JP2000140073A - Method and device for sterilization - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively sterilize food, medical devices, liquid oxygen, serum or the like by producing simply high pressure without a large scale high pressure generator. SOLUTION: After an object to be sterilized and a liquid surrounding the object are airtightly contained in a flexible container 16, a liquid to be sterilized is airtightly contained in the flexible container 16, and the container is stored in a pressure container body 10, a freezing medium 18 is filled into the pressure container body, a liquid inlet 12 is closed with an airtight plug 14, the freezing medium inside is frozen by cooling the pressure container, and high pressure due to the freezing of the freezing body is produced in the pressure container.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sterilization method for killing various microorganisms such as bacteria and fungi, in particular, a simple sterilization method utilizing high pressure and low temperature, and a sterilization apparatus used for carrying out the method. About.

[0002]

2. Description of the Related Art As a physical sterilization method for various microorganisms, there are methods generally used widely such as heating, freezing, and ultraviolet irradiation, and a method of killing microorganisms by placing them in a high-pressure atmosphere. Since the sterilization method can sterilize without deterioration or denaturation of the material to be sterilized,
In recent years, it has been mainly studied as a food sterilization method and has been partially used. Further, in order to enhance the sterilization effect, a sterilization method in which high-pressure treatment is performed at a low temperature has been studied.

[0003] In the above-mentioned high-pressure sterilization, a high pressure of, for example, about 100 MPa or more is required in order to effectively kill microorganisms. Conventionally, a high pressure is generated using a hydraulic pump or the like.

[0004]

However, in the conventional high-pressure sterilization method, a large-scale high-pressure generator is required to generate high pressure, and a large amount of equipment is required in comparison with other conventional sterilization methods. There is a problem that costs are required. In order to further enhance the sterilizing effect, it is necessary to treat the microorganisms at a higher pressure, and an increase in the cost of the apparatus is required to improve the sterilizing effect.

The present invention has been made in view of the above circumstances, and can easily generate high pressure without the need for a large-scale high-pressure generating device, and can be used for other than foods such as foods and medical tools. It is an object of the present invention to provide a sterilization method capable of sterilizing biological fluids such as articles, enzyme solutions, and serum, and liquid pharmaceuticals, and a sterilization apparatus capable of suitably performing the method.

[0006]

The invention according to claim 1 is
The object to be sterilized is housed in a pressure-resistant container, and the pressure-resistant container is filled with a freezing medium in a liquid state to eliminate gas, and the object to be sterilized and the freezing medium are sealed in the pressure-resistant container. Is cooled to freeze all or part of the internal freezing medium for sterilization.

The invention according to a second aspect of the present invention is characterized in that after the liquid to be sterilized is sealed in the pressure-resistant container in a state where the liquid to be sterilized is filled in the pressure-resistant container and gas is removed, the pressure-resistant container is cooled and the internal pressure is reduced. It is characterized in that all or a part of the sterilizing solution is sterilized by freezing.

According to a third aspect of the present invention, a filling liquid for filling an object to be sterilized and its surroundings and a freezing medium in a liquid state are separated from each other by a deformable separating member, and
After filling the inside of the pressure vessel with the gas removed and sealing the sterilization object and the filling liquid and the freezing medium in the pressure vessel, the pressure vessel is cooled to freeze all or part of the freezing medium inside. It is characterized in that it is sterilized by being caused.

According to a fourth aspect of the present invention, in the sterilization method according to the third aspect, the object to be sterilized is housed in a deformable plastic container or bag, and the container or bag is filled with a filling liquid and gaseous. In a state in which the object to be sterilized and the filling liquid are sealed in a container or a bag in a state in which the liquid medium is filled with a freezing medium in a liquid state, the gas is eliminated in the pressure-resistant container. In this state, the object to be sterilized, the filling liquid, and the freezing medium are sealed in the pressure vessel.

According to a fifth aspect of the present invention, the object to be sterilized and the freezing medium in a liquid state are separated from each other by a deformable isolating member, and filled in the pressure-resistant container to eliminate the gas, so that the pressure-resistant container is filled. After the liquid to be sterilized and the freezing medium are sealed therein, the pressure-resistant container is cooled to sterilize the whole or a part of the freezing medium inside by freezing.

According to a sixth aspect of the present invention, there is provided the sterilization method according to the fifth aspect, wherein the liquid to be sterilized is filled in a deformable plastic container or bag to remove gas from the container or bag. After the sterilized liquid is sealed in the pressure container, the liquid container is filled with a freezing medium in a liquid state and the gas is eliminated, and the liquid to be sterilized and the freezing medium are sealed in the pressure container. It is characterized by doing.

According to a seventh aspect of the present invention, there is provided the sterilization method according to the first aspect or the third to sixth aspects, wherein the salt which expands by freezing and eutectic formation when cooled is used as a freezing medium. It is characterized by using a solution.

[0013] The invention according to claim 8 is a pressure-resistant container main body in which a liquid can be accommodated therein and in which a liquid inlet is formed, and the liquid inlet of the pressure-resistant container main body is connected to the internal pressure of the pressure-resistant container main body. A sterilization device is characterized by comprising a hermetic plug that is liquid-tightly closed even when ascending.

According to a ninth aspect of the present invention, the inside is partitioned into two chambers by a diaphragm, and one of the chambers is sealed so that the inside thereof is filled with a freezing medium, and the liquid can be stored inside the other chamber. A pressure-resistant container body having a liquid inlet formed in the other chamber side and a hermetic plug that closes the liquid inlet of the pressure-resistant container body in a liquid-tight manner even when the internal pressure of the pressure-resistant container body increases. The apparatus is characterized in that the apparatus is configured.

In the sterilization method according to the first aspect of the present invention, a freezing medium, for example, water filled and sealed in a pressure-resistant container is cooled to a temperature below the freezing point and frozen.
Further, in the sterilization method according to the second aspect of the present invention, the liquid to be sterilized, for example, an enzyme liquid, which is filled and sealed in the pressure-resistant container, is cooled to a temperature below the freezing point and frozen, thereby expanding in volume. However, the freezing medium or the liquid to be sterilized is sealed in the pressure-resistant container, and the inner wall surface of the pressure-resistant container suppresses the volume expansion of the entire contents, and accordingly, a high pressure is generated inside the pressure-resistant container. Due to the bactericidal action by the high pressure and the bactericidal action by freezing, microorganisms such as bacteria and molds attached to the object to be sterilized or present in the liquid to be sterilized are killed.

[0016] In the sterilization method according to the third aspect of the present invention, the filling medium and the freezing medium filled in the pressure-resistant container and sealed and separated from each other by the deformable separating member are selected from the group consisting of:
In the sterilization method according to the fifth aspect of the present invention, the freezing medium, for example, water, is filled in a pressure-resistant container, and the sterilized liquid, for example, an enzyme liquid and the freezing medium, are separated from each other by a deformable separating member. Among them, the freezing medium, for example, water, is cooled to a temperature below the freezing point and freezes to expand its volume, but the freezing medium and the filling liquid or the liquid to be sterilized are sealed in a pressure-resistant container, and the pressure-resistant container Due to the inner wall surface of the container, volume expansion of the whole contents is suppressed, and accordingly, a high pressure is generated inside the pressure-resistant container, and the high pressure is applied to the filling liquid or the liquid to be sterilized separated by the freezing medium and the separating member. Due to the bactericidal action by the high pressure and the bactericidal action by the low temperature, microorganisms such as bacteria and molds that adhere to the substance to be sterilized in the filling liquid or are present in the liquid to be sterilized are killed.

In the sterilization method according to each of the fourth and sixth aspects of the present invention, the freezing medium filled in the pressure-resistant container and sealed is cooled to a temperature below the freezing point and frozen to expand its volume. The inner wall surface of the pressure-resistant container suppresses volume expansion of the entire contents, and the high pressure generated inside the pressure-resistant container is filled and sealed in a plastic container or bag, and the liquid to be sterilized is sterilized. , Sterilization of the material to be sterilized or the liquid to be sterilized in the filling liquid is performed.

In the sterilization method according to the present invention, since the volume expansion when the freezing medium is cooled and frozen is larger than the volume expansion when the water is cooled and frozen, the inside of the pressure vessel is higher. Pressure develops.

In order to use the sterilization apparatus of the present invention, an object to be sterilized is housed in a pressure-resistant container body, and a freezing medium, for example, water is injected into the pressure-resistant container body through a liquid inlet. With the container body filled with water and gas removed, the liquid injection port is closed in a liquid-tight manner with a hermetic stopper, and the substance to be sterilized and water are sealed inside the pressure-resistant container body, or inside the pressure-resistant container body. A liquid to be sterilized, for example, an enzyme solution, is injected through the liquid inlet, and the enzyme liquid is filled in the pressure-resistant container body to eliminate gas. Seal the enzyme solution. Alternatively, in a pressure-resistant container main body, a plastic container or bag in which a substance to be sterilized and a filling liquid filling the periphery thereof are sealed is housed,
Alternatively, a sterile liquid, for example, a plastic container or bag sealed with an enzyme solution is housed, and a freezing medium, for example, water is injected through a liquid inlet into the pressure-resistant container body, and the pressure-resistant container body is filled with water. With the gas removed, the liquid inlet is closed in a liquid-tight manner with a hermetic plug, and the object to be sterilized and the filling liquid or enzyme solution and water are sealed in the pressure-resistant container body. Thereafter, by cooling the pressure vessel main body and freezing the water inside at a temperature below the freezing point, as described above,
A high pressure is generated inside the pressure-resistant container body, and due to the sterilizing action by the high pressure and the sterilizing action by freezing or the low temperature, the microorganisms such as bacteria and fungi that adhere to the object to be sterilized or exist in the enzyme solution are removed. To die.

In order to use the sterilization apparatus according to the ninth aspect of the present invention, an object to be sterilized is accommodated in the other chamber of the pressure vessel main body,
Inject the antifreeze liquid into the other room through the liquid inlet, fill the other room with the antifreeze liquid and eliminate the gas. Seal the object and the antifreeze liquid, or the liquid to be sterilized through the liquid inlet into the other chamber of the pressure-resistant container body,
For example, in a state where an enzyme solution is injected and the other chamber is filled with the enzyme solution to remove gas, the liquid inlet is closed in a liquid-tight manner with a hermetic stopper, and the enzyme solution is sealed in the other chamber. Thereafter, the pressure vessel main body is cooled, and a freezing medium sealed in one chamber, for example, water is frozen at a temperature below the freezing point. As described above, a high pressure is generated inside the pressure vessel main body. Microorganisms such as bacteria and fungi that adhere to the object to be sterilized or are present in the enzyme solution are killed by the sterilizing action of high pressure and the sterilizing action of low temperature.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a schematic vertical sectional view showing an example of the structure of a sterilizing apparatus used for carrying out the sterilizing method according to the present invention. The sterilization apparatus includes a pressure-resistant container body 10 capable of storing a liquid therein and having a liquid inlet 12 formed therein,
And a hermetic plug 14 for closing the liquid inlet 12 of the pressure-resistant container body 10. The pressure-resistant container main body 10 has a structure that can withstand a high pressure of, for example, 100 to 200 MPa or more, and is formed of, for example, a thick wall made of stainless steel. The internal pressure of the pressure-resistant container body 10 is 100
Even if the pressure rises to 200 MPa or more, the liquid inlet 12 of the pressure-resistant container body 10 can be closed in a liquid-tight manner so that the liquid sealed inside does not leak.

When an object to be sterilized, such as a medical device, is to be sterilized, the medical device is first stored in a deformable plastic container 16 (or bag).
The inside of the container 6 is filled with a filling liquid, for example, water, ethanol, etc., to eliminate air, and the medical device and the filling liquid are sealed in the container 16. When a sterilizing solution, for example, an enzyme solution is to be sterilized, the enzyme solution is placed in a plastic container 16.
(Or bag) is filled to eliminate air, and the enzyme solution is sealed in the container 16. Then, after the container 16 is accommodated in the pressure-resistant container main body 10, a freezing medium 18 in a liquid state is injected into the pressure-resistant container main body 10 through the liquid injection port 12, and the freezing medium 18 is filled in the pressure-resistant container main body 10 to remove air. In this state, the liquid inlet 12 is closed by the hermetic stopper 14, and the medical device sealed in the container 16, the filling liquid or the enzyme solution, and the freezing medium 18 are sealed in the pressure-resistant container main body 10. As the freezing medium, water or an aqueous solution of a salt such as magnesium sulfate or potassium sulfate is used. The condition of the freezing medium is that it is liquid at room temperature, is easy to handle, solidifies at an appropriate temperature, for example, a temperature of about 0 to −20 ° C., and expands in volume at the time of solidification. The larger the value, the better.

A sterilization apparatus comprising a pressure-resistant container body 10 containing a medical tool and a container 16 containing a filling liquid or an enzyme solution and sealing a freezing medium 18 and a hermetic plug 14 is put into a freezer and cooled. When the temperature of the freezing medium 18 falls below the freezing point (or below the freezing point when the freezing medium 18 is water) when the sterilizing device is cooled, the freezing medium 18 starts to solidify and freezes as the temperature of the freezing medium 18 decreases. Medium 1
8, the freezing medium 18 partially expands in volume with the freezing. However, since the freezing medium 18 is sealed in a state where the inside of the pressure-resistant container body 10 is filled, the volume expansion of the entire contents is suppressed by the inner wall surface of the pressure-resistant container body 10, and accordingly, the pressure-resistant container body 10 High pressure is generated inside. Then, the high pressure generated by freezing of the freezing medium 18 is applied to the filling liquid or the enzyme solution sealed in the plastic container 16, and adheres to the medical device by a sterilizing action by the high pressure and a sterilizing action by the low temperature (or). Microorganisms such as bacteria (in the enzyme solution) are killed.

In the above-mentioned sterilization treatment, the object to be sterilized is accommodated in a plastic container 16, the container 16 is filled with a filling liquid and sealed, and the liquid to be sterilized is placed in the plastic container 16. Filled and sealed, the container 16
Is housed in the pressure-resistant container body 10, and the pressure-resistant container 10 is filled with a freezing medium 18 and hermetically sealed to cool the sterilizing apparatus.
The inside of the pressure-resistant container body 10 is filled with a freezing medium and sealed, and the liquid to be sterilized is directly injected into the pressure-resistant container body 10 and filled and sealed. It may be. At this time, the microorganisms can be killed by the sterilizing action by high pressure and the sterilizing action by freezing. When the object to be sterilized is stored in the pressure-resistant container body 10 as it is, filled with a freezing medium and sealed to cool the sterilizing apparatus, when an aqueous solution of a salt is used as the freezing medium, the freezing medium becomes sherbet-shaped. This is preferable because the object to be sterilized can be easily removed from the freezing medium after the sterilization treatment. In addition, when disinfecting articles that cause inconvenience when in contact with a filling liquid, for example, ethanol, or when disinfecting food such as meat, vacuum-package those articles and foods, and sterilize them. May be stored in the plastic container 16 or may be stored in the pressure-resistant container body 10 as it is.

FIG. 2 is a schematic longitudinal sectional view showing another example of the configuration of the sterilizing apparatus. In this sterilizing apparatus, the inside of a pressure-resistant container body 20 formed of a thick wall of stainless steel or the like and having a pressure-resistant structure is formed of two chambers by a deformable diaphragm (partition plate or membrane) 22, that is, a freezing chamber 24 and a sterilizing chamber 26. And is divided into. The freezing chamber 24 is sealed and the inside thereof is always filled with a freezing medium 28. A liquid injection port 30 is formed on the sterilization chamber 26 side, and the liquid injection port 30 is liquid-tightly closed by a hermetic plug 32 so that the liquid sealed inside does not leak even when the internal pressure increases. I have.

When an object to be sterilized, for example, a medical device is to be sterilized using the sterilizing apparatus shown in FIG.
The medical device 34 is accommodated in the sterilization room 26 and the sterilization room 26
The inside is filled with a filling liquid 36 such as water or ethanol to eliminate air, and in this state, the liquid inlet 30 is
Is closed, and the medical device 34 and the filling liquid 36 are sealed in the sterilization chamber 26. When a sterilizing solution, for example, an enzyme solution, is to be sterilized, the enzyme solution is injected into the sterilizing chamber 26 to fill the same, and the liquid injection port 30 is closed by the hermetic plug 32 while the air is removed. Then, the enzyme solution is sealed in the sterilization chamber 26. Then, the sterilizer is cooled in the freezer. The sterilizer is cooled and the freezing medium 2 in the freezing chamber 24 is
When the temperature of the freezing medium 8 falls below the freezing point, the freezing medium 28 starts to solidify, and the freezing medium 28 freezes as the temperature of the freezing medium 28 decreases, and the freezing medium 28 expands in volume with the freezing. However, the freezing medium 28 is provided in the pressure vessel main body 20.
Is sealed in a state where it is filled in the freezing chamber 24, and the sterilizing chamber 26 is filled.
The inside is sealed with a filling liquid 36 (or an enzyme solution) filled therein, so that the inner wall surface of the pressure-resistant container body 20 suppresses volume expansion of the entire contents, and accordingly, the inside of the pressure-resistant container body 20 High pressure is generated in Then, the high pressure generated by the freezing of the freezing medium 28 is applied to the filling liquid 36 (or the enzyme liquid) sealed in the sterilization chamber 26,
Due to the sterilizing action by the high pressure and the sterilizing action by the low temperature, microorganisms such as bacteria attached to the medical device 34 (or present in the enzyme solution) are killed.

[0028]

EXAMPLES Hereinafter, more specific examples of the present invention will be described with reference to experimental examples and the results thereof.

[Experimental method] [1. Preparation of Experimental Material] Zygosaccharomyces yeast for salt-resistant miso
ces rouxii) cultivating IAM 12880 in 5% salted wort medium at a temperature of 30 ° C. for 5 days,
After washing the cells with sterile water, suspend the cells in sterile water,
0.3 ml of the suspension was sealed in a plastic bag to obtain a sample a under pressure. Non-salt-tolerant yeast Saccharomyces cerevisiae
siae) IAM 4274 in wort medium
Lactobacillus lactobacillus brevis (Lactobacil)
lrus brevis) GYP IFO 12005
In the medium, Escherichia coli (Esch)
erichia coli) IFO 3972 was cultured in Mueller-Hinton medium at a temperature of 30 ° C. for 2 days each, and the cells were washed with sterile water.
Each of the cells was suspended in sterilized water.
3 ml was sealed in a plastic bag to obtain samples b, c and d to be pressurized. Also, Aspergillus oryzae H
-3 and Aspergillus niger
rus niger) IFO 9455, respectively
The cells were cultured on a potato dextrose agar at a temperature of 30 ° C. for 7 days, each spore generated was suspended in sterilized water, 0.3 ml of each suspension was sealed in a plastic bag, and each sample under pressure e, f.

[2. High pressure generation method)
A stainless steel pressure vessel having a structure as shown in FIG. 3 (commercial international company, pressure resistance 300 atm, internal filling capacity 20 ml, L1 = 283 mm, L2 =
241 mm, L3 = 174 mm, D = 38.1 mm), the pressurized containers a to f are respectively accommodated in the pressure-resistant container, and the pressure-resistant container is filled with distilled water while the distilled water overflows from the pressure-resistant container. The sample to be pressurized and distilled water were sealed in a pressure vessel. The pressure vessel was placed in a freezer set at various temperatures and cooled for 24 hours.
As a device for externally applying pressure for a comparative test, a pressurization test device for food (MFP) manufactured by Mitsubishi Heavy Industries, Ltd.
-7000) was used.

[3. Method for Measuring Pressure Generated Inside Pressure-Resistant Vessel] As shown in a vertical sectional view in FIG. 4, a pressure gauge (Nagano Keiki Co., Ltd., diaphragm type, Type KH78 type)
66 connected to a pressure-resistant container (manufactured by Optical High Pressure Co., Ltd., content 1
67 ml), a rubber balloon (sealed with air and sealed with a cotton thread) 70 containing water is housed in 68, the surrounding area is filled with ethanol (antifreeze liquid, pressure transmission medium) 72, and ethanol is poured from the upper opening. A rubber balloon 70 sealed with water by closing the upper opening with a stopper 74 while overflowing.
And ethanol 72 was sealed in pressure vessel 68. At this time, the air in the tube 76 connected to the pressure gauge 66 and the air in the pressure vessel 68 were completely expelled and replaced with ethanol 72. Then, the pressure-resistant container 68 is immersed in a refrigerant (ethanol and water) 80 stored in a constant temperature bath 78 set at a predetermined temperature to cool the pressure-resistant container 68.
The pressure generated inside was measured.

[4. Measuring method of the number of bacteria] Yeast Sago Saccharomyces luxii for salt-resistant miso IAM 12880
5% salted malt agar medium, and malt agar medium for the non-salt-tolerant yeast Saccharomyces cerevisiae IAM 4274. Aspergillus oryzae H-3
For 9455, a lactic acid bacterium Lactobacillus brevis IF was used using a potato dextrose agar medium.
For O12005, Escherichia coli Escherichia coli IFO 3 was used using a BCP plate count agar.
For 972, the number of bacteria is measured by a dilution plate culture method using a Mueller-Hinton agar medium.

[Experimental results] [1. Generation of High Pressure Inside Pressure-Resistant Vessel] Using the apparatus shown in FIG. 4, a pressure-resistant container 68 in which 140 ml of water is sealed in a rubber balloon 70 (the amount of ethanol in the pressure-resistant container 68 is 27 ml) is placed at −22 ° C. When immersed in the refrigerant 80 in the thermostat 78 set at the temperature, the pressure rise inside the pressure-resistant container 68 due to the cooling of the pressure-resistant container 68 was a curve as shown in FIG. That is, the pressure inside the pressure vessel 68 is increased by setting the pressure vessel 68 at −22 ° C. refrigerant 80 in the thermostat 78.
The pressure started to rise 15 minutes after the immersion, and the pressure increased to 141 MPa after 1 hour to reach an equilibrium state.

The set temperature of the constant temperature bath 78 is set to -5.degree.
10 ° C., −15 ° C., −20 ° C., and −22 ° C., and after immersing the pressure-resistant container 68 in the refrigerant 80 at each temperature for 30 minutes or more, the pressure inside the pressure-resistant container 68 was measured.
60MPa at -5 ° C, 103M at -10 ° C
It became 141 MPa at Pa and -15 degreeC--22 degreeC. The results are shown in FIG.
a) is shown together with the equilibrium curve A of water / ice.

As shown in FIG. 6, the result of the experiment was -15 ° C.
Although the water / ice equilibrium curve A is overlapped to the vicinity, the pressure inside the pressure vessel 68 does not rise even after the temperature is lowered. This experimental result is considered to indicate the following. That is, when the pressure vessel 68 is cooled, ice is generated at a temperature of 0 ° C. or less in the rubber balloon 70, and the volume of the rubber balloon 70 expands. As a result, the pressure inside the pressure vessel 68 increases accordingly,
The ethanol 72 in the pressure container 68 and the water and ice in the rubber balloon 70 are compressed. And the pressure container 68
The pressure generated inside lowers the freezing point of the water in the rubber balloon 70 according to Bridgman's equilibrium curve A. On the other hand, since the temperature of the pressure vessel 68 is continuously decreased, the generation of new ice in the rubber balloon 70, the increase in the pressure inside the pressure vessel 68, the ethanol 72 in the pressure vessel 68, and the inside of the rubber balloon 70. It is considered that the compression of water and ice and the freezing point of water in the rubber balloon 70 proceed simultaneously. While the unfrozen water exists in the rubber balloon 70, the temperature and the temperature
The pressure changes on the equilibrium curve A to the low temperature / high pressure side, and when the unfrozen water disappears, no new pressure is generated due to the freezing of the water. Departure, only the temperature drops. As in this experimental example, the ratio of 140 ml of water in the rubber balloon 70 and 27 ml of ethanol in the pressure-resistant container 68 indicates that the freezing of the water in the rubber balloon 70 has been almost completed at a temperature around -15 ° C. Conceivable.

[2. Sterilization by High Pressure] The pressurized samples a and b are separately accommodated in the pressure-resistant container shown in FIG. 3, and the pressure-resistant container is filled with water. After sealing b and water, the pressure-resistant container was put in a freezer set at various temperatures, cooled, and the change in the number of viable bacteria when each was held for 24 hours was examined.
The result is shown in FIG. In the figure, the broken line a indicates the sample a to be pressed.
(Yeast Chigosaccharomyces luxii for salt-tolerant miso
IAM 12880) was sealed in a pressure-resistant container and the pressure-resistant container was cooled. The result of the folding line b is that the sample to be pressurized b (non-salt-resistant yeast Saccharomyces cerevisiae IMF 42)
74) shows the result when the pressure-resistant container is cooled by sealing it in a pressure-resistant container, and the broken line a ′ shows the result when the sample a to be pressurized is put into the open container and the open container is cooled, and the broken line b ′ shows the result. And the results when the sample to be pressurized b is placed in an open container and the open container is cooled are shown.

As is clear from the results shown in FIG. 7, the survival rate of both yeasts decreased with decreasing temperature, and
At temperatures below ℃, it died completely. In contrast, when the temperature was reduced to normal pressure, the survival rate of the yeast did not change at all.

For comparison, a change in the number of viable bacteria when each of the samples to be pressed a and b was pressurized at room temperature was examined using a pressurizing test apparatus for food. The result is shown in FIG. In the figure, the fold line a ″ shows the result of pressing the sample to be pressed a at room temperature, and the fold line b ″ shows the result of pressing the sample to be pressed b at room temperature. From FIG. 8, it was found that a pressure of 200 MPa was required to kill yeast at room temperature.

Each of the other pressurized samples c to f was sealed in a pressure-resistant container, placed in a freezer set at a temperature of -20 ° C., cooled, and held for 24 hours. Of the number of viable bacteria was examined. The results are shown in Table 1 together with the results for the samples a and b to be pressed.

[0040]

[Table 1]

From the results shown in Table 1, all of the lactic acid bacteria, Escherichia coli and both koji molds were completely killed. In contrast,
Cooling the sample in an open container did not significantly alter the viability.

The killing factors of the microorganisms by the sterilization method according to the present invention are considered to be a sterilization effect by a low temperature below the freezing point and a sterilization effect by the high pressure. As shown in the above, the high survival rate is obtained, so that the sterilization effect by low temperature is not considered to be a major lethal factor. Therefore, it is considered that the killing of the microorganisms by the hermetic cooling in the pressure-resistant container is due to an increase in the pressure inside the pressure-resistant container due to the cooling below the freezing point. As shown in FIG.
MPa.

[0043]

According to the sterilization method of each of the inventions according to claims 1 to 7, it is possible to easily generate a high pressure without requiring a large-scale high-pressure generator, and to provide articles such as foods and medical tools, Biological fluids such as enzyme solutions and serum, and liquid pharmaceuticals can be effectively sterilized. In addition, when the sterilization apparatus according to each of the eighth and ninth aspects of the invention is used, a sterilization method having the above-described effects can be suitably performed.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view showing an example of a configuration of a sterilization apparatus used for performing a sterilization method according to the present invention.

FIG. 2 is a schematic longitudinal sectional view showing another configuration example of the sterilization apparatus.

FIG. 3 is a longitudinal sectional view showing a structure of a pressure-resistant container used in an experiment for generating high pressure.

FIG. 4 is a longitudinal sectional view showing an entire configuration of an apparatus used for measuring a pressure generated inside a pressure-resistant container.

FIG. 5 is a diagram showing an experimental result of high pressure generation inside a pressure vessel and showing a cooling time-generated pressure curve.

FIG. 6 is a diagram showing the relationship between the cooling temperature and the generated pressure.

FIG. 7 is a diagram showing the results of an experiment for examining the bactericidal effect by high pressure and showing the relationship between the cooling temperature and the number of viable bacteria.

FIG. 8 is a diagram showing an experimental result of examining a change in the number of viable bacteria when a sample to be pressurized is pressurized at room temperature, and showing a relationship between the pressure and the number of viable bacteria.

[Explanation of symbols]

 10, 20 Pressure-resistant container body 12, 30 Liquid inlet 14, 32 Sealing stopper 16 Plastic container 18, 28 Freezing medium (water) 22 Diaphragm 24 Freezing chamber 26 Sterilization chamber 34 Medical tool 36 Filling liquid (ethanol)

[Procedure amendment]

[Submission date] December 24, 1999 (1999.12.
24)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0036

[Correction method] Change

[Correction contents]

[2. Sterilization by High Pressure] The pressurized samples a and b are separately accommodated in the pressure-resistant container shown in FIG. 3, and the pressure-resistant container is filled with water. After sealing b and water, the pressure-resistant container was put in a freezer set at various temperatures, cooled, and the change in the number of viable bacteria when each was held for 24 hours was examined.
The result is shown in FIG. In the figure, the broken line a indicates the sample a to be pressed.
(Yeast Chigosaccharomyces luxii for salt-tolerant miso
IAM 12880) was sealed in a pressure-resistant container, and the pressure-resistant container was cooled. The broken line b shows the sample to be pressed b (non-salt-tolerant yeast Saccharomyces cerevisiae IAM 42).
74) shows the result when the pressure-resistant container is cooled by sealing it in a pressure-resistant container, and the broken line a ′ shows the result when the sample a to be pressurized is put into the open container and the open container is cooled, and the broken line b ′ shows the result. And the results when the sample to be pressurized b is placed in an open container and the open container is cooled are shown.

Claims (9)

[Claims] An object to be sterilized is housed in a pressure-resistant container, and the pressure-resistant container is filled with a liquid freezing medium to eliminate gas, and the object to be sterilized and the freezing medium are sealed in the pressure-resistant container. And then cooling the pressure vessel to freeze all or part of the freezing medium inside. 2. A sterilizing liquid is filled in a pressure-resistant container to eliminate gas, and the liquid to be sterilized is sealed in the pressure-resistant container. Then, the pressure-resistant container is cooled to remove all or one of the liquid to be sterilized inside. A sterilization method characterized by freezing a part. 3. A state in which a filling liquid for filling an object to be sterilized and its surroundings and a freezing medium in a liquid state are separated from each other by a deformable separating member and filled in a pressure-resistant container to exclude gas. A sterilization method comprising sealing an object to be sterilized, a filling liquid, and a freezing medium in a pressure-resistant container, and then cooling the pressure-resistant container to freeze all or a part of the internal freezing medium. 4. An object to be sterilized is housed in a deformable plastic container or bag, and the container or bag is filled with a filling liquid to eliminate gas, and the object to be sterilized is stored in the container or bag. After filling the sealed liquid with the filling liquid in a pressure container, the liquid container is filled with a freezing medium in a liquid state to eliminate gas, and then the object to be sterilized and the filling liquid are frozen in the pressure container. The sterilization method according to claim 3, wherein the medium is sealed. 5. The sterilizing liquid and the freezing medium in a liquid state are separated from each other by a deformable separating member, and the sterilizing liquid and the freezing medium are filled in the pressure-resistant container to eliminate the gas. A sterilization method comprising sealing a freezing medium and then cooling the pressure container to freeze all or part of the freezing medium inside. 6. A container in which a liquid to be sterilized is sealed in a container or a bag in a state in which the liquid to be sterilized is filled in a deformable plastic container or bag and gas is removed, and then stored in a pressure-resistant container. 6. The sterilization method according to claim 5, wherein the liquid to be sterilized and the freezing medium are sealed in the pressure-resistant container while the pressure-resistant container is filled with a liquid freezing medium to eliminate gas. 7. The sterilization method according to claim 1, wherein a salt solution that expands due to freezing and eutectic formation when cooled is used as the freezing medium. 8. A pressure-resistant container body capable of containing a liquid therein and having a liquid inlet formed therein, and the liquid inlet of the pressure-resistant container body is liquid-tight even when the internal pressure of the pressure-resistant container body increases. A sterilizer comprising: a hermetic plug that closes; 9. The interior is partitioned into two chambers by a diaphragm, one of which is sealed and filled with a freezing medium therein, and the other of which is capable of storing a liquid inside the other chamber. A pressure-resistant container body having a liquid inlet formed therein, and a hermetic plug that closes the liquid inlet of the pressure-resistant container body in a liquid-tight manner even when the internal pressure of the pressure-resistant container body increases. Sterilizing equipment.