【発明の詳細な説明】[Detailed description of the invention]
〔産業上の利用分野〕
本発明は病院等で使用する治療用器具類や食品
工場、製薬工場等で使用する器具類、容器類等あ
るいはこれらの工場で製造された製品等に付着す
る微生物類の滅菌を行う方法に関する。
〔従来の技術〕
従来、この種の滅菌方法としては被滅菌処理
物を収納した容器内に高圧蒸気を導入して滅菌す
る高圧蒸気滅菌法、被滅菌処理物をオーブン内
に収納し、大気圧雰囲気下にて加熱する乾熱滅菌
法、被滅菌処理物を収納した容器内に酸化エチ
レンを導入して加熱する化学的滅菌法等が知られ
ている。
〔発明が解決しようとする問題点〕
しかしながらの方法では一旦容器内を減圧に
した後、高圧蒸気を導入して処理し、次いで乾
燥、冷却を行う必要があり、処理を行うための装
置や処理操作が複雑となるとともに設備費も高
く、多くのエネルギーを要するために運転経費も
高くつくという欠点がある。またの方法では
200℃程度の高温で加熱する必要があり、このた
め被滅菌処理物の材質によつては被滅菌処理物が
焦げたり、発火する等、被滅菌処理物に変質をき
たす虞れがあつた。更にの方法に用いる酸化エ
チレンは猛毒であり、爆発性があり、処理作業に
危険を伴うとともに、滅菌処理終了までに１日程
度かかり、また被滅菌処理物に残留した酸化エチ
レンの除去を含め処理時間が長く効率的でないと
いう問題があつた。
〔問題点を解決するための手段〕
本発明は上記の点に鑑みなされたもので、上記
従来技術を欠点を解決した滅菌方法を提供するこ
とを目的とする。
即ち本発明は耐圧容器内に被滅菌処理物を収納
して耐圧容器内を大気圧以上の圧力とし且つ
1atm以上の分圧の酸素が存在する条件下で加熱
することを特徴とする滅菌方法を要旨とするもの
である。
本発明において酸素の存在下とは容器内に酸素
のみが充填されている場合、空気が充填されてい
る場合、酸素と他の気体（通常窒素、ヘリウム等
の不活性気体が用いられるが、窒素が一般的であ
る。）の混合物が充填されている場合が挙げられ
る。また加圧は酸素分圧が1atm以上となるよう
に行う。従つて酸素のみによつて加圧する場合は
大気圧と等しい圧力以上（即ち無加圧の場合も含
む）であり、空気を用いる場合には約5atm以上
の圧力に加圧する。尚、加圧は特に酸素の分圧が
1atm以上、11atm以下となるように行うことが
好ましい。加熱温度は50〜200℃、特に60〜140℃
が好ましい。また加熱時間は被滅菌処理物の種類
や汚染状態によつても異なるが、通常40〜80分で
あり、平均して60分程度である。
〔実施例〕
以下、本発明の一実施例を図面に基き説明す
る。
本発明方法の実施には例えば、第１図に示す如
き装置が用いられる。この装置は断熱材１を内張
りした耐圧容器２を有し、被滅菌処理物３は耐圧
容器２内の金網４上に載置されて耐圧容器２内に
収納される。耐圧容器２は蓋５によつて開放及び
密閉が可能に構成されている。６は耐圧容器２内
に酸素、空気等の送り込み及び排出を行う送排気
弁、７は圧力計、８は温度センサー、９はヒータ
ーである。また１０は安全弁で万一過大な圧力が
加わつたり、火災等による異常圧力上昇が生じる
と、安全弁１０が開いて耐圧容器２内の過剰圧力
が排出され、耐圧容器２の破裂事故を未然に防止
し得るように構成されている。上記装置では被滅
菌処理物３を収納した後、蓋５によつて耐圧容器
２を密閉し、送排気弁６より酸素、空気等を送り
込んで耐圧容器内を所定圧力とするとともに、ヒ
ーター９によつて所定の温度に加熱して処理する
が、耐圧容器内温度は温度センサー８によつて検
出され、この温度データに基いて図示しない制御
装置がヒーター９への通電量を制御して耐圧容器
内が所定の温度に保持され、以て被滅菌処理物３
の滅菌処理が行われる。
以下に具体的実施例を挙げて本発明を更に詳細
に説明する。
実施例１〜２、比較例１
指標菌に指定されている加熱に対して最も抵抗
力の強い芽胞形成菌（Bacillus
stearothermophilus）の芽胞（芽胞量104個）を
ろ紙に付着させた試料を、第１図に示す装置の耐
圧容器内に収納し、耐圧容器内圧を空気によつて
第１表に示す圧力に保持して130℃に加熱処理し
た。処理後の試料を所定の培養液中に浸漬し、55
℃で１週間培養を行つた時の培養液の汚濁の有無
で滅菌処理において有効に滅菌されているか否か
を判定し、有効処理時間と無効処理時間を求め
た。結果を第１表にあわせて示す。尚、第１表の
圧力の項の括弧内は酸素分圧（単位はatm）を示
す。
[Industrial Application Field] The present invention is directed to treatment of microorganisms that adhere to therapeutic instruments used in hospitals, instruments, containers, etc. used in food factories, pharmaceutical factories, etc., and products manufactured in these factories. sterilization method. [Prior Art] Conventionally, this type of sterilization method includes the high-pressure steam sterilization method, in which high-pressure steam is introduced into a container containing the object to be sterilized, and the method in which the object to be sterilized is stored in an oven and exposed to atmospheric pressure. A dry heat sterilization method in which the object is heated in an atmosphere, a chemical sterilization method in which ethylene oxide is introduced into a container containing an object to be sterilized and heated, and the like are known. [Problems to be solved by the invention] However, in this method, it is necessary to first reduce the pressure inside the container, then introduce high-pressure steam for treatment, and then dry and cool it. The disadvantages are that the operation is complicated, the equipment cost is high, and the operation cost is high because it requires a lot of energy. In another way
It is necessary to heat the object at a high temperature of about 200°C, and therefore, depending on the material of the object to be sterilized, there is a risk that the object to be sterilized may be scorched or ignited, resulting in deterioration of the quality of the object to be sterilized. Furthermore, the ethylene oxide used in this method is highly poisonous and explosive, making the treatment process dangerous, and it takes about a day to complete the sterilization process. The problem was that it took a long time and was not efficient. [Means for Solving the Problems] The present invention has been made in view of the above points, and it is an object of the present invention to provide a sterilization method that overcomes the drawbacks of the above-mentioned prior art. That is, the present invention stores objects to be sterilized in a pressure-resistant container, and makes the pressure inside the pressure-resistant container higher than atmospheric pressure.
The gist of this is a sterilization method characterized by heating under conditions where oxygen is present at a partial pressure of 1 atm or more. In the present invention, the presence of oxygen means that the container is filled only with oxygen, or is filled with air, or contains oxygen and other gases (usually an inert gas such as nitrogen or helium is used, but nitrogen ) is commonly used. Further, pressurization is performed so that the oxygen partial pressure becomes 1 atm or more. Therefore, when pressurizing with oxygen alone, the pressure is equal to or higher than atmospheric pressure (that is, including the case of no pressurization), and when using air, the pressure is pressurized to about 5 atm or higher. In addition, when pressurizing, especially the partial pressure of oxygen
It is preferable to set the temperature to 1 atm or more and 11 atm or less. Heating temperature is 50-200℃, especially 60-140℃
is preferred. Although the heating time varies depending on the type of object to be sterilized and the state of contamination, it is usually 40 to 80 minutes, with an average of about 60 minutes. [Example] Hereinafter, an example of the present invention will be described based on the drawings. For example, an apparatus as shown in FIG. 1 is used to carry out the method of the present invention. This apparatus has a pressure container 2 lined with a heat insulating material 1, and the object to be sterilized 3 is placed on a wire gauze 4 inside the pressure container 2 and housed in the pressure container 2. The pressure container 2 is configured to be openable and airtight with a lid 5. 6 is a supply/exhaust valve for supplying and discharging oxygen, air, etc. into the pressure-resistant container 2, 7 is a pressure gauge, 8 is a temperature sensor, and 9 is a heater. In addition, 10 is a safety valve that, in the unlikely event that excessive pressure is applied or an abnormal pressure rise occurs due to a fire, etc., the safety valve 10 opens and the excess pressure inside the pressure vessel 2 is discharged, thereby preventing a rupture accident of the pressure vessel 2. It is designed to prevent In the above device, after storing the object to be sterilized 3, the pressure container 2 is sealed with the lid 5, and oxygen, air, etc. are sent in from the supply/exhaust valve 6 to bring the inside of the pressure container to a predetermined pressure. Therefore, the pressure-resistant container is heated to a predetermined temperature for processing.The temperature inside the pressure-resistant container is detected by a temperature sensor 8, and based on this temperature data, a control device (not shown) controls the amount of electricity supplied to the heater 9, and the pressure-resistant container is heated to a predetermined temperature. The interior is maintained at a predetermined temperature, and the object to be sterilized 3
sterilization process is performed. The present invention will be explained in more detail by giving specific examples below. Examples 1-2, Comparative Example 1 Spore-forming bacteria (Bacillus
A sample containing spores (10 4 spores) of A. stearothermophilus adhered to a filter paper was stored in a pressure-resistant container of the apparatus shown in Figure 1, and the internal pressure of the pressure-resistant container was maintained at the pressure shown in Table 1 with air. and heat-treated at 130°C. After treatment, the sample was immersed in the specified culture solution and incubated for 55 minutes.
It was determined whether or not the sterilization was effectively performed based on the presence or absence of contamination of the culture solution after culturing at 1 week at ℃, and the effective treatment time and ineffective treatment time were determined. The results are also shown in Table 1. Note that the value in parentheses in the pressure section of Table 1 indicates the oxygen partial pressure (unit: atm).
【表】
実施例３〜４、比較例２
耐圧容器内に第２表に示すガスにて、それぞれ
10Kg／cm2・Ｇに加圧して130℃で加熱した他は上
記実施例１〜２及び比較例１と同様にして滅菌処
理を行い、有効処理時間、無効処理時間を求め
た。結果を第２表にあわせて示す。尚、実施例３
における酸素分圧は11atm、実施例４における酸
素分圧は2.2atm、比較例２における酸素分圧は
0atmである。[Table] Examples 3 to 4, Comparative Example 2 Each was placed in a pressure container with the gas shown in Table 2.
Sterilization was performed in the same manner as in Examples 1 to 2 and Comparative Example 1, except that the samples were pressurized to 10 kg/cm 2 ·G and heated at 130° C., and the effective processing time and ineffective processing time were determined. The results are also shown in Table 2. Furthermore, Example 3
The oxygen partial pressure in Example 4 was 2.2 atm, and the oxygen partial pressure in Comparative Example 2 was 11 atm.
It is 0 atm.
〔発明の効果〕〔Effect of the invention〕
以上説明したように、本発明方法は被滅菌処理
物を密閉容器内に収納して該容器内を大気圧以上
の圧力とし且つ1atm以上の分圧の酸素が存在す
る条件下で加熱する方法を採用したことにより、
従来の高圧蒸発滅菌法に比べて短時間で滅菌処理
が行なえるとともに、滅菌処理に用いる装置の操
作や保守が簡単でしかも運転経費が安くすみ、本
発明の実施に用いる耐圧容器は構造が単純なため
製造や保守が容易である。また本発明方法は、酸
化エチレンを用いる化学滅菌法のように爆発や中
毒の虞れがない。更に本発明方法では大気圧を越
える圧力で加圧して加熱した場合には耐圧容器内
に乱流が生じるとともに、熱伝導度も大きくなり
被滅菌処理物の温度を短時間で均一に昇温して加
熱処理できる。しかも微生物体の一部を構成する
不飽和油脂は高酸素分圧下では常圧の空気中より
も低温で熱酸化分解されるため、特に1atm以上
の分圧を有する酸素の存在下に加熱するときわめ
て滅菌効果が高く、例えば空気で10Kg／cm2・Ｇに
加圧した場合（絶対圧で11atmであり、酸素分圧
は2.2atm）、130℃で60分程度の加熱ですみ、こ
の程度の温度、時間の加熱では微生物体を構成す
る不飽和油脂は熱酸化分解されても通常の有機物
は変質したり発火したりすることがないから、従
来の乾熱滅菌法のように被滅菌処理物に変質をき
たすことなく、滅菌処理を行い得る等の効果を有
する。
As explained above, the method of the present invention involves storing the object to be sterilized in a closed container and heating the container under conditions where the pressure in the container is higher than atmospheric pressure and oxygen with a partial pressure of 1 atm or higher is present. By adopting
In addition to being able to perform sterilization in a shorter time than conventional high-pressure evaporation sterilization methods, the equipment used for sterilization is easy to operate and maintain, and operating costs are low, and the pressure-resistant container used in the practice of the present invention has a simple structure. Therefore, manufacturing and maintenance are easy. Furthermore, the method of the present invention does not pose the risk of explosion or poisoning, unlike chemical sterilization methods using ethylene oxide. Furthermore, in the method of the present invention, when heating is performed under pressure exceeding atmospheric pressure, turbulent flow occurs inside the pressure-resistant container, and the thermal conductivity also increases, making it possible to uniformly raise the temperature of the object to be sterilized in a short time. Can be heat treated. Moreover, unsaturated fats and oils that constitute part of microorganisms are thermally oxidized and decomposed at a lower temperature under high oxygen partial pressure than in air at normal pressure, so heating in the presence of oxygen with a partial pressure of 1 atm or higher is extremely difficult. It has a high sterilization effect; for example, when pressurized with air to 10Kg/cm 2 G (absolute pressure is 11atm, oxygen partial pressure is 2.2atm), heating at 130℃ is only required for about 60 minutes, and the temperature is around this level. Even though the unsaturated fats and oils that make up microorganisms are thermally oxidized and decomposed by heating for a long time, ordinary organic substances do not change in quality or catch fire, so it is not possible to It has the advantage of being able to be sterilized without causing deterioration.
【図面の簡単な説明】[Brief explanation of drawings]
図面は本発明の一実施例を示し、第１図は本発
明方法の実施に用いる装置の縦断面略図である。
２……耐圧容器、３……被滅菌処理物、６……
送排気弁、９……ヒーター。
The drawings show an embodiment of the invention, and FIG. 1 is a schematic longitudinal cross-sectional view of an apparatus used for carrying out the method of the invention. 2... Pressure-resistant container, 3... Item to be sterilized, 6...
Supply/exhaust valve, 9...Heater.