JP3969150B2 - Disinfection method of processed material - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for disinfecting an object to be processed , and more particularly to a method for disinfecting an object to be processed using steam .
[0002]
[Prior art and its problems]
Various articles used in fields such as food processing, cooking, and medical care, such as cooking utensils and medical utensils, need to ensure contamination by removing contamination from bacteria. For this reason, as a method of disinfecting such an article, a method of treating the article in a steam atmosphere has been proposed (see, for example, Japanese Patent Laid-Open No. 9-173425). In this disinfection method, after placing an article in an airtight container, the airtight container is filled with high-temperature steam. Thereby, the article | item arrange | positioned in an airtight container is exposed to high temperature vapor | steam, and is sterilized.
[0003]
By the way, there are various types of bacteria that contaminate articles, and some of them have high heat resistance. Therefore, when disinfecting an article by the method described above, in order to increase the reliability of the disinfection effect in consideration of the attachment of highly heat-resistant bacteria, the steam temperature is usually set higher. It is necessary to set a longer treatment time with steam. For this reason, the disinfection method described above increases the cost of energy and equipment, and requires a long processing time.
[0004]
An object of the present invention is to effectively disinfect an object to be processed with steam in a short time.
[0005]
[Means for Solving the Problems]
The method for disinfecting an object to be processed according to the present invention includes a step of disposing an object to be processed inside an airtight container, and an agent for adjusting pH into the airtight container in which the object to be processed is disposed . And a step of filling in a pressurized state saturated steam whose pH is adjusted to the alkaline side by addition. According to such a disinfection method, hydrolysis of hydrolyzable substances such as bacteria and endotoxin adhering to the object to be treated is promoted, and the disinfection time of the object to be treated by steam can be shortened.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
With reference to FIG. 1, the steam processing apparatus for implementing the disinfection method which concerns on one Embodiment of this invention is demonstrated. In the figure, a steam processing apparatus 1 is for disinfecting an object to be processed, which will be described later, using steam, and includes an airtight container 2, a steam supply unit 3, an air supply unit 4, an exhaust unit 5, and a control unit 6. Mainly prepared.
[0010]
The airtight container 2 mainly includes a container body 20 and a jacket 21. The container body 20 has a pressure door (not shown) for taking in and out an object to be processed, which will be described later, and the inside can be set airtight with the pressure door closed. The container body 20 is a pressure vessel having a pressure resistance of at least 0.3 MPa, preferably 0.3 to 1.0 MPa, usually formed in a rectangular box shape or a cylindrical shape. The container body 20 further includes a temperature sensor 25 for detecting the internal temperature and a pressure sensor 26 for detecting the internal pressure.
[0011]
On the other hand, the jacket 21 is disposed so as to surround the outside of the container body 20 so that a space 22 is formed between the jacket 21 and the container body 20. A first drain path 23 extends from the jacket 21. The first drain path 23 has a steam trap 24 and a check valve 23 a in this order, and communicates with the end of the exhaust part 5.
[0012]
The steam supply unit 3 mainly includes a steam generator 30 and a steam supply path 31 for supplying the steam generated by the steam generator 30 to the airtight container 2. The steam generator 30 is, for example, a boiler device that generates steam by heating water, and mainly includes a boiler body 30a and a water supply path 30b for supplying water serving as a steam source to the boiler 30a. is doing.
[0013]
The steam supply path 31 extends from the boiler body 30a and communicates with the jacket 21 of the airtight container 2, and in order from the boiler body 30a side, a first steam control valve 32 for controlling the flow of steam, and the boiler body It has a steam pressure adjusting valve 33 for adjusting the pressure of steam (saturated steam) supplied from 30a, and a chemical addition device 36. Here, the medicine addition device 36 is for supplying a medicine for adjusting the pH of the steam into the steam moving toward the hermetic container 2 in the steam supply path 31, and stores the medicine. And a chemical injection pump 38 for supplying the chemical in the chemical tank 37 into the vapor supply path 31. The chemical used here is for adjusting the pH of the vapor to the alkaline side (that is, for adjusting the pH of the vapor to be higher than 7), and is usually liquid or aqueous solution and volatile. belongs to. Specifically, ammonia , morpholine, methylamine and the like can be exemplified.
[0014]
Further, the steam supply path 31 has a branch steam path 34 that branches from between the drug addition device 36 and the jacket 21. This branched steam path 34 communicates with the upper part of the container body 20 and has a second steam control valve 35 for controlling the flow of steam.
[0015]
The air supply unit 4 includes an air supply path 40 that communicates with the container body 20, and the air supply path 40 includes a check valve 41, an air supply valve 42, and an air filter 43 in order from the container body 20 side. ing. The air filter 43 is for cleaning the outside air and taking it into the air supply path 40.
[0016]
The exhaust part 5 is a pipe extending from the lower part of the container body 20 and branches into three lines, a second drain path 50, a discharge path 51, and a decompression path 52. The second drain path 50 has a steam trap 50a, a check valve 50b, and a water sampling device 50c in this order. The water sampling device 50c is for collecting a part of the condensed water from the container body 20 discharged through the second drain path 50. The discharge path 51 has an exhaust valve 51a and a check valve 51b in this order. Further, the decompression path 52 includes a decompression control valve 53 and a vacuum pump 54 in order from the container body 20 side. Further, check valves 52a and 52a are provided on both sides of the vacuum pump 54, respectively. Note that the ends of the second drain path 50, the discharge path 51, and the decompression path 52 are gathered together with the first drain path 23 to form a single exhaust / drainage path 55.
[0017]
The control device 6 is for controlling the operation of the steam treatment device 1, and based on the temperature information from the temperature sensor 25 and the pressure information from the pressure sensor 26, the valves 32 and 33 are set according to a preset procedure. , 35, 42, 51a, 53, the operation of the medicine injection pump 38 and the vacuum pump 54 are set to be controllable. In addition, the control method in the control apparatus 6 is not specifically limited, Electronic control using a microcomputer may be sufficient, and relay control and sequence control may be sufficient.
[0018]
Next, a method for disinfecting an object to be processed using the above-described steam processing apparatus 1 will be described. In the following description, each valve constituting the steam treatment apparatus 1 is basically closed unless otherwise specified.
[0019]
First, in the airtight container 2, the pressure-resistant door of the container main body 20 is opened, and an object to be processed is placed in the container main body 20. Here, the object to be treated that can be sterilized using the steam treatment apparatus 1 is particularly limited as long as it is a solid that has moisture resistance, heat resistance, and pressure resistance and does not denature under a high temperature and high humidity environment. is not. Examples of such solid materials include injection needles, syringes, blood transfusion sets, infusion sets, artificial heart valves, blood circuits for cardiopulmonary bypass, gauze and other fabrics and surgical instruments, medical instruments, chemical and biological Examples thereof include pipes such as laboratory instruments, cooking utensils, tableware, and medical equipment, and membranes such as reverse osmosis membranes and ultrafiltration membranes. In addition, such a to-be-processed object normally provides the net-like shelf which can let vapor | steam pass in the container main body 20, and arrange | positions on the said shelf.
[0020]
Next, after the pressure-resistant door is closed and the container body 20 is set in an airtight state, a preheating process for the object to be processed is performed. Here, in the steam supply unit 3, the first steam control valve 32 is opened, and high-temperature saturated steam from the steam generator 30 is supplied into the jacket 21 through the steam supply path 31. As a result, the jacket 21, that is, the space 22 is filled with high-temperature steam, and the container body 20 is warmed from the outside. Thereby, the to-be-processed object arrange | positioned in the container main body 20 is heated by the radiant heat from the wall surface of the container main body 20. FIG.
[0021]
Next, a treatment process using steam is performed on the workpiece. Hereinafter, the subsequent processing operation will be described with reference to FIG. FIG. 2 is an explanatory diagram showing the relationship between the elapsed time and the pressure in the container body 20. In the subsequent processing operation, it is preferable to maintain the first steam control valve 32 in an open state and maintain the supply of steam into the jacket 21. If it does in this way, the preheating state of the to-be-processed object in the container main body 20 can be maintained favorable.
[0022]
First, the air in the container main body 20 is excluded in the state where the preheated object to be processed is disposed (air exclusion process). Here, the exhaust valve 51a is closed, the vacuum pump 54 is operated, and the decompression control valve 53 is opened. Thereby, the air in the container main body 20 is sucked through the pressure reducing path 52, and the inside of the container main body 20 is gradually depressurized to a pressure lower than the atmospheric pressure as indicated by A in FIG. 2 (decompression step).
[0023]
Next, the decompression control valve 53 is closed, the exhaust valve 51a is opened, and the second steam control valve 35 is opened. Thereby, a part of the saturated steam from the steam generator 30 flows from the steam supply path 31 to the branch steam path 34 and is continuously supplied into the container body 20. As a result, the container body 20 is gradually filled with steam, and as shown by B in FIG. 2, the steam gradually rises to a state where the internal pressure is slightly higher than atmospheric pressure. At this time, the vapor supplied into the container main body 20 expands in the container main body 20 in a decompressed state to decrease the specific gravity, and discharges air having a relatively large specific gravity remaining in the container main body 20. It is discharged outside through the discharge path 51 while being pushed into the path 51. That is, the steam from the branch steam path 34 passes through the container body 20 while pushing out the air remaining in the container body 20 (steam passage process).
[0024]
Next, while maintaining the supply of saturated steam from the branch steam path 34, the pressure in the container body 20 is maintained to be substantially constant, and then the exhaust valve 51 a is closed. Thereby, as shown by C in FIG. 2, the pressure in the container main body 20 quickly rises due to the continuously supplied saturated steam. That is, the container body 20 is filled with steam in a pressurized state (filling step). Then, after the pressure in the container body 20 reaches a predetermined pressure, the exhaust valve 51a is opened. Thereby, the vapor | steam filled in the container main body 20 is discharged | emitted outside through the discharge path 51, As a result, as shown by D in FIG. 2, the pressure in the container main body 20 falls rapidly to atmospheric pressure (discharge | emission). Process). At this time, the air remaining in the container body 20 is discharged into the discharge path 51 together with the discharged steam, and is effectively removed following the above-described steam passing step. In particular, in this discharge step, the object to be processed disposed in the container body 20, particularly the object to be processed having a narrow and narrow part such as a syringe barrel or a needle, or air permeability such as gauze. A very small amount of air remaining or adhering to the inside or inside of the object to be processed is effectively discharged together with the vapor.
[0025]
In addition, the above-mentioned filling process and discharge | emission process may be repeatedly performed in this order 2 cycles or more as shown by E in FIG. 2 as needed. When the filling step and the discharging step are repeated in this manner, the air remaining in the container body 20, particularly the air adhering to the object to be processed can be more effectively eliminated.
[0026]
Moreover, you may make it maintain the pressurization state with which the vapor | steam was filled in the container main body 20 for a predetermined period before shifting to a discharge process from a filling process. If it does in this way, when the to-be-processed object is cloths, such as gauze, the air which remains in the inside can be excluded more effectively.
[0027]
During the discharge process as described above, the medicine pump 38 is operated to continuously add the medicine in the medicine tank 37 to the steam moving in the steam supply path 31. The added drug vaporizes rapidly and is mixed with the vapor. As a result, the pH of the vapor is adjusted to the alkaline side by the added drug. Here, the pH of the vapor after adjustment is usually preferably set to 9 or more, and more preferably set to 11 or more.
[0028]
The pH of the steam can be confirmed by collecting condensed water from the container body 20 using the water sampling device 50c of the second drain path 50 and measuring the pH of this condensed water.
[0029]
Next, the exhaust valve 51a is closed after the pressure in the container body 20 is reduced to atmospheric pressure by the above-described discharge process. As a result, the container body 20 is filled with high-temperature saturated steam whose pH is adjusted as described above, and the pressure in the container body 20 is gradually increased by the saturated steam as indicated by F in FIG. . As a result, the container body 20 is filled with hot saturated steam whose pH is adjusted to the alkaline side in a pressurized state. Here, the saturated vapor filled in the container main body 20 is deprived of latent heat on the surface of the object to be processed and condenses. Thereby, the surface of a to-be-processed object is coat | covered with the condensed water of the same pH as the pH of saturated steam. Since the saturated steam is continuously supplied into the container body 20, the temperature of the condensed water is balanced with the temperature of the saturated steam. In addition, since the object to be processed is preheated in the above-described preheating step, it is heated by the saturated steam and quickly equilibrates with the temperature of the saturated steam.
[0030]
As described above, the object to be treated is coated with condensed water having the same pH and temperature as those of saturated steam, and the surface is treated with such condensed water (steam treatment step). When such a state is maintained for a predetermined time indicated by f in FIG. 2, hydrolyzable substances adhering to the object to be treated, for example, proteins such as bacteria and lipopolysaccharide (LPS) such as endotoxin Hydrolysis is promoted because of saturated steam and condensed water with the same pH and temperature. Therefore, the object to be treated is sterilized in a short time and the endotoxin activity is reduced as compared with the case of treating with neutral steam having a pH of 7. Alternatively, the object to be treated can be treated with a lower temperature saturated steam when the treatment time is set in the same manner as when treating with neutral steam having a pH of 7. Therefore, in this case, the energy cost for obtaining saturated steam and the cost of equipment can be suppressed.
[0031]
In addition, in the steam treatment process as described above, since the air in the container main body 20 is effectively removed by the above-described steam passage process, the filling process and the discharge process are particularly performed. In this case, since the air adhering to it is removed more effectively, the whole is exposed to high-temperature saturated steam whose pH is uniformly adjusted without being affected by the air. For this reason, since the whole surface of the object to be treated is uniformly coated with condensed water, the whole is effectively sterilized without unevenness, and the entire endotoxin activity is reduced without unevenness.
[0032]
In the steam treatment process described above, the treatment temperature of the object to be treated, that is, the temperature of the saturated steam, varies depending on the main treatment purpose, that is, whether the main purpose is sterilization or reduction of endotoxin activity. However, it is usually preferable to set the temperature at 120 ° C. or higher. More specifically, it is usually preferably set to 120 to 190 ° C, more preferably set to 135 to 160 ° C. When the said temperature is less than 120 degreeC, it may become difficult to achieve effectively sterilization of a to-be-processed object and reduction of endotoxin activity in a short time. The upper limit of the processing temperature of the object to be processed is not particularly limited. Usually, however, the temperature of the object to be processed is regulated to a temperature at which the object to be processed is not damaged or deteriorated according to the type or material of the object to be processed. Is preferred. Further, as the processing temperature increases, the pressure resistance of the container body 20 needs to be increased, and the airtight container 2 becomes expensive. Therefore, the upper limit of the processing temperature is regulated in consideration of the economics of the airtight container 2. preferable.
[0033]
Incidentally, when sterilizing an object to be processed using steam having a pH of 7 or reducing the endotoxin activity of the object to be processed, the temperature of the saturated steam usually needs to be set higher than the above temperature. In the disinfection method according to the embodiment, the processing temperature (saturated steam temperature) for sterilization and reduction of endotoxin activity can be set lower as described above, and the energy cost required for processing the object to be processed is reduced. can do.
[0034]
In the steam treatment step, the pressure in the container body 20 is usually preferably set to 0.1 MPa or more. More specifically, it is usually preferably set to 0.1 to 1.0 MPa, and more preferably set to 0.3 to 0.6 MPa. When this pressure is less than 0.1 MPa, it may be difficult to sterilize the object to be processed in a short time or to reduce the endotoxin activity of the object to be processed. Incidentally, although the upper limit of the pressure in the container main body 20 is not particularly limited, it is generally regulated by the pressure resistance of the container main body 20 and the object to be processed.
[0035]
After the elapse of the above processing time, the second steam control valve 35 is closed to stop the supply of saturated steam to the container body 20, and at the same time, the exhaust valve 51a is set to an open state. Thereby, the vapor | steam filled in the container main body 20 is exhausted outside through the exhaust path 51, and the pressure in the container main body 20 falls to atmospheric pressure.
[0036]
After the pressure in the container body 20 is reduced to atmospheric pressure, a drying process is subsequently performed. Here, first, the exhaust valve 51a is closed, and the vacuum control valve 53 is set to an open state while the vacuum pump 54 is operated. Thereby, the pressure in the container main body 20 falls below atmospheric pressure, as shown to G of FIG. When this state is maintained for a predetermined time, the inside of the container body 20 and the object to be processed are cooled and vacuum dried.
[0037]
Next, the vacuum control valve 53 is closed while the vacuum pump 54 is operated, and the air supply valve 42 is opened. As a result, clean air from the air filter 43 is introduced into the container body 20 through the air supply path 40, and the internal pressure rises as indicated by H in FIG. When the pressure in the container body 20 reaches a predetermined pressure equal to or lower than the atmospheric pressure, the air supply valve 42 is closed and the pressure reduction control valve 53 is opened again. Thereby, the pressure in the container main body 20 falls again as shown in I of FIG. When the internal pressure of the container main body 20 is changed in the range below the atmospheric pressure in this way (pressure changing step), the object to be processed in the container main body 20 is cooled more effectively and dried. . In general, such a pressure fluctuation process is preferably repeated two or more cycles as shown in J of FIG.
[0038]
Next, the pressure reducing control valve 53 is closed, the vacuum pump 54 is stopped, and the air supply valve 42 and the exhaust valve 51a are opened. Thereby, the inside of the container main body 20 returns to atmospheric pressure (K in FIG. 2), and clean air from the air filter 43 continuously passes through the air supply path 40 in the container main body 20. As a result, the workpiece is dried by the passing air. At this time, the pressure in the container body 20 is preferably maintained at atmospheric pressure as indicated by L in FIG.
[0039]
After completion of the series of steps as described above, the first steam control valve 32 is closed and the supply of steam into the jacket 21 is stopped. Moreover, the to-be-processed object after a process can be taken out if the pressure | voltage resistant door of the container main body 20 is opened.
[0040]
As described above, in the disinfection method according to this embodiment, the object to be treated is treated with the high-temperature saturated steam whose pH is adjusted to the alkaline side. Therefore, the object to be treated is subjected to dry heat treatment or neutral saturated steam. Compared with the case of processing with, the processing object can be sterilized in a relatively short time, or the endotoxin activity of the processing object can be reduced.
[0043]
[Experimental example]
Experimental example 1
A metal medical device was treated under steam having a pH of 12 and a temperature of 121 ° C., and a change in endotoxin amount was measured by a Limulus test. The results are shown in FIG.
[0044]
Experimental example 2
A metallic medical device was treated under steam having a pH of 7 and a temperature of 121 ° C., and a change in endotoxin amount was measured by a Limulus test. The results are shown in FIG.
[0045]
Experimental example 3
A metal medical device was treated under steam having a pH of 7 and a temperature of 175 ° C., and a change in endotoxin amount was measured by a Limulus test. The results are shown in FIG.
[0046]
If the comparison result of the evaluation experiment example 1 and the results of Experimental Example 2 and 3, is adjusted for pH of steam 12, as compared with the case of neutral (pH 7), for reducing the endotoxin amount Processing time is greatly reduced. In order to obtain the same effect with steam at pH 7, a temperature condition of 175 ° C. or higher is required. When processing under a temperature condition of 175 ° C. or higher, the pressure vessel is expensive because it needs to have a pressure resistance of at least 1.0 MPa, but in the case of Experimental Example 1 , it is necessary to use such an expensive pressure vessel. This is advantageous from the viewpoint of economy.
[0047]
Further, according to Experimental Example 1 , it can be expected that even when the saturated steam temperature is low, the endotoxin amount of the object to be treated can be effectively reduced in a short time by further increasing the pH.
[0048]
【The invention's effect】
In the disinfection method of the present invention, since the saturated vapor whose pH is adjusted to the alkaline side is filled in an airtight container in which the object to be processed is placed in a pressurized state, the disinfection time of the object to be processed is reduced. It can be shortened.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a steam treatment apparatus for performing a disinfection method according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram showing the relationship between the elapsed time and the pressure in the container body during the execution of the disinfection method according to the embodiment of the present invention using the steam processing apparatus.
FIG. 3 is a graph showing the results of Experimental Example 1, Experimental Example 2, and Experimental Example 3 .
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Steam processing apparatus 2 Airtight container 3 Steam supply part 30 Steam generator 30b Water supply path 31 Steam supply path 36 Drug addition apparatus

Claims (1)

Placing the object to be processed inside an airtight container; and
Filling a saturated vapor whose pH is adjusted to the alkaline side by addition of a chemical for adjusting the pH into the airtight container in which the object is disposed;
Disinfection method for objects to be treated.

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