 201 that may be touched by a person with bare hands with ultraviolet rays (UV). Inactivates microorganisms, viruses, etc. that are harmful to humans and animals adhering to the surface.

The ultraviolet light source 110 emits, as the ultraviolet rays, ultraviolet rays in a wavelength range of 200 nm to 240 nm which has little adverse effect on fish and shellfish. The ultraviolet light source 110 can be, for example, a KrCl excimer lamp that emits ultraviolet rays with a central wavelength of 222 nm, or a KrBr excimer lamp that emits ultraviolet rays with a central wavelength of 207 nm.
The ultraviolet light source 110 is not limited to the excimer lamp described above, and may be an LED light source, an LD light source, or a coherent light source that converts the wavelength of laser light emitted from laser light to emit ultraviolet light in the above wavelength range. There may be.

However, depending on the ultraviolet light source, in addition to the above-mentioned ultraviolet rays with a wavelength of 200 nm to 240 nm, light containing wavelengths that are not considered safe for fish, humans, and animals may also be emitted. Therefore, in order to cut light of such wavelengths, for example, as shown in FIG. A wavelength selection filter 111 that cuts light in the region (200 nm to 280 nm) may be provided.
As a result, ultraviolet rays with a wavelength of 200 nm to 240 nm can be selected by the wavelength selection filter 111 from light including ultraviolet rays emitted from the ultraviolet light source 110, and the surface of the living fish 201 can be irradiated with the selected ultraviolet rays.
In this embodiment, the case where the deactivation device includes the wavelength selection filter 111 will be described, but the wavelength selection filter 111 may be separate from the deactivation device.

Here, the ultraviolet irradiation to the living fish 201 can be performed in the air, for example.
For seafood that is distributed alive and sent to a processing site such as a backyard, for example, in a basket, on a transport conveyor, or at a processing site (e.g., on a cutting board), ultraviolet rays (e.g., ultraviolet rays with a wavelength of 222 nm ) is irradiated in air. FIG. 2 shows an example of irradiating a fish 201 living in the atmosphere with ultraviolet light.

The ultraviolet light source 110 may control the emission timing of ultraviolet rays by a control unit 17 (see FIG. 6) described later. For example, when an irradiation area irradiated with ultraviolet rays emitted from the ultraviolet light source 110 is predetermined, detection (not shown) of a living fish 201 being placed or transferred to the irradiation area is performed. At the timing detected by the unit, the control unit 17 may control the ultraviolet light source 110 to irradiate the irradiation region with ultraviolet rays.
On the other hand, continuous irradiation of ultraviolet rays for a long period of time can adversely affect fish that can be touched by viewers in an aquarium. Therefore, for such ornamental fish, the control unit 17 controls the ultraviolet light source 110 to irradiate the irradiation area with ultraviolet rays at the timing when the detection unit (not shown) detects the approach of the viewer. can be

As described above, in the present embodiment, the ultraviolet light source 110 emits ultraviolet light having a wavelength of 200 nm or more and 240 nm or less that is absorbed by the protein component on the surface of the fish and shellfish, and the ultraviolet light emitted from the ultraviolet light source 110 is applied to the fish and shellfish. Microorganisms and/or viruses present on the surface of the seafood are inactivated by irradiating the surface protein components.
In this way, by irradiating the seafood with ultraviolet rays, even if microorganisms and viruses harmful to humans are attached to the surface of the seafood before it comes into contact with humans, the microorganisms and viruses can be removed before humans come into contact with them. can be inactivated to Therefore, it is possible to reduce the risk of humans being infected with harmful microorganisms and viruses through seafood. In other words, it is possible to block the route of infection from fish and shellfish to humans.

Also, at distribution sites, etc., unspecified people (animals in some cases) come into contact with live seafood. In this case, harmful microorganisms and viruses of human and animal origin may adhere to the surface of the seafood. Furthermore, even if a person does not come into contact with seafood, if harmful microorganisms or viruses are contained in the droplets emitted from a person by talking, sneezing, or exhaling, the droplets will adhere to the surface of the seafood, Harmful microorganisms and viruses adhere to the surface of seafood.
In these cases as well, by irradiating the fish and shellfish with ultraviolet rays in the manner described above, it is possible to reduce the risk of humans being infected with harmful microorganisms and viruses derived from humans and animals through the fish and shellfish. can. In other words, it is possible to block the route of infection from humans (or animals) to fish and shellfish to humans.

In addition, in this embodiment, in order to inactivate harmful microorganisms and viruses present on the surface of living fish and shellfish, the fish and shellfish are irradiated with ultraviolet light having a wavelength of 200 nm to 240 nm, which is absorbed by protein components. The surface of living fish (fish and shellfish) is covered with scales containing protein and body surface mucilage (slimy). It can be made to act only on the surface of fish and shellfish without permeating ultraviolet rays. Therefore, it is possible to inactivate microorganisms and viruses present on the surface of fish and shellfish without damaging the inside of the fish and shellfish. The term "damage" as used herein includes threatening the survival of seafood, impairing the flavor of seafood, and the like.

During the work of irradiating the surface of fish and shellfish with ultraviolet rays, part of the irradiated ultraviolet rays may be diffusely reflected by the workbench on which the fish and shellfish are held and the surrounding articles, and the operator may be irradiated with the ultraviolet rays. However, as described above, ultraviolet rays with a wavelength of 200 nm to 240 nm are in principle safe for humans, and there is no problem even if the skin and eyes of workers are irradiated as long as the allowable irradiation dose is not exceeded. .
As described above, the illuminance of the ultraviolet rays that are irregularly reflected and irradiated to the worker is relatively small, and the ultraviolet irradiation time during the work is not so long. Therefore, during normal work, the dose of ultraviolet rays to humans (workers) rarely reaches the permissible dose. Therefore, even in a space where people are present, the deactivation treatment by ultraviolet irradiation can be performed safely for people.

Further, the UV irradiation to the fish and shellfish may be performed in a state where the surface of the fish and shellfish is wet with water.
Wetting the surface of the fish with moisture keeps the slime continuous (prevents cracking), maintains the film thickness of the slime, and suppresses the curling up, chipping, and cracking of the scales due to drying. Therefore, it is possible to appropriately absorb ultraviolet rays with a wavelength of 200 nm to 240 nm on the surface of fish and shellfish.
Furthermore, when water is irradiated with ultraviolet rays having a wavelength of 222 nm, OH radicals (hydroxyl radicals) are generated. When the surface of the fish is wet, OH radicals can be generated from the moisture on the surface of the fish by irradiating ultraviolet rays with a wavelength of 222 nm. This OH radical greatly contributes to the inactivation of microorganisms and viruses on the surface of fish and shellfish. In other words, a synergistic effect can be expected in that the combination of ultraviolet rays with a wavelength of 222 nm and OH radicals can inactivate microorganisms and viruses. In addition, since the OH radicals can go around to the back side of fish scales and gills, for example, the inactivation effect can be obtained even in the shaded areas that are not directly irradiated with ultraviolet rays.

Note that FIG. 2 shows an example in which a live fish 201 is targeted for irradiation with ultraviolet rays, but the target for irradiation with ultraviolet rays may be a non-living fish. In this case, the targets to be irradiated with ultraviolet rays are, for example, fish and shellfish that are distributed for sale, eating and drinking, etc., and include fish that have been frozen during transportation, fish that are not yet alive before being processed, and the like.
For example, as shown in FIG. 3, the surface of a non-living fish 202 placed on a chopping board 311 is irradiated with ultraviolet rays (UV) emitted from an ultraviolet light source 110 and transmitted through a wavelength selection filter 111. may

Moreover, when the cutting board 311 is made of a material that transmits ultraviolet rays, the cutting board 311 can be irradiated with ultraviolet rays from below as shown in FIG. In this case, for example, the ultraviolet light source 110 can be arranged inside the work table on which the cutting board 311 is placed, and the ultraviolet light can be irradiated through the ultraviolet transmission window including the wavelength selection filter 111 provided in the work table.

It should be noted that the ultraviolet irradiation of non-living fish 202 is not limited to being performed on the chopping board 311 . As with live fish 201 described above, non-live fish 202 can also be irradiated with UV light, for example, in baskets at markets or processing plants or on transport conveyors. Alternatively, the fish 202 wrapped in an ultraviolet-transmitting wrap film or the like may be irradiated with ultraviolet rays.
Fish caught in coastal waters and coastal waters are stored in steel boxes or the like together with crushed ice, and transported alive to supermarkets and other perishable food stores and restaurants. Such non-living fish may be irradiated with ultraviolet light prior to processing at fresh food counters or restaurants.
In order to maintain freshness, fish caught by deep-sea fishing are pre-processed (the tail, gills, internal organs, etc. are removed and the blood is removed), then flash-frozen and stored in a freezer warehouse. . Such non-living fish may be irradiated with ultraviolet light prior to trading, for example, auctions.

Even with non-live seafood packed in steel boxes or frozen, during distribution, unspecified people may touch it with their bare hands, or droplets from people may adhere to the surface. Harmful microorganisms and viruses may adhere. However, by irradiating non-living fish and shellfish with ultraviolet rays by the above-described method, the harmful microorganisms and viruses can be appropriately inactivated, and humans can be exposed to harmful human-derived It can reduce the risk of infection with harmful microorganisms and viruses.
In addition, the influence of diffusely reflected ultraviolet rays on the worker during the ultraviolet irradiation work poses almost no problem, as in the case of the living fish 201 described above.

Here, when irradiating non-living seafood (fish) with ultraviolet rays, it is preferable to irradiate the surface with ultraviolet rays in a state in which scales and body surface mucilage (slimy) on the surface of the seafood are not removed.
When the surface of seafood is irradiated with ultraviolet rays after the scales and viscous substances on the body surface have been removed, the edible portion of the seafood is directly irradiated with the ultraviolet rays. It may change and lose its value as food.

Furthermore, the ultraviolet irradiation to seafood such as fish 201 and 202 may be performed through water, for example. In this case, the object to be irradiated with ultraviolet rays is a fish in a tank during transportation, a fish tank at a destination, a fish tank in an aquarium, or the like.
For example, as shown in FIG. 5, ultraviolet rays (UV) emitted from an ultraviolet light source 110 and transmitted through a wavelength selection filter 111 are irradiated to the surface of a living fish 201 through water 322 in a water tank 321. may Further, the water tank 321 may be in a state of being loaded on a loading platform 331 of a truck, which is transportation means (moving means), as shown in FIG.

The ultraviolet light source 110 is arranged above the water tank 321 and emits ultraviolet rays (UV) downward. This ultraviolet light source 110 may be installed on the track or may be installed in the water tank 321 .
In addition, the arrangement position of the ultraviolet light source 110 is not limited to the position shown in FIG. The ultraviolet light source 110 may be arranged, for example, on the side of the water tank 321 or may be arranged below the water tank 321 .

Also, the number of ultraviolet light sources 110 is not limited to one. For example, a plurality of ultraviolet light sources 110 may be arranged for one water tank 321 to irradiate the water tank 321 with ultraviolet rays from different directions. In this case, even when a large number of fish 201 are placed in the water tank 321, the ultraviolet rays are blocked by the fish 201 positioned closer to the ultraviolet light source 110 in the water tank 321 (upper side in FIG. 5). It is possible to prevent the fish 201 located on the far side (lower side in FIG. 5) from the light source 110 from not being irradiated with ultraviolet rays.

FIG. 6 is a schematic diagram showing a configuration example of an inactivation device.
FIG. 6 shows an ultraviolet irradiation unit 10, which is a part related to ultraviolet irradiation of the light source, and a support 21 that supports the light source.
The ultraviolet irradiation unit 10 includes, for example, a housing 11 made of conductive metal, and an ultraviolet light source 12 housed inside the housing 11 .
The ultraviolet light source 12 corresponds to the ultraviolet light source 110 described above, and can be, for example, a KrCl excimer lamp that emits ultraviolet light with a central wavelength of 222 nm. The ultraviolet light source 12 is not limited to the KrCl excimer lamp, and may be any light source that emits ultraviolet light within a wavelength range of 200 nm to 240 nm.
The support 21 supports the light source part so as to irradiate the surface of the fish and shellfish with ultraviolet rays emitted from the ultraviolet light source (excimer lamp) 12 . For example, the support 21 is attached to a ceiling, wall, or other structure to support the light source.

Further, the ultraviolet irradiation unit 10 includes a power supply section 16 that supplies power to the excimer lamp 12, and a control section 17 that controls irradiation and non-irradiation of the excimer lamp 12, the amount of ultraviolet light emitted from the excimer lamp 12, and the like. . The excimer lamp 12 is supported by a support portion 18 inside the housing 11 .
Here, the support portion 18 may be, for example, a vibration isolation member. By supporting the excimer lamp 12 by the vibration isolating member 18, the excimer lamp 12 can be suppressed from being affected by vibration, and can be stably irradiated with ultraviolet rays. For example, as shown in FIG. 5, when the fish 201 in the water tank 321 loaded on the truck bed 331 is irradiated with ultraviolet rays, and the light source unit is installed on the truck, the excimer lamp 12 is turned on when the truck moves. vibrate inside. Thus, even when vibration is applied to the ultraviolet irradiation unit 10 (excimer lamp 12) during movement of the moving means, the excimer lamp 12 can stably emit ultraviolet rays.

The housing 11 is formed with an opening 11a serving as a light exit window. A window member 11b is provided in the opening 11a. The window member 11b can include, for example, an ultraviolet transmitting member made of quartz glass, an optical filter corresponding to the above-described wavelength selection filter 111 for blocking unnecessary light, and the like.
A plurality of excimer lamps 12 can also be arranged in the housing 11 . The number of excimer lamps 12 is not particularly limited. Also, the configuration of the excimer lamp 12 is not particularly limited.

As the optical filter, for example, a wavelength selection filter that transmits light in the wavelength range of 200 nm to 230 nm and cuts light in the other UV-C wavelength range (light of 231 nm to 280 nm) can be used.
Here, as the wavelength selection filter, for example, a dielectric multilayer filter with HfO ₂ layers and SiO ₂ layers can be used.
As the wavelength selection filter, an optical filter having a dielectric multilayer film of SiO ₂ layers and Al ₂ O ₃ layers can also be used.
By providing the optical filter in the light exit window in this way, even if the excimer lamp 12 emits light that is harmful to humans, it is possible to more reliably prevent the light from leaking out of the housing 11. can be reduced to

In addition, since the excimer lamp performs high-frequency lighting when high-frequency power is applied, high-frequency noise is generated. However, by forming the housing 11 containing the excimer lamp from a conductive metal as described above, it is possible to suppress transmission of high-frequency noise from the excimer lamp to the outside of the housing 11 . As a result, the control command to another control system installed in the vicinity of the ultraviolet irradiation unit 10 can be prevented from being disturbed by the high-frequency noise, and the control command can be prevented from malfunctioning. can.

In addition, in the above embodiment, the case of using an excimer lamp as an ultraviolet light source has been described, but an LED can also be used as an ultraviolet light source.
As the LED, for example, an aluminum gallium nitride (AlGaN)-based LED, an aluminum nitride (AlN)-based LED, a magnesium zinc oxide (MgZnO)-based LED, or the like can be employed.
Here, for the AlGaN-based LED, it is preferable to adjust the Al composition so that the center wavelength is within the range of 190 nm to 235 nm. AlN-based LEDs emit ultraviolet rays with a peak wavelength of 210 nm. Also, the MgZnO-based LED can emit ultraviolet light with a center wavelength of 222 nm by adjusting the composition of Mg.
FIG. 7 shows an example of an ultraviolet irradiation unit 10 using an LED 19 as an ultraviolet light source. In FIG. 7, the ultraviolet irradiation unit 10 is provided with a plurality of LEDs 19. As shown in FIG.

As described above, the wavelength range of ultraviolet rays used for decontamination (sterilization) is from 200 nm to 320 nm, and a particularly effective wavelength is around 260 nm where nucleic acids (DNA, RNA) absorb strongly.
Therefore, the LED 19 as the ultraviolet light source mounted on the ultraviolet irradiation unit 10 also employs one that emits ultraviolet rays with a wavelength of 200 nm to 320 nm. Specifically, for example, an aluminum gallium nitride (AlGaN)-based LED, an aluminum nitride (AlN)-based LED, or the like can be employed. AlGaN-based LEDs emit light in the deep UV region (DUV) in the wavelength range of 200 nm to 350 nm by changing the composition of aluminum (Al). AlN-based LEDs emit ultraviolet rays with a peak wavelength of 210 nm.

Here, for the AlGaN-based LED, it is preferable to adjust the Al composition so that the center wavelength is within the range of 200 nm to 237 nm. As described above, ultraviolet rays in this wavelength range are safe for humans and animals, and can appropriately sterilize microorganisms and inactivate viruses. For example, by adjusting the composition of Al, it is possible to produce an AlGaN-based LED emitting ultraviolet rays with a central wavelength of 222 nm.

A magnesium zinc oxide (MgZnO) LED can also be employed as the LED. MgZnO-based LEDs emit light in the deep UV region (DUV) in the wavelength range of 190 nm to 380 nm by changing the composition of magnesium (Mg).

Here, for the MgZnO-based LED, it is preferable to adjust the composition of Mg so that the center wavelength is within the range of 200 nm to 237 nm.
As described above, ultraviolet rays in this wavelength range are safe for humans and animals, and can appropriately sterilize microorganisms and inactivate viruses. For example, by adjusting the composition of Mg, it is possible to obtain an MgZnO-based LED emitting ultraviolet rays with a central wavelength of 222 nm.

Here, an LED that emits ultraviolet rays (especially ultraviolet rays in the deep ultraviolet region) as described above has a low luminous efficiency of several percent or less and generates a large amount of heat. Further, when the heat generated by the LED increases, the intensity of the light emitted from the LED decreases, and the wavelength of the emitted light also shifts. Therefore, in order to suppress the heat rise of the LED, it is preferable to install the LED 19 on a cooling member (for example, heat radiating fins for radiating heat) 20 as shown in FIG.
At this time, a part of the cooling member 20 may protrude from the housing 11 of the ultraviolet irradiation unit 10, as shown in FIG. In this case, part of the cooling member 20 is exposed to outside air, and the heat dissipation of the cooling member 20 progresses efficiently.

The AlGaN-based LED and the MgZnO-based LED, which emit ultraviolet rays with a central wavelength of 222 nm, emit ultraviolet rays in a wavelength range that spreads to some extent from the central wavelength of 222 nm, and the light emitted from the LEDs contains a small amount of human energy. and UV wavelengths that are unsafe for animals. Therefore, as in the case where the ultraviolet light source is an excimer lamp, it is preferable to use a dielectric multilayer filter (optical filter) that cuts light in the UV-C wavelength range having wavelengths other than the wavelength range of 200 nm to 230 nm.

However, the above-mentioned AlN-LED emitting ultraviolet rays with a center wavelength of 210 nm does not require the above-mentioned optical filter.
Also, whether the ultraviolet light source is an excimer lamp or an LED, depending on the illuminance on the light emitting surface of the ultraviolet light source, the distance from the ultraviolet light source to the surface to be irradiated with ultraviolet rays, etc. and animal-unsafe wavelengths of UV light may fall below the permissible level. Therefore, in such a case, it is not necessary to provide the optical filter.

According to the inactivation device and the inactivation method according to the present invention, it is possible to provide the original sterilization and virus inactivation capabilities of ultraviolet rays without adversely affecting fish and shellfish and the human body due to ultraviolet irradiation. In particular, unlike conventional inactivation devices and inactivation methods, effective sterilization and inactivation by ultraviolet rays can be performed even in a space where people are present. This corresponds to Goal 3 of the United Nations-led Sustainable Development Goals (SDGs), "Ensure healthy lives and promote well-being for all at all ages", and also to Target 3.3. It will make a significant contribution to “by 2030, end epidemics such as AIDS, tuberculosis, malaria and neglected tropical diseases, and combat hepatitis, water-borne diseases and other communicable diseases”.

DESCRIPTION OF SYMBOLS 10... Ultraviolet irradiation unit, 11... Housing, 12... Excimer lamp, 16... Power supply part, 17... Control part, 18... Support part, 19... LED, 20... Cooling member, 21... Support body, 110... Ultraviolet light source, 111... Wavelength selection filter, 201... Living fish, 202... Non-living fish

Claims (9)

A step of radiating, from a light source, ultraviolet rays having a wavelength of 200 nm or more and 240 nm or less, which are absorbed by the protein components on the surface of the fish and shellfish;
and irradiating the protein component on the surface of the seafood with the ultraviolet rays emitted from the light source to inactivate microorganisms and/or viruses present on the surface of the seafood. activation method. The method further comprises a step of irradiating the surface of the fish and shellfish with the ultraviolet rays to generate OH radicals from water contained in the surface of the fish and shellfish, and inactivating the microorganisms and/or viruses by the generated OH radicals. The inactivation method according to claim 1, wherein In the inactivating step,
3. The inactivation method according to claim 1, wherein the surface of the living fish and shellfish is irradiated with the ultraviolet rays. In the inactivating step,
3. The inactivation method according to claim 1 or 2, wherein the surface of the non-living fish and shellfish is irradiated with the ultraviolet rays. In the inactivating step,
3. The inactivation method according to claim 1 or 2, wherein the ultraviolet rays are applied to the surface of the fish and shellfish on which at least one of body surface viscous substances and scales are present. In the inactivating step,
3. The inactivation method according to claim 1, wherein the surface of the fish and shellfish is irradiated with the ultraviolet rays in the atmosphere. In the inactivating step,
3. The inactivation method according to claim 1, wherein the surface of the fish and shellfish existing in water is irradiated with the ultraviolet rays through the water. An inactivation device that emits ultraviolet rays to inactivate microorganisms and/or viruses,
a light source unit having a light source that emits ultraviolet light with a wavelength of 200 nm or more and 240 nm or less that is absorbed by the protein component on the surface of the fish and shellfish;
and a support for supporting the light source unit so as to irradiate the surface of the fish and shellfish with the ultraviolet rays emitted from the light source. The light source unit includes a housing that houses the light source and has a light exit window that emits at least part of the light emitted from the light source,
8. The light exit window is provided with an optical filter that transmits ultraviolet rays having a wavelength of 200 nm or more and 240 nm or less and blocks transmission of UV-C waves having a wavelength longer than 240 nm. The inactivation device according to .

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