JPH0657236B2 - High pressure liquid sterilizer - Google Patents

Description

The present invention relates to a high-pressure liquid sterilizer that sterilizes a liquid by applying high pressure, and is extremely useful for sterilizing water, milk, etc.

In manufacturing beverages, foods, cosmetics, medical materials, pharmaceuticals, etc., sterilization is required from the viewpoint of hygiene and preservation.

Well-known conventional liquid sterilizers include those that use heat, those that use chemicals, and those that irradiate with radiation or ultraviolet rays, but any of these may lead to deterioration in quality.

On the other hand, for example, Japanese Patent Publication No. 50-34117, Japanese Patent Publication No. 55-50671,
Japanese Unexamined Patent Publication (Kokai) No. 57-22679 discloses a combination of heat and pressure for sterilization. But these are 65
Heating above ℃ and pressurization below 12 kgf / cm ^{2 due} to the relatively low pressure are carried out, which is insufficient in terms of preventing quality deterioration and sterilizing effect.

Further, Japanese Patent Publication No. 56-24539 discloses a method of sterilizing by suddenly changing the pressure from a reduced pressure to a positive pressure, but this requires a vacuum pump, the operation is complicated, and moreover it consumes an inert gas. Therefore, there is a problem that it is costly.

The present invention has been made in view of such circumstances, and an object thereof is to provide a sterilizer that does not cause quality deterioration, can obtain a high sterilization effect, and is easy to operate and inexpensive. And

Thus, according to the present invention, in a high-pressure liquid sterilizer for sterilizing a liquid to be treated under a high pressure state, a container for containing the liquid to be treated, a piston for pressurizing the liquid to be treated in the container, and the liquid to be treated. A high-pressure liquid sterilization apparatus comprising: a liquid supply unit that supplies the liquid to the container; and a liquid discharge unit that is connected to the container and discharges the liquid to be treated after being pressurized and sterilized by the piston. Will be provided.

In the above, the liquid to be treated is, for example, milk, juice, soup, drink, preservative water for disaster prevention, medicine, sterilizing water for medical use, drinking water / cleaning water for aseptic animal breeding, animal cell mass culture medium, drug, Examples include injection solutions.

The pressure applied to the liquid to be treated is, for example, 500 kg.
f / cm ² or more, preferably 2000 kgf / cm ² to 4
It is 000 kgf / cm ² . Pressurization time is 5 minutes to 25
Minutes are preferable, and the pressure may be applied continuously or intermittently, but it is preferable to apply pressure intermittently. The reason why the container and the piston are used is that they are most suitable for intermittently applying a very high pressure of 500 kgf / cm ² or more.

The temperature of the liquid to be treated is in the normal temperature range (5 ° C to 3 ° C).
5 ° C.), but it is preferable that the temperature range is below the temperature at which protein denaturation occurs (about 60 ° C.) and above the optimal temperature for survival of the microorganism to be sterilized. For example, when the sterilization target is Escherichia coli, the temperature is preferably 40 ° C to 50 ° C.

Examples of sterilization targets to which the present invention can be applied include Escherichia coli, Staphylococcus, Bacillus subtilis, Salmonella, and Botulinum.

Hereinafter, embodiments will be described with reference to the drawings.

Here, FIG. 1 is a structural explanatory view showing an example of a high-pressure liquid sterilizer according to an embodiment of the present invention, FIG. 2 is an external view of an example of an object to be treated, and FIG. 3 is a graph showing pressure and viability of E. coli. A graph of data showing the relationship, FIG. 4 is a graph of data showing the relationship between temperature and the survival rate of Escherichia coli, FIG. 5 is a graph of data showing the relationship between the pressurizing time and the survival rate of E. coli, and FIG. 6 is constant. FIG. 7 is a graph showing a change in survival rate when pressure is applied continuously for a period of time and when pressure is applied intermittently, FIG. 7 is a configuration explanatory view of another example of an apparatus for carrying out the present invention, and FIG. It is a structure explanatory view of the further another example of the apparatus which implements.

In the high-pressure liquid sterilizer 1'shown in FIG. 1, the pressure vessel 2'contains the liquid to be treated 20 supplied through a pipe line 24 formed in the piston 4 '. The liquid 20 to be treated is stored in the hydraulic cylinder 5 while the valve 23 provided in the pipe 25 connected to the pressure vessel 2'and the valve 22 provided in the pipe 24 are closed. It is pressurized by a driven piston 4'and kept at a predetermined temperature T by a constant temperature bath 7 equipped with a heating / cooling block 8 and a stirrer 9. The pressure P of the liquid to be treated 20 can be obtained by converting the output of the oil pressure gauge 6, and the temperature T can be obtained from the output of the temperature sensor 10.

According to the high-pressure liquid sterilizer 1 ', the liquid to be treated 20 is supplied from the tip of the piston 4'into the pressure vessel 2'through the liquid feed pump 21, the valve 22 and the pipe 24, and After being pressurized and sterilized, it is configured to be taken out from the bottom of the pressure vessel 2'through the valve 23 and the conduit 25.

In this high-pressure liquid sterilizer 1 ', first the valves 22, 23
And the liquid feed pump 21 is operated to fill the liquid 20 to be treated in the pressure vessel 2 '. Next, after closing the valves 22 and 23, the hydraulic cylinder 5 is operated to pressurize for a predetermined time and then return to normal pressure again. Next, the valves 22 and 23 are opened and the liquid delivery pump 21
To supply the liquid 20 to be treated in a small amount (for example, about the volume of the conduit 24 from the valve 22 to the tip of the piston 4 '). As a result, a small amount of the sterilized liquid to be treated is extruded from the conduit 25.

On the other hand, the valves 22 and 23 are closed again and pressurized in the same manner as above,
Hereinafter, if the same operation is repeated, a small amount of the sterilized liquid to be treated is obtained from the pipe 25 periodically and continuously. The reason why the liquid to be treated 20 is supplied little by little is to prevent the unsterilized liquid to be treated 20 from reaching the conduit 25, but as a result, the liquid to be treated 20 has been pressurized several times. After that, it will be pushed out of the pipeline 25,
There is an advantage that a more reliable bactericidal effect can be obtained.

On the other hand, the object to be treated 11 shown in FIG.
5992 was mixed with water so as to have a concentration of 10 ⁸ cells / ml, and 4 ml of the bacterial solution was sealed in a plastic tube. A large number of the objects to be treated 11 were prepared and previously stored in the pressure vessel 2 '. After putting it in water etc. to the predetermined temperature T,
The object to be treated 1 is made by increasing the pressure of water or the like by the hydraulic cylinder 5.
Apply pressure P to 1.

The viability of Escherichia coli in the bacterial solution subjected to the above pressure treatment is determined by the plate smearing method of quantitative culture (slightly smearing the bacterial solution on an agar plate and allowing it to stand at 37 ° C overnight to grow one bacterium. Then, the number of the formed bacterial groups was visually counted to examine the number of the bacteria in the bacterial solution), and the results shown in FIGS. 3 to 6 were obtained.

FIG. 3 shows the relationship between the pressure P and the survival rate when the pressure P is continuously applied for 5 minutes, where a, b, c, c ′, d,
d'is the temperature T of 5 ° C, 20 ° C, 40 ° C, 40
C, 50 ° C., 50 ° C.

Fig. 4 shows the relationship between the temperature T and the survival rate when the pressure P is 500 kgf / cm ^2, and the pressure P is 1000 kg.
The relationship between the temperature T and the survival rate when f / cm ² is f, g,
As shown in h, e, f, g, and h are pressures applied continuously for 5 minutes, 5 minutes, 15 minutes, and 25 minutes, respectively.

In FIG. 5, the pressure P is 1000 kgf / cm ² and the temperature T is 2
The relationship between the pressurization time and the survival rate at 0 ° C is shown in i,
The pressure P is 2000 kgf / cm ² and the temperature T is 50 ° C.
The relationship between the pressurizing time and the survival rate in the case of is shown in j.

FIG. 6 shows the relationship between the pressure P and the survival rate when the pressure P is continuously applied for 5 minutes when the temperature T is 20 ° C.
(This is the same as b shown in FIG. 3), on the other hand, after applying the pressure P for 1 minute, the atmospheric pressure (1 kgf /
The relationship between the pressure P and the survival rate when the process of returning to cm ² ) is repeated 5 times is shown in l. The temperature T is set to 20 ° C. and the pressure P is set to 4000 kgf / cm ² and pressure is applied for 3 minutes, and then 30
Survival rate after returning to normal pressure for 5 times was repeated m
In addition, the temperature T is 50 ° C and the pressure P is 2000 kgf /
The survival rate is shown at point n when the pressure was increased to cm ² for 1 minute and then returned to normal pressure for 30 seconds, which was repeated 5 times.

Considering the graphs in FIGS. 3 to 6, the pressure P is 500
It can be seen that an effective bactericidal effect can be obtained by setting kgf / cm ² or more. As a specific example, for example, the survival rate 1 /
When 2 is used as an effective criterion, it is effective if the temperature T is set to 45 ° C. or more and a pressure of 500 kgf / cm ² or more is continuously applied for 5 minutes or more. If the pressurization time is extended or the pressurization is intermittently performed, the temperature T is further lowered to obtain T = 20.
It is also effective at ℃.

Further, the temperature T is set to 40 ° C. or higher and the pressure P is set to 30.
If it is set to 00 kgf / cm ² or more, complete sterilization can be performed by continuously pressurizing for 5 minutes or more. In addition, the temperature T is 50
Perform complete sterilization by repeating the continuous pressurization for 15 minutes or more or the pressurization for 1 minute and then returning to normal pressure for 30 seconds 5 times or more if the pressure P is set to 2000 ° C or more and the pressure P is 2000 kgf / cm ² or more. You can The pressure P is 40
If the pressure of 00 kgf / cm ^{2 is applied} for 3 minutes and then returned to normal pressure for 30 seconds 5 times or more, complete sterilization can be performed even at the temperature T = 20 ° C. at which the sterilization effect is lowest. That is, complete sterilization can be performed regardless of the temperature T.

As another example of the device, the liquid feed pump 21 is omitted from the high-pressure liquid sterilization device 1 ', and the up and down of the piston 4'inhales the unsterilized liquid to be treated 20 and pushes out the sterilized liquid to be treated. Some of the things I did.

For example, the valve 23 is closed and the valve 22 is opened with the tip of the piston 4'pushed into the vicinity of the lower end of the pressure vessel 2 '.

Thereafter, the piston 4'is extracted from the pressure vessel 2 ', so that the liquid 20 to be treated is supplied to the pressure vessel 2'through the conduit 24 of the piston 4'. When the pressure vessel 2'is filled with the liquid 20 to be treated, the valves 22 and 23 are both closed, and the piston 4'is driven to pressurize and sterilize the liquid 20 to be treated in the pressure container 2 '. To be done.

Subsequently, the pressurizing operation by the piston 4'is released and the valve 23
Open and push the piston 4'into the pressure vessel 2 ',
The liquid 20 to be treated after sterilization is discharged from the pressure vessel 2'through the valve 23 and the pipe line 25 to the outside of the apparatus. It is possible to sterilize the liquid to be treated 20 periodically and intermittently by repeating such a series of processes of supplying, pressurizing and discharging the liquid to be treated 20.

That is, with the valve 23 closed and the valve 22 open, the piston 4'is withdrawn in the pressure vessel 2 ', or the piston 4'is stationary and the valves 22 and 23 are both open. Each of the configurations for driving is an example of the liquid supply means according to the present invention.

Further, with the valve 23 of the conduit 25 opened, the piston 4'is pushed into the pressure vessel 2'and the liquid feed pump 21.
Each of the configurations for driving is an example of the liquid discharge means according to the present invention.

In the above embodiment, the liquid to be treated 20 is supplied to the pressure vessel 2'through the piston 4 ', but not limited to this, by connecting the pipe line 24 to the pressure vessel 2',
The liquid to be treated 20 may be directly supplied to the pressure vessel 2 '.

Further, for example, as still another device example, as in the continuous pressure sterilization device 31 shown in FIG. 7, the raw material tank 32 and the product tank 33 are connected via the high pressure pump 34, and the valve 22 shown in FIG. The high pressure pump 34 sucks and pressurizes the raw material from the raw material tank 32 by using the valve 35 corresponding to the above and the valve 36 corresponding to the valve 23, and repeatedly pushes the raw material into the product tank 33. The sterilization is continuously performed.

Further, as a modified example of this, as in the continuous pressure sterilizer 41 shown in FIG. 8, a valve 45 corresponding to the valve 22 of FIG.
49 and valves 46 and 50 corresponding to the valve 23 are used, and high-pressure pumps 44, 48, ... Are arranged so as to be substantially in series of two or more stages, and repeated pressurization is performed in each.
Those that increase the bactericidal effect are mentioned.

Then, the valve opening / closing of the valves 35, 36 and the like is controlled by a timer, and for example, the valve is repeatedly opened and closed a number of times during one cycle of valve opening / closing.

As can be understood from the above description, the present invention is a high-pressure liquid sterilizer for sterilizing a liquid to be treated under a high pressure condition,
A container for containing the liquid to be processed, a piston for pressurizing the liquid to be processed in the container, a liquid supply means for supplying the liquid to be processed to the container, and a pressurization / pressurization by the piston connected to the container. The present invention provides a high-pressure liquid sterilizer characterized by comprising a liquid discharge means for discharging the liquid to be treated after sterilization, according to which it is not necessary to raise the temperature of the liquid to be treated. Therefore, a high sterilization effect can be obtained without causing the quality deterioration of the liquid to be treated. Moreover, the high-pressure liquid sterilizer of the present invention is excellent in safety, operability, and economy.

[Brief description of drawings]

FIG. 1 is a structural explanatory view showing an example of a high-pressure liquid sterilizer according to an embodiment of the present invention, FIG. 2 is an external view of an example of an object to be treated, and FIG. 3 shows a relationship between pressure and survival rate of E. coli. The graph of the data shown, FIG. 4 is the graph of the data showing the relationship between the temperature and the survival rate of E. coli, FIG. 5 is the graph of the data showing the relationship between the pressurizing time and the survival rate of the E. coli, and FIG. The graph which shows the change of the survival rate in the case of pressurizing and intermittently pressurizing, FIG. 7 is a structural explanatory view of another example of the apparatus for carrying out the present invention, and FIG. FIG. 10 is a configuration explanatory view of still another example of the device for performing the above. (Explanation of symbols) 1 '... High-pressure liquid sterilizer 2' ... Pressure vessel 4 '... Piston 5 ... Hydraulic cylinder 11 ... Processing object 20 ... Processing liquid 21 ... Sending pumps 22,23 …… Valves 24, 25 …… Lines.

Claims (1)

[Claims] 1. A high-pressure liquid sterilizer for sterilizing a liquid to be treated under a high pressure condition, a container for containing the liquid to be treated, a piston for pressurizing the liquid to be treated in the container, and the liquid to be treated as described above. A high-pressure liquid sterilization apparatus comprising liquid supply means for supplying to a container and liquid discharge means connected to the container for discharging the liquid to be treated after being pressurized and sterilized by the piston.