Sterilization system and beverage manufacturing method

Abstract

This method reduces greenhouse gas emissions while sterilizing drinking water without affecting its mineral content. [Solution] A sterilization system for sterilizing drinking water in a way that does not affect the mineral components contained in drinking water, such as natural water, natural mineral water, or mineral water, comprises a sterilization device having a chamber through which the drinking water flows and an irradiation device that irradiates the drinking water flowing in the chamber with ultraviolet light, wherein the equivalent ultraviolet irradiation dose of the ultraviolet light irradiated onto the drinking water in the chamber is 128.0 mJ / cm². 2 That's all.

Description

[Technical Field]

[0001] This invention relates to a sterilization system for sterilizing drinking water in a manner that does not affect the mineral components contained in the drinking water. Furthermore, this invention relates to a method for producing beverages by sterilizing drinking water in a manner that does not affect the mineral components contained in the drinking water. [Background technology]

[0002] Patent Document 1 discloses a contents filling system equipped with a water sterilization line for non-heating sterilization of pure water. This water sterilization line comprises a first water tank and a water sterilizer. The water sterilizer sterilizes the pure water stored in the first water tank without heating. The water sterilizer also comprises a first sterilizer, a first sterile filter, a second sterilizer, and a second sterile filter. The first sterilizer also has an ultraviolet irradiation unit located within its main body.

[0003] This ultraviolet irradiation unit includes a first ultraviolet lamp and a second ultraviolet lamp. The first sterilizer sterilizes bacteria that have passed through the foreign matter removal filter using ultraviolet light. Furthermore, Patent Document 1 states that the cumulative irradiation dose of ultraviolet light to water is 10 mJ / cm². 2 More than 10000mJ / cm 2 Preferably, it is 100 mJ / cm². 2 More than 10000mJ / cm 2 It is stated that the following is preferable. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-059188 [Overview of the project] [Problems that the invention aims to solve]

[0005] To reduce emissions of greenhouse gases such as carbon dioxide and methane, it is conceivable to adopt a non-heating sterilization system using ultraviolet light, as described in Patent Document 1, instead of conventional heat sterilization systems. However, there are challenges when irradiating natural water, natural mineral water, or mineral water (hereinafter also referred to as drinking water) with ultraviolet light. Specifically, irradiating these drinking waters with ultraviolet light may affect the mineral content of the drinking water. Therefore, the inventors of the present invention have found conditions under which the mineral content is not affected. As a result, it is possible to reduce greenhouse gas emissions and sterilize drinking water without affecting the mineral content. [Means for solving the problem]

[0006] A sterilization system according to one embodiment is a sterilization system for sterilizing drinking water, such as natural water, natural mineral water, or mineral water, in a manner that does not affect the mineral components contained in the drinking water. The sterilization apparatus comprises a chamber through which the drinking water flows, and an irradiation device that irradiates the drinking water flowing in the chamber with ultraviolet light. The equivalent ultraviolet radiation dose irradiated onto the drinking water in the chamber is 128.0 mJ / cm². 2 That's all.

[0007] Furthermore, another embodiment of the beverage manufacturing method is a beverage manufacturing method that sterilizes drinking water in such a way as not affecting the mineral components contained in drinking water that is natural water, natural mineral water, or mineral water, and manufactures a beverage, The drinking water is poured into the chamber. The drinking water flowing through the chamber is irradiated with ultraviolet light by an irradiation device. The equivalent ultraviolet radiation dose irradiated onto the drinking water in the chamber is 128.0 mJ / cm². 2 That's all. [Brief explanation of the drawing]

[0008] [Figure 1] Block diagram of the manufacturing system. [Figure 2] A graph showing the test results for measuring UV resistance. [Figure 3] An explanatory diagram describing an ultraviolet irradiation device. [Figure 4] A table showing the test results for measuring the UV resistance of indicator bacteria. [Figure 5] A table showing the test results for measuring the UV resistance of MS2. [Figure 6] An explanatory diagram describing the test line. [Figure 7] A table showing the test conditions for the water flow test and the measurement results of the permeability of the test liquid. [Figure 8] A table showing the results of the water flow test. [Figure 9] Distribution map of ultraviolet radiation exposure to virtual particles. [Figure 10] A table comparing REDreal and REDCFD. [Figure 11] An explanatory diagram describing the irradiation test apparatus. [Figure 12] A shows sample creation result 1, and B shows sample creation result 2. [Figure 13] A table showing the results of the analytical tests. [Modes for carrying out the invention]

[0009] Hereinafter, exemplary embodiments for carrying out the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, and relative positions of components described in the following embodiments can be arbitrarily set and modified according to the configuration of the apparatus or method to which the present invention is applied, or according to various conditions. Furthermore, unless otherwise specified, the scope of the present invention is not limited to the embodiments specifically described below.

[0010] In this specification, drinking water refers to water suitable for drinking, including natural water, natural mineral water, or mineral water. Beverages refer to liquid beverages that are filled into containers such as soft drinks. Beverages can be drinking water itself, drinking water that has undergone physical or chemical treatment, or drinking water mixed with other substances (e.g., carbon dioxide, sodium, calcium, magnesium, and potassium). Furthermore, beverages may be liquids manufactured using sterilized drinking water as a raw material. In this specification, "up" refers to the upper side in the direction of gravity, and "down" refers to the lower side in the direction of gravity.

[0011] Furthermore, not affecting the mineral content means that the mineral content in the drinking water is not substantially reduced. More specifically, not affecting the mineral content means that at least one of the following is not substantially reduced: calcium carbonate (CaCO3), silicon dioxide (SiO2), calcium (Ca), and magnesium (Mg). As an example, if 90% (more preferably 95%) of the mineral content before sterilization remains in the drinking water after sterilization, the mineral content is considered not to have been substantially reduced.

[0012] Natural water is groundwater collected from a specific, single source. This natural water undergoes no physical or chemical treatment other than sedimentation, filtration, and heat sterilization. Natural mineral water is a type of natural water that has been mineralized. This natural mineral water undergoes no physical or chemical treatment other than sedimentation, filtration, and heat sterilization. Mineral water is a type of natural water that has been mineralized. This mineral water may undergo treatments such as mineral adjustment, aeration, or blending of natural mineral water collected from multiple sources.

[0013] [Embodiment] Referring to Figure 1, a manufacturing system 100 for producing beverages by sterilizing drinking water will be described. Figure 1 is a block diagram illustrating the manufacturing system 100. In this manufacturing system 100, drinking water is sterilized in a way that does not affect the mineral components contained in the drinking water.

[0014] Furthermore, each device and each tank specified as part of the configuration of the manufacturing system 100, as well as other devices included in the manufacturing system 100 (e.g., measuring devices), are connected to a fluid supply route, such as drinking water or raw water. This supply route is, for example, composed of piping through which the fluid flows. However, a portion of the supply route may include a route through which the fluid is transported manually by workers managing and operating the manufacturing system 100, or by a fluid transport device. In addition, each device, each tank, and other device may be one or multiple. Moreover, each device, each tank, and other device may function independently or as a unit that functions together with other machinery or structures.

[0015] The manufacturing system 100 includes a raw water tank 10, a flow meter 20, a sterilization device 30, a filter 40, a storage tank 50, a filling device 60, and a control device 70. The manufacturing system 100 also includes a sterilization system 101 for sterilizing drinking water in a way that does not affect the mineral components contained in the drinking water. For example, the sterilization system 101 includes a flow meter 20, a sterilization device 30, and a filter 40, etc. However, the sterilization system 101 may include other devices or tanks. For example, the sterilization system 101 may include the raw water tank 10 or the storage tank 50, etc.

[0016] The raw water tank 10 stores raw water that will be used as the raw material for drinking water. For example, the raw water is groundwater drawn from underground. The raw water may include groundwater drawn from a specific single source, mineralized groundwater, and water obtained by mixing groundwater drawn from multiple sources. There may be multiple raw water tanks 10, and raw water from different sources may be stored in multiple raw water tanks 10.

[0017] The flow meter 20 measures the flow rate of raw water sent from the raw water tank 10 to the sterilization device 30. For example, the flow meter 20 measures the flow rate of raw water flowing through a pipe. The flow meter 20 is also connected to the control device 70 by wire or wireless connection. As an example, the flow meter 20 may be an electromagnetic flow meter, an ultrasonic flow meter, a differential pressure flow meter, or a mass flow meter.

[0018] Furthermore, the manufacturing system 100 is equipped with a flow control valve that is wired or wirelessly connected to the control device 70. The flow control valve is an automatic control valve, and the control device 70 controls the valve opening of the flow control valve based on the measurement value from the flow meter 20. For example, the control device 70 controls the flow rate of raw water sent to the sterilization device 30 to a predetermined amount (for example, 35 m³). 3 The valve opening of the flow control valve is controlled so that it becomes ( / h).

[0019] The sterilization device 30 has a chamber 31C through which drinking water flows. The sterilization device 30 also has an ultraviolet lamp 32 as an example of an irradiation device for irradiating the drinking water flowing in the chamber 31C with ultraviolet light. The sterilization device 30 also has an ultraviolet intensity meter 33 (for example, "CUVS-AFX-1" manufactured by Chiyoda Kohan Co., Ltd.). For example, the chamber 31C has an inlet 31A through which drinking water flows in and an outlet 31B through which drinking water flows out. Drinking water flows into the chamber 31C from the inlet 31A at the bottom. The drinking water that has flowed into the chamber 31C then flows out from the outlet 31B at the top after passing through the chamber 31C.

[0020] The chamber 31C is cylindrical, and its inner surface is configured to reflect ultraviolet light. For example, the chamber 31C is made of stainless steel. The chamber 31C may also be a straight pipe or a bent pipe. For example, the chamber 31C may be a straight pipe with the inlet 31A and outlet 31B located coaxially. Drinking water may temporarily remain in the chamber 31C.

[0021] A UV lamp 32 and a UV intensity meter 33 are arranged inside the chamber 31C. For example, the UV lamp 32 is housed in a liquid-tight protective tube (for example, a quartz sleeve) and placed inside the chamber 31C. For example, six UV lamps 32 are arranged inside the chamber 31C. However, the number of UV lamps 32 may be more or less than six. The UV lamp 32 may also be a low-pressure mercury lamp, a low-pressure high-power amalgam lamp, or a medium-pressure mercury lamp. Alternatively, the irradiation device may be a UV LED (Deep UV Light-Emitting Diode). In the following description, an example in which the UV lamp 32 is a low-pressure high-power amalgam lamp will be mainly described.

[0022] The ultraviolet light emitted from the ultraviolet lamp 32 contains a wavelength component of 254 nm. However, the ultraviolet light emitted from the ultraviolet lamp 32 may also contain wavelength components shorter or longer than 254 nm. For example, the ultraviolet light emitted from the ultraviolet lamp 32 may contain wavelength components between 200 nm and 280 nm.

[0023] For example, the ultraviolet intensity meter 33 is positioned within the chamber 31C, surrounded by six ultraviolet lamps 32 arranged at equal intervals in a circular pattern. The ultraviolet intensity meter 33 is located near the center of the chamber 31C. The ultraviolet lamps 32 and the ultraviolet intensity meter 33 extend along the direction of extension of the chamber 31C. The direction of extension of the chamber 31C is also the direction in which the drinking water flows. Therefore, the ultraviolet lamps 32 and the ultraviolet intensity meter 33 extend in the direction in which the drinking water flows. Alternatively, the ultraviolet intensity meter 33 may be located in the upper or lower part of the chamber 31C.

[0024] Furthermore, the equivalent ultraviolet radiation dose irradiated onto the drinking water in chamber 31C is 128.0 mJ / cm². 2The above is the case. This converted UV irradiation dose represents the amount of UV light received by drinking water and the microorganisms contained therein while passing through Chamber 31C, in terms of the sterilization ability or inactivation ability with respect to the microorganisms. Also, the converted UV irradiation dose may be 133.5 mJ / cm 2 or more. As an example, these converted UV irradiation doses can be adopted when sterilizing microorganisms of the genus Methylobacterium, particularly Methylobacterium radiotolerans. However, these converted UV irradiation doses can also be adopted when sterilizing other microorganisms. In particular, these converted UV irradiation doses can be adopted when sterilizing microorganisms having UV resistance comparable to these microorganisms.

[0025] Furthermore, the converted UV irradiation dose may be 4042.0 mJ / cm 2 or less, or 400.8 mJ / cm 2 or less. Thereby, drinking water belonging to mineral waters can be sterilized without affecting the mineral components. Also, the sterilization device 30 sterilizes by irradiating UV light instead of heat sterilization. Therefore, when sterilizing drinking water, the emission amount of greenhouse gases can be reduced.

[0026]

[0027] As an example, the converted UV irradiation dose is determined as the UV irradiation dose in the sterilization device 30 according to the method described in Appendix B of ISO 20468-4. As another example, the converted UV irradiation dose is determined as the UV irradiation dose in the sterilization device 30 according to the method described in Appendix C of ISO 20468-4.Filter 40 is a sterilization filter that captures microorganisms such as Escherichia coli and Enterococcus and filters drinking water. In other words, filter 40 removes microorganisms contained in drinking water as it passes through it. Filter 40 through which drinking water passes has a pore size of 0.1 μm or more and 0.22 μm or less. However, the pore size of filter 40 can be arbitrarily set depending on the size of the microorganisms to be removed. For example, filter 40 with a pore size of 0.1 μm can remove microorganisms of the genus Mycoplasma. Multiple filters 40 with the same pore size may be provided, or multiple filters 40 with different pore sizes may be provided.

[0028] The storage tank 50 stores the drinking water filtered by the filter 40 as beverage. This storage tank 50 functions as a buffer tank for temporarily storing the beverage. If other substances (e.g., carbon dioxide and sodium) are mixed with the drinking water, the storage tank 50 stores the beverage produced by mixing the other substances. The filling device 60 then fills the beverage supplied from the storage tank 50 into containers. Examples of containers include cans, barrels, plastic bottles, paper containers, glass bottles, and pouch containers.

[0029] The control device 70 is configured as a computer combining a processor that performs various calculations and operation controls according to a predetermined program, and other peripheral devices. The control device 70 controls the entire manufacturing system 100, or at least one of the devices and parts of the manufacturing system 100. For example, a flow control valve is placed in the supply line between the flow meter 20 and the sterilization device 30. The control device 70 obtains the flow rate of raw water from the flow meter 20 and controls the valve opening of the flow control valve so that the flow rate of raw water sent to the sterilization device 30 becomes a predetermined amount.

[0030] As an example, the control device 70 has a processor and a memory that stores a control program. The processor is, for example, a CPU (Central Processing Unit) or an MPU (Micro-Processing Unit), and comprehensively controls various processes based on the program stored in the memory. The control device 70 may also have an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). The memory includes RAM (Random Access Memory), which is the system work memory for the processor to operate, and storage devices such as ROM (Read Only Memory), HDD (Hard Disk Drive), and SSD (Solid State Drive) that store programs and system software.

[0031] Furthermore, the control device 70 is connected via wired or wireless connection to an operating device including a keyboard or various switches for inputting predetermined commands and data. The control device 70 is also connected via wired or wireless connection to a display device that shows the device's input status, setting status, measurement results, and various other information. In addition, the control device 70 can perform control according to programs stored on portable recording media such as CDs (Compact Discs), DVDs (Digital Versatile Discs), CF (Compact Flash) cards, and USB (Universal Serial Bus) memory, or on external storage media such as servers on the Internet.

[0032] [Converted UV irradiation amount] Referring to Figures 2 to 10, the converted ultraviolet irradiation dose of ultraviolet light irradiated onto drinking water in Chamber 31C will be explained. First, in order to determine the converted ultraviolet irradiation dose, an indicator microorganism was selected from among five types of Methylobacterium genus microorganisms. Then, an ultraviolet inactivation curve showing the ultraviolet resistance of the indicator microorganism was obtained. Next, the converted ultraviolet irradiation dose showing the sterilization capacity of the sterilization device 30 was determined. To do this, an ultraviolet inactivation curve showing the ultraviolet resistance of bacteriophage MS2 (hereinafter referred to as "MS2") was obtained. Then, using the ultraviolet inactivation curve of MS2, the converted ultraviolet irradiation dose was determined with water flowing through the sterilization device 30, that is, according to the method described in Appendix B of ISO20468-4 (i.e., the experimental evaluation method).

[0033] Furthermore, the equivalent UV irradiation dose was determined by performing CFD-I (Computational Fluid Dynamics-Intensity) analysis using the UV inactivation curve of MS2. Specifically, the equivalent UV irradiation dose was determined according to the method described in Appendix C of ISO20468-4 (i.e., the experimental evaluation method in combination with CFD-I simulations, hereinafter also referred to as the CFD method). It was then confirmed that the equivalent UV irradiation dose of the sterilization device 30 could be determined according to the CFD method. Subsequently, the equivalent UV irradiation dose was determined according to the CFD method using the UV inactivation curve of the indicator bacteria. This procedure will be explained in detail below.

[0034] Figure 2 is a graph showing the test results for measuring the UV resistance of microorganisms. In Figure 2, the vertical axis represents the survival rate, and the horizontal axis represents the UV irradiation dose (mJ / cm²). 2Figure 6 shows the results of the UV irradiation test. The survival rate is the ratio of the surviving concentration of microorganisms after irradiation to the initial concentration of microorganisms before irradiation. Figure 3 is an explanatory diagram of the UV irradiation device 80 used in the test. Figure 4 is a table showing the test results of measuring the UV resistance of indicator bacteria. Figure 5 is a table showing the test results of measuring the UV resistance of MS2. In Figures 4 and 5, "Log" indicates the logarithm of the survival rate. Figure 6 is an explanatory diagram of the test line in which the water flow test was conducted.

[0035] Figure 7 is a table showing the test conditions for the water flow test and the results of the transmission rate measurement of the test solution. Figure 8 is a table showing the results of the plaque count measurement of the test microorganisms. Figure 9 is a diagram showing the ultraviolet irradiation dose distribution of virtual particles. Figure 10 is a table showing the converted ultraviolet irradiation dose obtained after the water flow test and the converted ultraviolet irradiation dose obtained according to the CFD method.

[0036] [Determination of indicator bacteria] Among the microorganisms inhabiting raw drinking water, those belonging to the genus Methylobacterium are known to have high UV resistance. Therefore, five types of Methylobacterium microorganisms were prepared, and a resistance measurement test was conducted in which the microorganisms were irradiated with ultraviolet light to measure their UV resistance. Specifically, the UV resistance of Methylobacterium mesophilicum (NBRC15688 type), Methylobacterium komagatae (NBRC103627 type), Methylobacterium extorquens (NBRC15687 type), Methylobacterium fujisawaense (NBRC15843 type), and Methylobacterium radiotolerans (NBRC15690 type) was measured.

[0037] The UV resistance test was performed using the following procedure. First, the number of surviving microorganisms before UV irradiation was measured using the collimation method in accordance with Appendix B of ISO 20468-4. For this purpose, a test solution containing each of the five types of microorganisms was prepared, and the cells were cultured on standard agar medium using the pour plate method at 25°C for 14 days. After that, the number of colonies was measured, and the initial microbial concentration of each test solution was calculated.

[0038] Next, ultraviolet light was irradiated onto the test solution using an ultraviolet irradiation device 80 as shown in Figure 3. First, 5 mL of the test solution was placed in a glass watch glass 84 with a diameter of 10 cm. Then, the watch glass 84 containing the test solution was placed in a designated position in the clean bench, and ultraviolet light was irradiated onto the test solution for a predetermined time from a low-pressure, high-power amalgam lamp 81. Here, the average ultraviolet irradiance irradiated onto the test solution can be considered the same as the liquid surface irradiance. Therefore, the average amount of ultraviolet light was calculated by multiplying the measured value from the ultraviolet intensity meter by the irradiation time.

[0039] More specifically, an amalgam lamp 81 was installed inside a clean bench. Below the amalgam lamp 81, an upper light-shielding plate 82 and a lower inclined plate 83 were installed parallel to each other to prevent reflection of ultraviolet light. Circular holes H were formed in the upper light-shielding plate 82 and the lower inclined plate 83. Furthermore, a watch glass 84 was placed below the upper light-shielding plate 82 and the lower inclined plate 83, so that only the parallel ultraviolet light that passed through the upper light-shielding plate 82 and the lower inclined plate 83 was irradiated onto the test solution inside the watch glass 84. In addition, an automatic shutter 85 that can be opened and closed instantaneously was installed between the upper light-shielding plate 82 and the lower inclined plate 83.

[0040] The irradiation time of ultraviolet light was strictly controlled at predetermined intervals. Furthermore, the absorbance of ultraviolet light in the 254 nm wavelength range was measured for each test solution using a linear ultraviolet intensity meter (Shimadzu Corporation, model number "UV-1650PC"). When irradiating with ultraviolet light, the automatic shutter 85 was opened, and ultraviolet light was irradiated for a predetermined time. This resulted in the creation of multiple test solutions with different amounts of ultraviolet irradiation. After the ultraviolet irradiation trial, the survival concentration of microorganisms was calculated for each test solution based on the number of colonies, the volume of the test solution, and the dilution ratio. The survival rate of microorganisms in each test solution was also calculated from these results. Specifically, the survival rate was calculated by dividing the survival concentration N of microorganisms by the initial concentration N0 of the microorganisms.

[0041] As a result, as shown in Figure 2, we were able to obtain the survival rate in relation to the amount of UV irradiation for each microorganism. It was found that Methylobacterium radiotolerans had a similar or higher level of UV resistance compared to the other four types of bacteria. Therefore, Methylobacterium radiotolerans was selected as the indicator bacterium.

[0042] The survival rate of this indicator bacterium was as shown in the table in Figure 4. This resulted in a survival rate of 1.0 × 10⁻⁶. -6 To achieve this sterilization standard, the amount of ultraviolet radiation that should be irradiated onto the indicator bacteria is 128.0 mJ / cm². 2 It was found that... Furthermore, an approximate formula was obtained based on the inactivation curve of the indicator bacteria shown in Figure 2. Note that the survival rate was 1.0 × 10⁻⁶. -6 This sterilization threshold is the same as the sterilization threshold set by the US FDA (Food and Drug Administration), which is a survival rate of 1.0 x 10⁻¹⁰. -5 A safety factor of 10 -1 It is set by multiplying by .

[0043] [Sterilization capacity of sterilization device] Next, in order to determine the equivalent UV irradiation dose that indicates the sterilization capacity of the sterilization device 30, MS2, which exhibits UV resistance similar to that of microorganisms of the genus Methylobacterium, was used as the test microorganism, and its UV resistance was measured using the plaque assay method described below. The diluted test solution was poured onto the lower layer of culture medium formed in a Petri dish. Then, Escherichia coli, the host bacterium, was added to the upper layer of culture medium, gently mixed without creating bubbles, poured into the Petri dish, and the upper layer of culture medium and the test solution were mixed. After the upper layer of culture medium solidified, it was incubated in a constant temperature bath for a predetermined time. Furthermore, the number of plaques (colonies) ranging from 10 to 300 was measured on the Petri dish. The number of surviving plaques of MS2 was calculated from the number of plaques, the volume of the test solution, and the dilution ratio. As a result, the survival rate of the test microorganism was as shown in the table in Figure 5. An approximate formula was then obtained based on the inactivation curve of the test microorganism. The resistance measurement test was conducted using the same method as the measurement of UV resistance to the indicator bacteria described above, so a detailed explanation will be omitted.

[0044] Next, a water flow test was conducted to evaluate the sterilization capacity of the sterilization device 30. Specifically, the converted ultraviolet irradiation dose in the sterilization device 30 was determined according to the method described in Appendix B of ISO 20468-4. In the following explanation, the converted ultraviolet irradiation dose determined according to the said method is referred to as "RED real (mJ / cm 2 ) Furthermore, in the explanation of the water flow test, the parts that were omitted from the explanation were performed according to the method described in Appendix B of ISO 20468-4.

[0045] Furthermore, CFD-I analysis was performed to evaluate the sterilization capacity of the sterilization device 30. This CFD-I analysis refers to numerical and simulation analysis aimed at determining the amount of ultraviolet irradiation by adding the calculation of ultraviolet intensity to computational fluid dynamics (CFD) calculations. Specifically, the converted ultraviolet irradiation amount for the sterilization device 30 was determined according to the method described in Appendix C of ISO 20468-4. In the following explanation, the converted ultraviolet irradiation amount determined according to this method is referred to as "REDCFD (mJ / cm 2 ) Furthermore, in the explanation of CFD-I analysis, the parts that were omitted were performed according to the method described in Appendix C of ISO20468-4.

[0046] First, to conduct the water flow test, the test line shown in Figure 6 was prepared, and the test line was sterilized by circulating a sodium hypochlorite solution. Next, sodium thiosulfate was added and circulated to neutralize the sodium hypochlorite, and then the water was drained. In addition, the test microorganisms were added to tap water that had been filtered using a pre-filter and an activated carbon filter to prepare the test solution. After that, the ultraviolet lamp 32 was turned on, and the water flow test was started after the ultraviolet output had stabilized sufficiently. Specifically, the test solution was passed through the sterilization device 30, and the number of test microorganisms before and after ultraviolet irradiation was measured to calculate the survival rate of the test microorganisms.

[0047] The configuration of the sterilization device 30 during the water flow test was as follows. First, six low-voltage, high-output amalgam lamps (model number "CS1004N" manufactured by Chiyoda Kogyo Co., Ltd.) were used as ultraviolet lamps 32. Each ultraviolet lamp 32 was housed in a quartz sleeve that was sealed in water inside the chamber 31C. Three ballasts (model number "CZ221") manufactured by Chiyoda Kogyo Co., Ltd. were used to maintain a constant voltage supply to the ultraviolet lamps 32. Furthermore, an ultraviolet intensity meter (model number "CUVS-GFX5-SH") manufactured by Chiyoda Kogyo Co., Ltd. was used as an ultraviolet intensity meter 33.

[0048] Furthermore, the sterilization capacity of the sterilization device 30 was evaluated by reproducing the state in which the chamber 31C of the sterilization device 30 has deteriorated over time and reached the end of its product life, that is, the time when it needs to be replaced. Specifically, in order to reproduce the state in which internal reflection is reduced, an ultraviolet cut film (model number "SN50" manufactured by Nexfilm Co., Ltd.) was attached to the inner surface of the sterilization device 30.

[0049] The UV output of each UV lamp 32 used was 59.2W. Furthermore, all six UV lamps 32 were lit inside the chamber 31C, and the stable value of the UV intensity was measured. The total UV output of all UV lamps 32 was then calculated.

[0050] Furthermore, the ultraviolet output of the ultraviolet lamp 32 was calculated according to formula 1 below. The calculation was performed assuming a light emission length of 906 mm for the reference lamp and 921 mm for the ultraviolet lamp 32.

[0051] (Equation 1) UV output of UV lamp 32 (W) = UV intensity of UV lamp 32 (mW / cm²) 2 )÷ UV intensity of the reference lamp (mW / cm²) 2 ) × Emission length of UV lamp 32 (mm) ÷ Emission length of reference lamp (mm) × UV output of reference lamp (W)

[0052] Samples of the test solution after UV irradiation were taken between the sterilization device 30 and the processing tank 91 that processes the test solution. In addition, four different flow rate conditions were used (i.e., 33 m³ for the first test). 3 / h, 2nd time 37m 3 / h, 3rd time 42m 3 / h, and 4th time 47m 3 The flow rate of the test solution flowing from the test solution tank 92 was set to 0.8 / h and measured by the flow meter 20 as the flow rate in the water flow test. The test conditions for this water flow test and the measurement results of the permeability of the test solution are shown in Figure 7. In all water flow tests under different flow rate conditions, samples were taken after passing a volume of test solution four times the volume of the sterilization device 30 through the water.

[0053] As a result, the measurement results of the plaque count of the tested microorganisms are as shown in Figure 8. Furthermore, the RED of the sterilization device 30... real This is the first time (flow rate 33m 3 ( / h) is 201.5 mJ / cm² 2 And the second time (flow rate 37m 3 The value ( / h) is 189.7 mJ / cm². 2And, the third time (flow rate 42m 3 The value ( / h) is 175.7 mJ / cm³. 2 And this was the 4th time (flow rate 47m 3 The value ( / h) is 162.2 mJ / cm³. 2 That was the case.

[0054] Note RED real This was calculated using an approximation formula based on the MS2 inactivation curve obtained from the above measurements. That is, RED real This can be determined as the amount of ultraviolet light that the test microorganism is thought to have received when the ratio of the number of plaques of the test microorganism before passing through Chamber 31C (i.e., before the test) to the number of plaques of the test microorganism after passing through Chamber 31C (i.e., the sample) (i.e., survival rate) is applied to an approximate formula.

[0055] Furthermore, for CFD-I analysis, a 3D CAD model of the sterilization device 30 was created using "Ansys SpaceClaim 2022R1," a 3D CAD (Computer-Aided Design) modeling software from ANSYS. A mesh was also generated using the 3D CAD modeling software for CFD-I analysis. Finally, virtual particles were tracked under the same water flow conditions as the water flow test (i.e., UV transmittance, flow rate, and UV output conditions) using "Ansys Fluent 2022R1," a fluid simulation software from ANSYS.

[0056] Specifically, under the shape and water flow conditions of the sterilization device 30, the trajectory and residence time of virtual particles identical in shape, size, and specific gravity to the test microorganism (i.e., MS2) were tracked when they were passed through the device. Based on the obtained particle tracking data, a CFD-I analysis model was created. Then, using the "UV Irradiation Distribution Calculation Program ver. 8.01" manufactured by Chiyoda Kohan Co., Ltd., the amount of ultraviolet irradiation each virtual particle received as it flowed through the sterilization device 30 was calculated under each water flow condition. The amount of ultraviolet irradiation was calculated assuming an ultraviolet output of 59.2W per ultraviolet lamp 32.

[0057] For example, a flow rate of 47 m 3 As shown in the UV irradiation dose distribution diagram in Figure 9, corresponding to the water flow condition of / h, the amount of UV irradiation received by the virtual particles was calculated. The horizontal axis in Figure 9 represents the amount of UV irradiation received by the virtual particles (mJ / cm²). 2 The vertical axis on the left in Figure 9 corresponds to the bar graph and shows the relative frequency distribution (%). The vertical axis on the right in Figure 9 corresponds to the line graph and shows the cumulative relative frequency distribution (%).

[0058] Furthermore, based on the amount of ultraviolet radiation the virtual particles receive, RED CFD The following was calculated. CFD This was calculated using an approximation formula based on the inactivation curve of MS2 obtained by the above measurements. Specifically, the survival rate of the test microorganism corresponding to the virtual particle was calculated based on the amount of ultraviolet irradiation the virtual particle received as it passed through chamber 31C. Then, the amount of ultraviolet irradiation that the virtual particle was thought to have received when the calculated survival rate was applied to the approximation formula was RED CFD This was the request.

[0059] As a result, RED as shown in Figure 10 CFD This was calculated. That is, RED CFD The flow rate is 33m 3 Under a water flow condition of / h, the concentration was 197.9 mJ / cm³. 2 The flow rate is 37 m 3 Under a water flow condition of / h, the concentration is 184.3 mJ / cm³. 2 The flow rate is 42 m 3 Under a water flow condition of / h, the concentration is 166.2 mJ / cm². 2 The flow rate is 47 m 3 Under a water flow condition of / h, the concentration is 154.4 mJ / cm³. 2 That was the case.

[0060] RED shown in Figure 10 real And, RED CFD When comparing the two, the calculated RED under all water flow conditions CFD However, RED realThe following was confirmed. This confirmed that the CFD-I analysis model created is valid.

[0061] [CFD-I analysis] After confirming the effectiveness of CFD-I analysis, CFD-I analysis was performed to evaluate the bactericidal capacity of the sterilization device 30 against indicator bacteria (i.e., Methylobacterium radiotolerans). Specifically, based on the amount of ultraviolet irradiation received by a hypothetical particle identical in shape, size, and specific gravity to the indicator bacteria, RED CFD The following was calculated. CFD This was calculated using an approximation formula based on the inactivation curve of the indicator bacteria obtained by the above measurements. Specifically, the survival rate of the indicator bacteria corresponding to the virtual particles was calculated based on the amount of ultraviolet irradiation received by the virtual particles as they passed through chamber 31C. Then, the amount of ultraviolet irradiation that the virtual particles were thought to have received when the calculated survival rate was applied to the approximation formula was calculated as RED CFD This was the request.

[0062] Furthermore, the conditions for this CFD-I analysis were as follows: the flow rate was 35 m³. 3 The parameters were as follows: 6 UV lamps 32, 59W UV output per UV lamp, 80% UV intensity maintenance rate, and 95% UV transmission maintenance rate for the quartz sleeve. Furthermore, considering the effect of water temperature, the ratio of the minimum value to the maximum value of the fluctuating UV intensity was set to 94.5% in the range of 10°C to 30°C.

[0063] As a result, CFD-I analysis revealed that RED CFD As 133.5 mJ / cm² 2 The following was obtained. As mentioned above, the survival rate of the indicator bacteria was 1.0 × 10⁻⁶. -6 The amount of ultraviolet radiation that should be irradiated to achieve this is 128.0 mJ / cm². 2 Therefore, RED CFD 133.5 mJ / cm² 2 According to the sterilization device 30, the survival rate of indicator bacteria is 1.0 × 10 -6It was found that this could be achieved. Furthermore, the RED required here CFD This value was obtained considering the state in which the chamber 31C has reached the end of its product life. On the other hand, when the sterilization device 30 is in a state that meets the design conditions, i.e., immediately after manufacture, the sterilization device 30 has the highest sterilization capacity.

[0064] [Effects on mineral content] The effects of ultraviolet irradiation on mineral components will be explained with reference to Figures 11 to 13. Figure 11 is an explanatory diagram illustrating the irradiation test apparatus 200. Figure 12A shows a target ultraviolet irradiation dose of 400 mJ / cm². 2 This table shows the sample preparation results for the following case. Figure 12B shows the results for when the target UV irradiation dose is 4000 mJ / cm². 2 This table shows the results of sample preparation 2 in the case of [the specified condition]. Figure 13 is a table showing the results of the analysis of the mineral components of the sample.

[0065] First, to investigate the effect of ultraviolet (UV) irradiation on mineral content, samples of drinking water were prepared by irradiating them with UV light. Specifically, using the irradiation test apparatus 200 shown in Figure 11, UV light was irradiated onto drinking water samples that would be used for mineral content analysis. Seven types of drinking water were tested, from Drinking Water A to Drinking Water G. For each type of drinking water, both unirradiated and UV-irradiated samples were prepared.

[0066] The irradiation test apparatus 200 includes an irradiation tank 201 for storing drinking water and a stirring blade 202 for stirring the drinking water in the irradiation tank 201. The irradiation test apparatus 200 also includes a motor 203 for rotating the stirring blade 202 and a lamp 204 installed in the irradiation tank 201 for irradiating ultraviolet light. This lamp 204 is housed in a quartz sleeve 205 installed so as to penetrate the irradiation tank 201. An aluminum shutter 206 is also placed inside the sleeve 205 to shield the ultraviolet light from the lamp 204. This aluminum shutter 206 can be removed in the direction indicated by arrow 200A. The irradiation test apparatus 200 also includes a thermometer 207 for measuring the temperature of the drinking water in the irradiation tank 201.

[0067] In the irradiation tests for each type of drinking water, 2 liters of drinking water were placed in the irradiation tank 201. Then, with the ultraviolet light shielded by the aluminum shutter 206, the lamp 204 was turned on. After the lamp was left on for a predetermined time with the ultraviolet light shielded to stabilize, the aluminum shutter 206 was removed. From this point, ultraviolet irradiation was started and continued for a predetermined time until the target amount of ultraviolet light was delivered to the drinking water.

[0068] Furthermore, while the ultraviolet light was being irradiated, the drinking water was stirred by the stirring blade 202. Specifically, the motor 203 was rotated to a rotation speed of 700 rpm. This stirring ensured that all of the drinking water in the irradiation tank 201 was uniformly irradiated with ultraviolet light. In other words, it can be assumed that all of the drinking water in the irradiation tank 201 received approximately the same amount of ultraviolet light. The amount of ultraviolet light irradiated was calculated according to formula 2 below. The average ultraviolet light intensity in the irradiation tank 201 was calculated using a known method.

[0069] (Equation 2) UV irradiation amount (mJ / cm 2 ) = Average ultraviolet intensity in irradiation chamber 201 (mW / cm²) 2 ) x irradiation time (s)

[0070] Here, the target ultraviolet radiation dose to irradiate drinking water is 400 mJ / cm².2 The target ultraviolet irradiation dose was set considering the state in which the sterilization device 30 meets the design conditions for having the highest sterilization capacity. Specifically, assuming that the maintenance rate of the ultraviolet intensity of the ultraviolet lamp 32 decreases from 100% of the design conditions to 80% when the product reaches the end of its lifespan, a maintenance rate of 0.8 was set. In addition, assuming that the ultraviolet intensity of the ultraviolet lamp 32 is higher than the design conditions, an intensity safety factor of 1.2 was set.

[0071] Furthermore, assuming that the contribution of ultraviolet reflection from the inner surface of chamber 31C under the design conditions is 1.6 times that of the product at the end of its lifespan, a reflectance ratio of 1.6 was set. In addition, assuming that the ultraviolet reflectance due to the material of chamber 31C is higher than the design conditions, a semi-safety factor of 1.2 was set. The ultraviolet irradiation dose under conditions that satisfy the design conditions (hereinafter also referred to as the "design ultraviolet irradiation dose") was calculated according to the following formula 3.

[0072] (Equation 3) Designed ultraviolet irradiation amount 384.48 (mJ / cm 2 ) = RED (Red) - product has reached the end of its lifespan. CFD 133.5 (mJ / cm²) 2 ) ÷ Maintenance rate 0.8 x Intensity safety factor 1.2 x Reflectance ratio 1.6 x Reflection semi-safety factor 1.2

[0073] The target UV radiation dose to be irradiated onto drinking water is the design UV radiation dose of 384.48 mJ / cm². 2 To ensure it does not fall below 400 mJ / cm² 2 This was done. As a result, we were able to obtain the sample results shown in Figure 12A. The specific ultraviolet irradiation dose for sample A2 was 403.3 mJ / cm². 2 Therefore, sample B2 was 407.6 mJ / cm³. 2 Therefore, sample C2 was 410.9 mJ / cm³. 2 Therefore, sample D2 was 400.8 mJ / cm³. 2 Therefore, sample E2 was 401.5 mJ / cm³. 2 Therefore, sample F2 was 411.3 mJ / cm². 2 That was the case.

[0074] Furthermore, considering the possibility that drinking water, which normally passes through the sterilization device 30 in about 9 seconds, may take 10 times longer (i.e., 90 seconds) to pass through the sterilization device 30, the maximum target ultraviolet irradiation dose is set at 4000 mJ / cm², which is 10 times the normal amount. 2 The settings were configured. Then, by irradiating with ultraviolet light in the same manner as the irradiation test described above, the sample results shown in Figure 12B were obtained. The specific ultraviolet irradiation dose for sample E4 was 4042.0 mJ / cm². 2 The results were as follows. Note that samples E1, E2, E3, and E4 in Figure 12A are the same type of drinking water, except for the amount of UV irradiation. Furthermore, samples E1 through E4 have higher total hardness before UV irradiation than the other types of drinking water. Therefore, samples E1 through E4 were selected as representative drinking water for testing the effect on mineral content.

[0075] The prepared samples were then analyzed by the Japan Food Research Laboratories. The results are shown in Figure 13. The analytes included total hardness, pH, free carbon dioxide, total alkalinity, and silicic acid content (SiO2). Total hardness was determined by ion chromatography, and calculated by summing the measured values ​​of calcium and magnesium. pH was determined by the glass electrode method. Free carbon dioxide was determined by titration, with a limit of quantification of 5.0 mg / L. Total alkalinity was determined by titration, using a strong acid titration with a pH of 4.8 as the endpoint, and the amount of acid was calculated as the amount of CaCO3. Silicic acid content was determined by ICP emission spectrometry.

[0076] As shown in Figure 13, for example, when comparing sample A1, which was not irradiated with UV light, with sample A2, which was irradiated with UV light, only the total alkalinity decreased by 1 mg / L after UV irradiation. Furthermore, other mineral components remained unchanged. Thus, it was found that the mineral components in drinking water after UV irradiation did not decrease, or were not substantially decreased. This resulted in a concentration of 400 mJ / cm³. 2 For example, the degree is 400.8 mJ / cm². 2It has been found that even when irradiated with ultraviolet rays, it does not affect the mineral components.

[0077] This is the same for sample E4 irradiated with ultraviolet rays of 4042.0 mJ / cm 2 That is, it has been found that even when irradiated with ultraviolet rays at the maximum target ultraviolet ray irradiation amount, the mineral components contained in the drinking water after ultraviolet ray irradiation have not decreased or have not substantially decreased. Thereby, even when irradiated with ultraviolet rays of about 4000 mJ / cm 2 As an example, even when irradiated with ultraviolet rays of 4042.0 mJ / cm 2 it has been found that it does not affect the mineral components.

[0078] According to the sterilization system 101 described above, drinking water can be sterilized by irradiating ultraviolet rays without affecting the mineral components. Thereby, it is possible to reduce the emission amount of greenhouse gases and to achieve sterilization of drinking water that does not affect the mineral components. Further, by setting the equivalent ultraviolet ray irradiation amount of the ultraviolet rays irradiated to the drinking water to 128.0 mJ / cm2 or more, even if there is variation in the residence time of microorganisms in the sterilization device 30 compared to the integrated irradiation amount, the desired sterilization achievement standard can be more surely achieved.

[0079] Although the present invention has been described above with reference to each embodiment, the present invention is not limited to the above embodiments. Inventions modified within the scope not contrary to the present invention and inventions equivalent to the present invention are also included in the present invention. Further, each embodiment, each modified form, and the technical means included in each embodiment or each modified form can be appropriately combined within the scope not contrary to the present invention.

[0080] For example, in order to obtain a desired equivalent ultraviolet ray irradiation amount, the number of ultraviolet lamps 32 arranged in the sterilization device 30 may be increased or decreased. When increasing or decreasing the addition of the ultraviolet lamp 32, the equivalent ultraviolet ray irradiation amount can be calculated by performing CFD-I analysis again. Further, the manufacturing system 100 may manufacture a beverage made of sterilized drinking water, or may manufacture a beverage containing sterilized drinking water as a raw material.

[0081] Some or all of the above embodiments may also be described as follows, but are not limited to the following:

[0082] (Note 1) A sterilization system for sterilizing drinking water, such as natural water, natural mineral water, or mineral water, in a manner that does not affect the mineral components contained in the drinking water, The sterilization apparatus comprises a chamber through which the drinking water flows, and an irradiation device that irradiates the drinking water flowing in the chamber with ultraviolet light. The equivalent ultraviolet radiation dose of the ultraviolet light irradiated onto the drinking water in the chamber is 128.0 mJ / cm². 2 That concludes the explanation of the sterilization system.

[0083] (Note 2) The aforementioned converted ultraviolet irradiation dose is 133.5 mJ / cm². 2 The sterilization system described in Appendix 1 is as described above.

[0084] (Note 3) The aforementioned converted ultraviolet irradiation dose is 4042.0 mJ / cm². 2 The sterilization system described in Appendix 1 or 2 below.

[0085] (Note 4) The aforementioned converted ultraviolet irradiation dose is 400.8 mJ / cm². 2 The sterilization system described in any one of the following appendices 1 to 3.

[0086] (Note 5) A sterilization system according to any one of the appendices 1 to 4, comprising a filter through which the drinking water passes, having a pore size of 0.1 μm or more and 0.22 μm or less.

[0087] (Note 6) The converted UV irradiation dose is the UV irradiation dose in the sterilization device, and is determined according to the method described in Appendix B of ISO20468-4, and is the sterilization system according to any one of Supplementary Notes 1 to 5.

[0088] (Supplementary Note 7) The converted UV irradiation dose is the UV irradiation dose in the sterilization device, and is determined according to the method described in Appendix C of ISO20468-4, and is the sterilization system according to any one of Supplementary Notes 1 to 5.

[0089] (Supplementary Note 8) A beverage manufacturing method for sterilizing drinking water, which is natural water, natural mineral water, or mineral water, so as not to affect the mineral components contained in the drinking water to produce a beverage, Flowing the drinking water into the chamber, Irradiating the drinking water flowing in the chamber with ultraviolet rays by an irradiator, The converted UV irradiation dose of the ultraviolet rays irradiated on the drinking water in the chamber is 128.0 mJ / cm 2 or more, and is a beverage manufacturing method.

Explanation of Signs

[0090] 30: Sterilization device 31C: Chamber 40: Filter 101: Sterilization system

Claims

1. A sterilization system for sterilizing drinking water, such as natural water, natural mineral water, or mineral water, in a manner that does not affect the mineral components contained in the drinking water, The sterilization apparatus comprises a chamber through which the drinking water flows, and an irradiation device that irradiates the drinking water flowing in the chamber with ultraviolet light. The equivalent ultraviolet radiation dose irradiated onto the drinking water in the chamber is 128.0 mJ / cm². ２ That concludes the explanation of the sterilization system.

2. The aforementioned converted ultraviolet irradiation dose is 133.5 mJ / cm². ２ The sterilization system according to claim 1 is as described above.

3. The aforementioned converted ultraviolet irradiation dose is 4042.0 mJ / cm². ２ The sterilization system according to claim 1, which is as follows:

4. The aforementioned converted ultraviolet irradiation dose is 400.8 mJ / cm². ２ The sterilization system according to claim 1, which is as follows:

5. The sterilization system according to claim 1, comprising a filter through which the drinking water passes, having a pore size of 0.1 μm or more and 0.22 μm or less.

6. The sterilization system according to any one of claims 1 to 5, wherein the converted ultraviolet irradiation dose is determined as the ultraviolet irradiation dose in the sterilization device in accordance with the method described in Appendix B of ISO 20468-4.

7. The sterilization system according to any one of claims 1 to 5, wherein the converted ultraviolet irradiation dose is determined as the ultraviolet irradiation dose in the sterilization device in accordance with the method described in Appendix C of ISO 20468-4.

8. A method for producing a beverage by sterilizing drinking water in a manner that does not affect the mineral components contained in drinking water that is natural water, natural mineral water, or mineral water, The drinking water is poured into the chamber. The drinking water flowing through the chamber is irradiated with ultraviolet light by an irradiation device. The equivalent ultraviolet radiation dose irradiated onto the drinking water in the chamber is 128.0 mJ / cm². ２ The above is the method for manufacturing a beverage.

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