JP2736605B2 - Liquid material sterilization method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for disinfecting a liquid material, and more particularly to a method for disinfecting a liquid material for killing microorganisms that have been mixed without heat sterilization.

[0002]

2. Description of the Related Art Food and beverages are required to be able to be stored for a certain period of time after production. It is necessary to perform some kind of sterilization treatment at any stage of the manufacturing process in order to prevent deterioration of food and drink and spoilage due to proliferation of microorganisms (such as bacteria) derived from raw materials and microorganisms mixed in the manufacturing process. In addition, some raw materials such as industrial raw materials, pharmaceuticals and cosmetics, intermediates and products also need to be storable. For example, many pharmaceuticals and cosmetics cannot be heat-sterilized. Is added.

[0003] As a general method of sterilizing a liquid material, a heat sterilization method is used. In particular, heat sterilization is used for liquid foods and drinks. This sterilization method is carried out at a temperature of about 110 ° C. using only pressurized saturated steam, and is extremely safe and has a very high sterilizing effect (degree of killing of microorganisms). Therefore, in recent years, long life products have been developed by utilizing this. However, in the heat sterilization method, food and drink are heated to a high temperature to kill microorganisms mixed therein with heat, and the food and drink often deteriorate. For example, when a food containing a protein is subjected to heat sterilization treatment, the protein may be denatured to lower the flavor of the food or to impair the specific function of the protein. In addition, vitamins contained in foods and drinks, pharmaceuticals, and the like are broken by heat and lose their effectiveness, and the quality of foods and drinks, pharmaceuticals, and the like deteriorates. For this reason, for the purpose of preserving food, it is common practice to keep the food at around 5 ° C. during the storage or distribution process, and to add a preservative or an antibacterial agent to the food in order to prevent spoilage and deterioration caused by microorganisms. I have.

[0004] In order to avoid deterioration in the quality of foods and drinks due to heating, an ultra-high pressure sterilization method performed at a relatively low temperature has been proposed. For example, Japanese Patent Laid-Open Publication No.
This is a method of applying a hydrostatic pressure of 00 to 10000 atmospheres to cause damage to cell walls, cell membranes, and the like of microorganisms in the object to be treated, and at the same time, denature microorganisms by denaturing intracellular proteins. However, since this method uses an extremely high hydrostatic pressure of 5000 atm or more, an extremely expensive ultrahigh pressure generating device and an ultrahigh pressure pressure vessel are required, and the equipment cost including safety measures becomes extremely expensive. , The utility cost is also high. Furthermore,
Some people have questioned the bactericidal effect of high hydrostatic pressure on protein-containing foods, and are currently used only in foods and drinks that do not contain proteins such as jams and juices.

[0005] As a sterilization method performed at a relatively low temperature, Japanese Patent Application Laid-Open No. 5-76329 discloses that a liquid material contains 2,500 kg.
A method for disinfecting a liquid material which is subjected to a treatment of applying a high hydrostatic pressure of / cm ² or more and a rapid decompression cell crushing treatment from a high pressure is disclosed. Although this method is lower than the pressure of the method described in JP-A-2-313577,
This requires a process of applying an ultra-high hydrostatic pressure of 500 kg / cm ² or more. For this purpose, the liquid material is put in a container for a retort pouch or the like, and sealed, and then the liquid material is sealed.
It is necessary to apply a hydrostatic pressure of 0 kg / cm ² or more. This publication points out that long-term treatment is required when the hydrostatic pressure is less than 2500 kg / cm ² . This method is a batch processing method and is not suitable for processing a large amount of liquid material.

Further, NATURE, January 6, 1951
Date, No. On pages 4236, pages 33-34, carbon dioxide is introduced into a vessel containing a culture medium containing E. coli under a pressure of about 40 atm, the pressure in the vessel is kept constant, and then instantaneously released to atmospheric pressure. It has been reported that Escherichia coli is destroyed by this (burst phenomenon). This report relates to eluting intracellular metabolites by destroying Escherichia coli, but does not describe the bactericidal effect of Escherichia coli.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a liquid material that requires a sterilization treatment without damaging the flavor and texture of foods and drinks and to damage the active ingredients contained in the liquid material. It is an object of the present invention to provide a sterilization method suitable for mass production that can be sterilized at a relatively low temperature using an inexpensive and easy-to-operate apparatus.

[0008]

According to the present invention, a liquid substance containing microorganisms is obtained by a step of absorbing carbon dioxide into the liquid substance under pressure ("absorption step") and an absorption step. The process of rapidly reducing the pressure of a pressurized liquid material that absorbs carbon dioxide (“decompression process”) is repeated alternately to kill at least some of the microorganisms mixed in the liquid material And a method for sterilizing a liquid material.

The preferred embodiments of the present invention are as follows. (1) In the above-mentioned depressurization step, after the liquid material is compressed to a pressure higher than that in the absorption step, the pressure is rapidly reduced.
A method for sterilizing the above liquid material.

(2) The above-mentioned method for sterilizing a liquid material, wherein the pressure of the liquid material is rapidly reduced and a mechanical impact force is applied to the liquid material in the depressurizing step.

(3) The method for sterilizing a liquid material according to the above, wherein the liquid material is compressed to a pressure higher than that in the absorption step in the pressure reduction step, and then rapidly reduced to the pressure in the absorption step.

(4) The above-mentioned absorption step is carried out using carbon dioxide
The method for sterilizing the above liquid material under a partial pressure of up to 70 atm.

(5) The above-mentioned absorption step is carried out using carbon dioxide
Performed under a partial pressure of ~ 70 atm.
The above-mentioned method for sterilizing a liquid material, wherein the liquid material is compressed to 200 to 3000 atmospheres and then rapidly reduced to the pressure in the absorption step.

(6) The above absorption step is performed in the absorption tank, and the pressurized liquid material absorbing carbon dioxide from the absorption tank is sent to a rapid decompression device to perform the above decompression step. Returning the discharged material to the absorption step, extracting a part of the liquid material as a sterilized product from the liquid circulation path, and supplying an amount of new liquid material corresponding to the extracted product to the absorption tank. The method for sterilizing the above liquid material, which is performed continuously.

(7) The method for sterilizing a liquid material, wherein the absorption step is performed at a temperature of 5 to 100 ° C.

The sterilization method of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a flow sheet schematically showing one embodiment of the present invention.

In FIG. 1, an absorption tank 1 with a jacket is provided.
The liquid 3 containing microorganisms from the liquid supply pipe 2
And carbon dioxide is supplied from a carbon dioxide supply pipe 4, the inside of the absorption tank 1 is maintained in a pressurized state of carbon dioxide, and the liquid substance 3 absorbs carbon dioxide. Excess carbon dioxide can be exhausted from the exhaust pipe 5. The liquid 3 in the absorption tank 1 is maintained at a predetermined temperature by a liquid medium passing through the jacket 6 of the absorption tank 1.

The liquid material having absorbed carbon dioxide discharged from the lower part of the absorption tank 1 is sent to a high-pressure pump 8A of a rapid decompression device 8 through a pipe 7, and is pressurized by a high-pressure pump 8A to a chamber 8B. Sent. Liquid material is in chamber 8
The pressure is rapidly reduced in B, through tube 9 and through heat exchanger 1
After being cooled by 0, it is returned to the absorption tank 1 through the pipe 11. A part of the liquid passing through the pipe 11 is taken out of the pipe 12 as a product.

The liquid to be treated in the present invention is not particularly limited as long as it is a liquid containing microorganisms. As a liquid material that is particularly effectively treated according to the present invention, when subjected to heat sterilization, the flavor is reduced or deteriorated or browned, or the function of the contained active ingredient is reduced or lost. Liquid foods and drinks, and substances with high thermal decomposition properties (eg, vitamins, sugar derivatives (oligosaccharides,
Polysaccharides), hormones, steroids,
(E.g., alkaloids, etc.) and easily perishable, such as industrial raw materials, raw materials for pharmaceuticals and cosmetics, intermediate products and products. This liquid material preferably has a viscosity of 10,000 centipoise or less at 25 ° C., and examples thereof include a solution, suspension, dispersion, emulsion, and paste. Further, the medium is not particularly limited as long as it can absorb carbon dioxide, for example,
In the case of liquid foods and drinks, there are generally those containing water as a main component (for example, water, an aqueous ethanol solution, an emulsion of water-fat and the like), and those containing a liquid fat as a main component.

Particularly preferred examples of such liquids include liquid foods and drinks including liquid foods, liquid seasonings, beverages, and the like. Specific examples thereof include soymilk, soup, whipped cream, jam, Honey, dressing,
Examples include soy sauce, juice, sake, beer, juice, milk, drinks (containing vitamins, amino acids, etc.), lactic acid drinks and the like.

In order to maintain the temperature of the contents of the absorption tank 1 at a predetermined temperature, a heat medium or a refrigerant is passed through the jacket 6 of the absorption tank 1. The absorption step in the present invention is generally 5 to 100.
C., preferably 10-80.degree. C., and the medium to be passed through the jacket 6 is selected according to the desired temperature of the absorption step. The medium is generally water or brine, but may be other suitable media such as oil. When the temperature of the liquid material in the absorption step is lower than the above range, the viscosity of the liquid material becomes high, and depending on the case, solidification or solid precipitation tends to make it difficult to transfer the liquid material in the system. If it is higher than the above range, the components of the liquid material may be altered or decomposed, and the quality of the liquid material may be degraded.

A liquid material 3 is supplied from a liquid material supply pipe 2 into the absorption tank 1. Further, carbon dioxide is supplied from the carbon dioxide supply pipe 4 into the absorption tank 1. The outlet of the carbon dioxide supply pipe 4 is located near the bottom in the absorption tank 1, and the carbon dioxide that has flowed out of the carbon dioxide supply pipe 4 rises by bubbling through the liquid material 3 (at this time, absorption). Exhausting carbon dioxide gas from the exhaust pipe 5 while maintaining the pressure in the tank 1 facilitates bubbling), during which time the carbon dioxide is sufficiently absorbed by the liquid material 3. Carbon dioxide is generally supplied in a state of carbon dioxide gas, but may be supplied in a state of liquefied carbon dioxide or in a supercritical state. Carbon dioxide may contain an inert gas such as nitrogen, but the concentration of carbon dioxide is generally preferably at least 20% by weight, particularly preferably at least 50% by weight. The partial pressure of carbon dioxide in the absorption tank 1 is preferably 5 to 70 atm, particularly preferably 10 to 50 atm. If the partial pressure of carbon dioxide is lower than the above range, the sterilizing effect is reduced, and there is a tendency that it is necessary to lengthen the treatment time to sufficiently sterilize, and the partial pressure of carbon dioxide is lower than the above range. Even if it is increased, further improvement of the sterilization effect is not expected much, and it is necessary to further increase the pressure of the apparatus.

In the absorption tank 1, a part of carbon dioxide is extracted from the exhaust pipe 5, and the carbon dioxide is bubbled into the liquid, so that the carbon dioxide is sufficiently absorbed by the liquid. A liquid mixer may be stirred by providing a stirrer in the absorption tank 1.

The liquid material 3 in the absorption tank 1 is discharged from the lower part of the absorption tank 1, sent to the high pressure pump 8A of the rapid pressure reducing device 8 through the pipe 7, pressurized to a desired pressure, and sent to the chamber 8B. The pressure of the liquid when entering the chamber 8B is preferably 200 to 3000 atm, particularly preferably 500 to 2000 atm. Next, the pressure of the liquid material is rapidly reduced in the chamber 8B. As described above, most of the liquid discharged from the chamber 8B is returned to the absorption tank 1 again. Therefore, the pressure of the liquid discharged from the chamber 8B is slightly higher than the pressure in the absorption tank 1 in the chamber 8B. It is preferable to reduce the pressure. Of course, chamber 8B
The pressure of the liquid substance coming out of the absorption tank 1 may be lower than the pressure in the absorption tank 1. In this case, the liquid substance is sent to the absorption tank 1 by applying a pressure higher than the pressure in the absorption tank 1.

It is generally preferred that the time for the liquid to pass through the chamber 8B is within about one second. That is, the pressure is rapidly decreased from the pressure when entering the chamber 8B to the pressure when exiting the chamber 8B, preferably within about one second. The chamber 8B only needs to have a structure capable of rapidly reducing the pressure of the liquid material pressurized by the high-pressure pump 8A, and is provided with an orifice for blowing the pressurized liquid material into the chamber 8B. It may be something. In the chamber 8B, the pressure is rapidly reduced, the flow of the liquid material is divided into two, and the respective flows collide with each other, so that a mechanical impact force (shear force) is applied to the liquid material.
May be given. If the pressure of the liquid material when entering the chamber 8B is lower than the above range, the sterilization effect due to a rapid pressure drop (in some cases, further mechanical impact force) tends to decrease, and the pressure is set to be lower than the above range. Even if it is increased, a further increase in the sterilizing effect is not expected, and a higher pressure of the device is required.

There is a type of a rapid decompression device 8 in which the high-pressure pump 8A and the chamber 8B are integrated into one unit. Examples of such a device include trade names such as a microfluidizer, a nanomizer, and Menton-Gaulin. Some are commercially available. Therefore, the high pressure pump 8
Although the liquid material may be pressurized to a very high pressure by A, the size of the rapid decompression device 8 is relatively small because the residence time in the rapid decompression device 8 is very short, Is very small.

The liquid discharged from the chamber 8B passes through the pipe 9, is cooled by the heat exchanger 10, is returned to the absorption tank 1 through the pipe 11, and is subjected to a carbon dioxide absorbing step. In this way, the liquid material circulates through the absorption tank 1 and the rapid decompression device 8, and is repeatedly applied to the absorption step and the decompression step.

A part of the liquid passing through the pipe 11 is taken out of the pipe 12 as a product (sterilized liquid), and
The liquid material of the raw material corresponding to the amount of the product taken out of the liquid is supplied from the liquid supply pipe 2 to the absorption tank 1. Further, carbon dioxide equivalent to the consumed carbon dioxide is supplied from the carbon dioxide supply pipe 4 to the absorption tank 1, and the internal pressure of the absorption tank 1 is maintained at a predetermined pressure. By continuously taking out the product from the pipe 12 and supplying the liquid substance to the absorption tank 1,
The liquid material sterilization method of the present invention can be continuously performed.

In the method for sterilizing a liquid material of the present invention, the mechanism for sterilizing microorganisms contained in the liquid material is not necessarily clear, but is presumed as follows. That is,
Since carbon dioxide is easily absorbed in an aqueous medium, in the absorption step, carbon dioxide is absorbed into the cells of the microorganism under pressure, and the cells that have absorbed this carbon dioxide are
Due to the rapid pressure drop in the decompression process, the carbon dioxide absorbed under pressure inside the cell rapidly gasifies and expands (causing a burst phenomenon), thereby destroying the cell wall and cell membrane of microorganisms. As a result, it is considered that microorganisms are killed. It is considered that by applying a mechanical impact force to the liquid material in the decompression step, the microorganisms can be killed more efficiently.

In the liquid sterilization method of the present invention, carbon dioxide under pressure is used, but the pressure is much lower than the pressure of 5000 atm or more as in the conventional ultrahigh pressure sterilization method. It is clear that the sterilization mechanism of the present invention is completely different from the ultrahigh-pressure sterilization method in which microbial cell membranes are damaged by ultrahigh pressure and sterilized. Although a pressure of 3000 atm or less may be applied in the depressurizing step of the present invention, the time during which the liquid is subjected to high pressure in the depressurizing step is extremely short as described above. I can't imagine.

[0031]

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples.

[Example 1] Escherichia coli and Saccharomyces cerevis each as cells in sterile physiological saline.
Iae or Bacillus subtilis (spores) were dispersed at ice temperature to prepare three kinds of bacterial cell dispersions. The initial cell count of the cells in each cell dispersion was as shown in Table 1.

As a sterilizer, an apparatus as shown in FIG. 1 was used. However, a pressure-resistant container having an internal volume of 500 mL is used as the absorption tank 1 and a Nanomizer (model LA-30 or LA-5 manufactured by Nanomizer Co., Ltd.) is used as the rapid decompression device 8.
2) was used. 150 mL of the microbial cell dispersion liquid is introduced into the absorption tank 1 from the liquid supply pipe 2, and water having the temperature shown in Table 1 is circulated through the jacket 6 of the absorption tank 1 so that the temperature of the dispersion liquid in the absorption tank 1 becomes substantially constant. Kept. Carbon dioxide gas from a cylinder was blown into the bacterial cell dispersion through the carbon dioxide supply pipe 4 to maintain the pressure in the absorption tank 1 at about 40 atm. At this time, absorption tank 1
By exhausting carbon dioxide from the exhaust pipe 5 while maintaining the internal pressure, bubbling of carbon dioxide was caused and the dispersion was stirred. The microbial cell dispersion is sent from the lower part of the absorption tank 1 to the high-pressure pump 8A of the nanomizer 8, and the microbial cell dispersion is pressurized so that the outlet pressure of the high-pressure pump 8A becomes the pressure shown in Table 1. 8B, and the pressure of the bacterial cell dispersion was rapidly reduced (the chamber passage time was about 1 second or less) so as to be about 40 atm at the outlet of the chamber 8B. The bacterial cell dispersion discharged from the chamber 8B was cooled to the temperature of the bacterial cell dispersion in the absorption tank 1 by the heat exchanger 10, and then returned to the absorption tank 1. Table 1 shows the flow rate of the bacterial cell dispersion passing through the nanomizer 8.

After maintaining the above conditions and continuing the circulation of the bacterial cell dispersion for the circulation time shown in Table 1, the bacterial cell dispersion was sampled, and agar medium was used for 35 days at 35 ° C. for the number of days shown in Table 1.
After culturing, the number of remaining bacteria was measured, and the viability was calculated by the following equation. Viable bacteria rate = number of remaining bacteria / number of initial bacteria

The viable cell ratio is shown in Table 1. In each case, the number of remaining bacteria is 10 cells / mL or less (detection limit) or less, and it is considered that the bacteria are sterilized.

[0036]

[Table 1]

Comparative Example 1 Three kinds of bacterial cell dispersions were prepared in the same manner as in Example 1. The initial number of cells in each cell dispersion was as shown in Table 2.

Using the apparatus used in Example 1, 150 mL of the bacterial cell dispersion was introduced into the absorption tank 1 from the liquid supply pipe 2, and water having the temperature shown in Table 2 was circulated through the jacket 6 of the absorption tank 1. The temperature of the dispersion in the absorption tank 1 was kept almost constant. Carbon dioxide gas from a cylinder is blown into the bacterial cell dispersion through the carbon dioxide supply pipe 4 to reduce the pressure in the absorption tank 1 to about 40
Atmospheric pressure was maintained. At this time, the carbon dioxide gas was evacuated from the exhaust pipe 5 while maintaining the pressure in the absorption tank 1, thereby causing bubbling of the carbon dioxide gas and stirring the dispersion. This state was continued for the absorption tank processing time shown in Table 2, and the valve in the exhaust pipe 5 was fully opened to immediately release the pressure in the absorption tank 1 to the atmospheric pressure (within about one second).

The bacterial cell dispersion in the absorption tank 1 was treated in the same manner as in Example 1, the number of remaining bacteria was measured, and the viability was calculated. Table 2 shows the results.

[0040]

[Table 2]

From the results in Table 2, it can be seen that when the pressure treatment with carbon dioxide was performed and the pressure was rapidly reduced once, and the absorption step and the pressure reduction step were not repeated as in the present invention, the sterilization efficiency was reduced. It is clear that it is significantly lower. That is,
When the cells were Esherichia coli, the treatment time was 10 times longer than in Example 1, and the cells were Saccharomyces cerevi
In the case of siae, the viability rate is remarkably high even when the treatment time is quadrupled as compared with Example 1, and it is necessary to increase the treatment time by 12 times in order to sterilize to the same degree as in Example 1. ,
When the cells are Bacillus subtilis (spores),
Even when the treatment time is quadrupled compared to Example 1, the viability rate is remarkably high, and in order to sterilize to the same degree as in Example 1, it is necessary to increase the absorption tank temperature and quadruple the treatment time. .

Comparative Example 2 Three kinds of bacterial cell dispersions were prepared in the same manner as in Example 1. The initial number of cells in each cell dispersion was as shown in Table 3.

Using the apparatus used in Example 1, 150 mL of the bacterial cell dispersion was put into the absorption tank 1 from the liquid supply pipe 2, and water having the temperature shown in Table 3 was circulated through the jacket 6 of the absorption tank 1. The temperature of the dispersion in the absorption tank 1 was kept almost constant. No carbon dioxide gas was supplied to the absorption tank 1. The bacterial cell dispersion in the absorption tank 1 was passed through the nanomizer at the nanomizer pressure and flow rate shown in Table 3 in the same manner as in Example 1,
Circulated through the absorption tank. After maintaining the above conditions and continuing the circulation of the bacterial cell dispersion for the circulation time shown in Table 3, the bacterial cell dispersion in the absorption tank 1 was treated in the same manner as in Example 1 to determine the number of remaining bacteria. Was measured, and the viable cell ratio was calculated. Table 3 shows the results.
Shown in

[0044]

[Table 3]

From the results shown in Table 3, when the treatment was performed in the same manner as in Example 1 except that the pressure treatment with carbon dioxide was not performed,
When the cells are Esherichia coli, the results are the same as in Example 1. However, when the cells are Saccharomyces cerevisiae and Bacillus subtilis (spores), the treatment time is the same as in Example 1. It is clear that the rate is extremely high and cannot be sterilized sufficiently.

Example 2 Soybeans were added to tap water at room temperature for about 15 minutes.
After immersion and swelling for a period of time, the mixture was filtered. Tap water was added to the swollen soybeans, and crushed using a juicer mixer for about 2 minutes to prepare raw gou, and the raw gou was squeezed to prepare soymilk. The freshly squeezed soy milk contained about 10 ⁶ cells / mL.

Using the sterilizing apparatus used in Example 1, 150 mL of soymilk was put into the absorption tank 1 from the liquid supply pipe 2,
Water at 60 ° C. was circulated through the jacket 6 of the absorption tank 1 to keep the temperature of the dispersion in the absorption tank 1 almost constant. Carbon dioxide gas from the cylinder was blown into the soymilk through the carbon dioxide supply pipe 4 to maintain the pressure in the absorption tank 1 at about 40 atm. At this time, the carbon dioxide gas was evacuated from the exhaust pipe 5 while maintaining the pressure in the absorption tank 1, thereby causing bubbling of the carbon dioxide gas and stirring the dispersion. The soymilk is sent from the lower part of the absorption tank 1 to the high-pressure pump 8A of the nanomizer 8 at a flow rate of 170 mL / min, and the soymilk is pressurized so that the outlet pressure of the high-pressure pump 8A becomes approximately 2000 atm. Then, the pressure of the soymilk was rapidly decreased (the passage time in the chamber was about 1 second or less) so that the pressure became about 40 atm at the outlet of the chamber 8B. After cooling the soymilk discharged from the chamber 8B to about 60 ° C. in the heat exchanger 10, the absorption tank 1
Back to.

After maintaining the above conditions and circulating the soy milk for 15 minutes to carry out a sterilization treatment, the soy milk in the absorption tank 1 was treated in the same manner as in Example 1, and the number of residual bacteria was measured. The viable cell rate was calculated. The viable cell rate was 10 ^-5 and a very high bactericidal effect was obtained.

Example 3 Saccharomyces cerevisiae was added to an aqueous solution containing 0.01% by weight of vitamin B ₁ of 10 ⁶ bacteria.
The solution was dispersed so as to obtain an aqueous vitamin B ₁ solution.

A sterilization treatment of the vitamin B ₁ aqueous solution was performed at 40 ° C. in the same manner as in Example 2 except that the above-mentioned vitamin B ₁ aqueous solution was used instead of soy milk.

After maintaining the above conditions and circulating a vitamin B ₁ aqueous solution for 15 minutes to perform a sterilization treatment, the absorption tank 1
The aqueous vitamin B ₁ solution was treated in the same manner as in Example 1, the number of remaining bacteria was measured, and the viable cell ratio was calculated. The viable cell rate was 10 ⁻⁵ or less (below the detection limit), indicating that the bacteria were completely sterilized.

[0052] residual ratio of vitamin B ₁ vitamin B ₁ in an aqueous solution obtained by this sterilization is 100%, and it was confirmed that vitamin B ₁ in this sterilization process was not degraded at all.

It is known that when heat treated at 120 ° C. for 15 minutes, the residual ratio of vitamin B ₁ is about 20%. In this example, it was confirmed that vitamin B ₁ can be completely sterilized without decomposing vitamin B ₁ . .

[0054]

According to the method for sterilizing a liquid material of the present invention, liquid foods (liquid foods, liquid seasonings, beverages, etc.), liquid industrial raw materials,
Microorganisms contained in liquids, such as liquid pharmaceuticals and liquid cosmetics, without lowering or worsening or browning the flavor of the liquids, and without reducing or losing the function of the contained active ingredient. This has a remarkable effect that sterilization can be performed almost completely in a short time. In particular, the method for sterilizing a liquid material of the present invention has a remarkable effect that it is extremely effective for liquid foods and drinks containing proteins, which were difficult to sterilize by the conventional pasteurization method.

Further, in the method for sterilizing a liquid material according to the present invention, it is not necessary to use an expensive ultra-high pressure device, and it can be performed continuously, so that the equipment cost is low and the safety of operation is high. Also, there is a remarkable effect that the production efficiency is high.

[Brief description of the drawings]

FIG. 1 is a flow sheet schematically showing an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Absorption tank 2 Liquid supply pipe 3 Liquid 4 Carbon dioxide supply pipe 5 Exhaust pipe 6 Jacket 7 Tube 8 Rapid decompression device 8A High pressure pump 8B Chamber 9 Tube 10 Heat exchanger 11 Tube 12 Tube

 ──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Toshihide Oda 6-8-11 Hiyoshidai, Tomisato-cho, Inba-gun, Chiba Prefecture (56) References JP-A-5-130854 (JP, A) JP-A-5-7480 ( JP, A) JP-A-63-82667 (JP, A)

Claims (6)

(57) [Claims] 1. A step of causing a liquid substance containing microorganisms to absorb carbon dioxide into the liquid substance under pressure, and the step of removing the pressurized liquid substance absorbing carbon dioxide obtained in this step. A method for sterilizing a liquid material, wherein at least a part of microorganisms mixed in the liquid material is killed by alternately and repeatedly applying the pressure to the step of rapidly reducing the pressure. 2. The method according to claim 1, wherein the step of absorbing carbon dioxide is performed under a partial pressure of carbon dioxide of 5 to 70 atm. 3. A step of absorbing a liquid material containing microorganisms under pressure to absorb carbon dioxide into the liquid material, and the step of applying a pressurized liquid material absorbing carbon dioxide obtained in this step to a higher pressure. And a step of rapidly reducing the pressure after compression to at least partially kill microorganisms mixed in the liquid material. 4. The method according to claim 3, wherein the step of absorbing carbon dioxide is performed under a partial pressure of 5 to 70 atm of carbon dioxide. 5. A step of absorbing a liquid material containing microorganisms under pressure to absorb carbon dioxide into the liquid material, and applying the pressurized liquid material absorbing carbon dioxide obtained in this step to a higher pressure. And then applying a mechanical impact force to the liquid material, while rapidly reducing the pressure, thereby at least partially killing the microorganisms mixed in the liquid material by repeatedly applying the same. A method for disinfecting a liquid material. 6. The method for sterilizing a liquid material according to claim 5, wherein the step of absorbing carbon dioxide is performed under a partial pressure of 5 to 70 atm of carbon dioxide.