JPH0889563A - Sterilizing method - Google Patents

Abstract

PURPOSE: To provide a sterilizing method capable of not only sterilizing microorganisms which do not form spores but sterilizing the spores which are formed with sporulation bacteria. CONSTITUTION: Sterilizing water having pH of <=4.0 at room temp., oxidation reduction potential of >=820mV, dissolved chlorine concn. of 1 to 200ppm and dissolved oxygen concn. of <=50ppm and an object to be sterilized are brought into contact with each other at >=40 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for sterilizing microorganisms, and more particularly to a method for enhancing the sterilizing action of conventionally known sterilizing water for use.

[0002]

As sterilizing water for sterilizing microorganisms,
Various things are known conventionally. For example, JP-A-1
-180293 discloses sterilized water by electrolysis of water, and JP-A-2-111708 describes sterilized water by electrolysis of saline. These sterilizing waters are used for sterilizing various objects to be sterilized such as food materials, tableware, cookers, and hand towels.

[0003]

However, in the conventional sterilization method, since the sterilizing water as described above is directly brought into contact with the object to be sterilized, that is, the sterilizing water in the room temperature state and the sterilizing water in the room temperature state are sterilized. Since the sterilization treatment is performed by contacting the target object, it is used for sterilization of microorganisms such as general bacteria that do not form spores, Escherichia coli, Staphylococcus, and MRSA (methicillin-resistant Staphylococcus aureus), which is a problem in nosocomial infections. Was effective, but had little effect on spores formed by spore-forming bacteria (spore-forming bacteria).

Therefore, an object of the present invention is to provide not only the sterilization of microorganisms which do not form spores but also the sterilization method which can sterilize the spores formed by spore-forming bacteria.

[0005]

In order to achieve the above object, the sterilization method of the present invention has, as a first constitution, a room temperature, a pH of 4.0 or less, a redox potential of 820 mV or more, and a dissolved chlorine concentration. Of 1 to 200 ppm and a dissolved oxygen concentration of 50 ppm or less and sterilized water and an object to be sterilized at a temperature of 40
The feature is that they are contacted at ℃ or more.

In the second structure of the present invention, after the temperature of the object to be sterilized is raised to 60 ° C. or higher, the pH is 4.
It is characterized in that it is brought into contact with sterilized water of 0 or less, an oxidation-reduction potential of 820 mV or more, a dissolved chlorine concentration of 1 to 200 ppm, and a dissolved oxygen concentration of 50 ppm or less at room temperature or higher.

Furthermore, in a particularly preferred embodiment of the present invention, the sterilized water has a pH of 3.0 or less at room temperature, an oxidation-reduction potential of 1000 mV or more, and a dissolved chlorine concentration of 5 to 200.
ppm, the dissolved oxygen concentration is 10 to 50 ppm, and the contact temperature between the sterilizing water and the object to be sterilized or the temperature rise temperature of the object to be sterilized is 80 ° C. or higher.

The room temperature in the present invention is about 25.
Means ° C. The redox potential is the potential of the noble metal electrode with respect to the silver / silver chloride electrode in sterilized water.

As described above, the sterilizing effect of the sterilizing water is increased by increasing the temperature of either or both of the sterilizing water and the object to be sterilized to a predetermined temperature and performing the sterilizing treatment. Can be greatly increased. This is a finding obtained as a result of various investigations by the present inventors.

In the first structure of the present invention, sterilized water having a predetermined pH, redox potential, dissolved chlorine concentration, and dissolved oxygen concentration at room temperature, that is, sterilized water having predetermined physical property values at room temperature. After producing, the temperature is raised to a predetermined temperature and used, but in this case, when the temperature of the sterilizing water is increased, the dissolved chlorine and the like are continuously decreased by this, and the sterilizing action is reduced. It is desirable to use it soon after the temperature is raised.

[0011]

Embodiments of the present invention will be described below. Example 1 A bacterial solution at room temperature was added to sterilized water kept at various temperatures,
The bactericidal effects due to the difference in temperature of the sterilized water were compared.

As the bacterial solution, Bacillus subtilis (Bac
illus subtilis), and the sterilizing water used was that obtained by electrolysis of saline. Specifically, a container partitioned by an ion exchange membrane is filled with tap water containing a small amount of salt, a cathode and an anode are arranged with the ion exchange membrane sandwiched therebetween, a voltage is applied, and the anode is electrolyzed. The liquid overflowed on the side was used as sterilizing water. The physical properties of this sterilized water were pH = 2.2, redox potential of 1150 mV, dissolved chlorine concentration of 16 ppm, and dissolved oxygen concentration of 25 ppm. The redox potential was measured using a platinum composite electrode (IWO61-BNC manufactured by Iwaki Glass).

Five test tubes containing 9 ml of sterilized water were prepared, and each of them was 20 ° C, 40 ° C, 60 ° C, 80 ° C, 10 ° C.
While maintaining each temperature of 0 ° C., 1 ml of the bacterial solution (subject to be sterilized) was added to each test tube. Immediately after the addition, 10 minutes, and 30 minutes later, 1 ml was sampled and the number of bacteria was examined by a general bacteria count test using a standard agar medium. For reference, water (distilled water) was maintained at a temperature of 80 ° C. and 100 ° C. and the same operation as described above was performed. The results are shown in Table 1.
Shown in

In the table, the unit of temperature is (° C.) and the unit of bacterial count is (cells / g). In addition, in order to know the number of bacteria in the bacterial solution added to each test tube, 1 ml of the bacterial solution was added to the test tube in which 9 ml of distilled water was kept at 20 ° C., and 1 ml was collected to examine the bacterial count. It was 960000 cells / g.

[0015]

[Table 1]

As is clear from Table 1, the sterilized water is kept at 20 ° C.
There is almost no bactericidal effect when used in, but when used in the state of 40 ℃, the bactericidal power is remarkably increased, and especially when the temperature is 80 ℃ or more, by contacting for about 30 minutes,
It turns out that it can be completely sterilized. Therefore, by applying the method of the present invention, it is possible to surely perform the sterilization treatment even when the same sterilizing water as the conventional one is used.

On the other hand, when simply using distilled water,
A decrease in the number of bacteria is observed at 100 ° C, but it is insufficient, and it can be said that at 80 ° C or lower, there is no bactericidal effect. Generally, 1% at 100 ° C is used to kill Bacillus subtilis spores.
The heat treatment for a long time of 7.5 to 18.5 hours is required, and the result supports this.

Example 2 To-be-sterilized objects (bacterial liquid) at various temperatures in sterilized water at room temperature
Was added to compare the sterilizing effect of sterilizing water. The same bacterial solution and sterilized water as in Example 1 were used.

9 ml of distilled water was added at 60 ° C. and 80 ° C., respectively.
Add the bacterial solution to the three test tubes held at 100 ℃ and 100 ℃,
After 10 minutes and 40 minutes, 1 ml was sampled to check the number of bacteria. Separately, 1 ml of the solution 10 minutes after the addition was added and added to 9 ml of sterilized water at room temperature, and the cells immediately after the addition and 30 minutes after the addition were added. I checked the number. However, this number of bacteria was diluted 10 times when added to sterilized water, so
Doubled The results are shown in Table 2. In addition, the temperature in the table,
The unit of the number of bacteria is the same as above. In addition, 60 ℃, 80 ℃,
The number of bacteria in the bacterial solution added to each test tube at 100 ° C. was 960000 cells / g as described above.

[0020]

[Table 2]

As is clear from Table 2, there is no significant change in the number of bacteria with distilled water at 60 ° C., and it can be seen that there is almost no bactericidal effect. However, when the bacterial solution was added to distilled water at 60 ° C. and 10 minutes after the bacterial solution was added to room temperature sterilized water, that is, when the bacterial solution heated to 60 ° C. was added to the sterilized water, immediately after addition Although the bactericidal effect is not clearly shown in 30%, the bactericidal number becomes 25000 cells / g after 30 minutes, indicating that sterilization has progressed compared to the case of holding in distilled water at 60 ° C for the same time, that is, 40 minutes. I understand.

Further, it can be seen that the higher the temperature of the distilled water, in other words, the higher the temperature of the object to be sterilized, the higher the sterilizing effect when brought into contact with the sterilizing water at room temperature. this is,
Even in bacteria in distilled water, the bacteria themselves are damaged as the temperature of the distilled water rises, and the damaged bacteria do not die much if they exist in the distilled water, It is thought that this is because when it comes into contact with sterilized water at room temperature, it will die. Furthermore, the sterilization effect can be further improved by raising the temperature of the sterilizing water at the same time as raising the temperature of the object to be sterilized.

Although the physical properties of the sterilized water were specifically specified and tested in both of the above-mentioned examples, generally, at room temperature, the pH was
Of 4.0 or less, redox potential of 820 mV or more, dissolved chlorine concentration of 1 to 200 ppm, dissolved oxygen concentration of 50 ppm
The following can be effectively used, and particularly, the pH is 3.0 or less, the redox potential is 1000 mV or more, the dissolved chlorine concentration is 5 to 200 ppm, and the dissolved oxygen concentration is 10 to 50.
When it is ppm, the bactericidal effect becomes higher.

[0024]

As described above, according to the sterilizing method of the present invention, the sterilizing water having a predetermined physical property value is brought into contact with the object to be sterilized at a predetermined temperature at room temperature, so that the sterilizing effect is significantly enhanced. It can be widely used for various purposes.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshifumi Ando 16-10 Takou, Yoshimi-cho, Hiki-gun, Saitama Japan Oxygen Co., Ltd.

Claims (3)

[Claims] 1. At room temperature, pH is 4.0 or less, redox potential is 820 mV or more, and dissolved chlorine concentration is 1 to 200 pp.
m, a sterilizing water having a dissolved oxygen concentration of 50 ppm or less and an object to be sterilized are brought into contact with each other at a temperature of 40 ° C. or more. 2. After raising the temperature of the object to be sterilized to 60 ° C. or higher, at room temperature, the pH is 4.0 or lower and the redox potential is 82.
A sterilizing method comprising contacting with sterilizing water having a dissolved chlorine concentration of 1 to 200 ppm and a dissolved oxygen concentration of 50 ppm or less at room temperature or higher, which is 0 mV or higher. 3. The sterilized water has a pH of 3.0 or less, an oxidation-reduction potential of 1000 mV or more, a dissolved chlorine concentration of 5 to 200 ppm, and a dissolved oxygen concentration of 10 to 50 ppm at room temperature. The sterilization method according to Item 1 or 2.