JPH10152116A - Sterilizing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the quantity of the deposit of phosphate in an evaporator while keeping the sterilizing effect and extend the maintenance period to remove the deposit, by using hydrogen peroxide water with a specified concentration range of phosphate added as a stabilizer. SOLUTION: Hydrogen peroxide water is evaporated by a heater and the evaporated hydrogen peroxide gas is used for sterilization. In this time, hydrogen peroxide water is used together with phosphate added as a stabilizer within 10-50ppm concentration. In this way, the phosphate deposit in the evaporator can be reduced while retaining the sterilizing effect and the period of maintenance to remove the deposit can be extended. And hence, the producing operation rate can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sterilization method applicable to an aseptic filling and packaging system for foods and medicines in which containers and devices are sterilized using vaporized hydrogen peroxide gas.

[0002]

2. Description of the Related Art Aqueous hydrogen peroxide is widely used as a tasteless and odorless disinfectant for disinfecting containers in aseptic filling and packaging systems and for disinfecting devices in aseptic chambers and pipes of aseptic filling and packaging systems themselves. As a usual usage method, in the case of sterilization of a container, a method of immersing the container in a hydrogen peroxide solution or spraying a hydrogen peroxide solution using a spray nozzle on a portion of the container requiring sterilization is used. On the other hand, in the case of sterilization of an apparatus, a method of spraying hydrogen peroxide water using a spray nozzle to a portion requiring sterilization is often used. Recently, in order to more efficiently sterilize the hydrogen peroxide solution, the hydrogen peroxide solution is once sprayed or dropped on a heater plate, and the hydrogen peroxide solution is vaporized on the heater. A so-called hydrogen peroxide gasification sterilization method has been used in which a sterilization effect is obtained by spraying a vaporized hydrogen peroxide gas onto a container or an apparatus.

[0003]

In the case of the sterilization method using hydrogen peroxide gas, a vaporizer for vaporizing the hydrogen peroxide solution is required. Further, in order to spray hydrogen peroxide gas to a container or the like to be sterilized, a hydrogen peroxide gas conduit attached to the vaporizer is required. This conduit is often of relatively small diameter.

[0004] On the other hand, a stabilizer such as a phosphate is added as an additive to the aqueous hydrogen peroxide for the purpose of improving storage stability. When gasifying hydrogen peroxide, the additive contained in the hydrogen peroxide solution adheres to the inside of the vaporizer or the conduit of the hydrogen peroxide gas as an evaporation residue and remains.

[0005] When such a sterilizing apparatus is used for a long period of time, the evaporation residue composed of the additive of hydrogen peroxide adheres to the surface of the vaporizing heater or the surface of the conduit. This continues to increase with each use, and the vaporization heater surface is completely covered with the evaporation residue, affecting the vaporization efficiency, and the inside of the conduit is clogged by the evaporation residue, and the hydrogen peroxide gas as a conduit Or lose their role. In order to remove the deposits due to the phosphate, maintenance by periodic decomposition is required.

[0006] Usually, this maintenance requires disassembly of the apparatus, so that the entire apparatus must be stopped for about one day, which has a large effect on a reduction in the production operation rate. The main component of this evaporation residue is phosphate. Since phosphate plays an important role as a stabilizer, it is a necessary component as an additive for hydrogen peroxide. In particular, when hydrogen peroxide water is vaporized, it is necessary to evaporate at a high temperature, which promotes decomposition of the hydrogen peroxide water during vaporization. Therefore, phosphate as a stabilizer is an essential additive.

Therefore, the present invention uses a hydrogen peroxide gas sterilization method in combination with a vaporizer using a hydrogen peroxide solution in which the amount of added phosphate is controlled, so that the phosphate sterilizing effect can be maintained while maintaining the sterilizing effect. An object of the present invention is to provide a sterilization method capable of reducing the amount of precipitation in a vaporizer and extending a maintenance period for removing precipitates.

[0008]

SUMMARY OF THE INVENTION The present invention has been conceived in order to solve the above-mentioned problems, and the invention of claim 1 is to provide a method for vaporizing hydrogen peroxide water on a heating heater to form a vaporized hydrogen peroxide gas. Is a sterilization method characterized by using a hydrogen peroxide solution in which the concentration of a phosphate added as a stabilizer is in the range of 10 ppm to 50 ppm. The invention according to claim 2 is the sterilization method according to claim 1, wherein the concentration of the phosphate added as the stabilizer is in the range of 10 to 30 ppm of hydrogen peroxide.

In order to solve the above-mentioned problems, the present invention provides practical stability of hydrogen peroxide and decomposition rate during gasification by controlling the amount of phosphate contained as an additive in hydrogen peroxide water. And minimize problems such as clogging of conduits composed of phosphate evaporation residues.

Further, by using the sterilization method using hydrogen peroxide gas according to the present invention, it is possible to reduce the amount of phosphate precipitates in the vaporizer caused by hydrogen peroxide additives while maintaining the sterilization effect. As a result, the maintenance period for removing the precipitate can be extended. Hereinafter, the present invention will be described in detail with reference to the drawings.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view showing an example of a sterilizer according to the present invention. The sterilization device is mainly configured by the vaporizer 1. The hydrogen peroxide solution 8 is supplied to the tank 7. The tank 7 is pressurized by compressed air to push out hydrogen peroxide. Spraying of the hydrogen peroxide into the vaporizer is performed by a two-fluid nozzle 4. A hydrogen peroxide line 9 and a compressed air line 14 are connected to the two-fluid nozzle, and have a structure in which hydrogen peroxide water or air flows by opening and closing the on-off valves 5 and 6, respectively. The valve is opened and closed by the control device 13. A preheater 12 is attached to the hydrogen peroxide line 9 and the compressed air line 14 to heat the hydrogen peroxide solution and air in advance. The compressed air line 14 is provided with a sterilization filter 10. The vaporizing device 1 has a vaporizing heater 2 for vaporizing the hydrogen peroxide solution. The vaporizer and the gas conduit 15 are provided with a dew condensation preventing heater 3 to suppress recondensation of the gas once vaporized. The container 17 has a sterilizing nozzle 16 via a gas conduit 15.
Is sprayed with hydrogen peroxide gas.

When the hydrogen peroxide gas is blown onto the container 17, a condensation film of hydrogen peroxide is formed on the surface of the container 17 due to the temperature difference between the hydrogen peroxide gas and the container 17.

In this test, a hydrogen peroxide gas is sprayed on the container 17 for about 1 second, and then at about 100 ° C. for the purpose of removing a condensed film of the hydrogen peroxide gas adhered to the container 17.
Of hot air was sprayed for about 10 seconds. Table 1 shows the results of a sterilization test and a test of the phosphate precipitation using this apparatus.

[0014]

[Table 1]

The hydrogen peroxide vaporization temperature was set at 150.degree. The two-fluid nozzle sprays about 1 ml of hydrogen peroxide solution per second, and sprays intermittently at one-second intervals. For the measurement of the precipitation state, the sterilizer was operated continuously for about 240 hours, and then the apparatus was disassembled and the state was observed.

For measurement of the bactericidal effect, B. su
Using btilis, about 10 ⁶ bacteria were uniformly applied to the inner surface of a 200-ml plastic cup, and the number of surviving bacteria after the sterilization treatment was measured.

Table 1 shows a list of the test results. Those containing no phosphates did not have any deposits on the vaporizer. However, as a result of the sterilization test,
Surviving bacteria were confirmed, and sufficient results were not obtained as a container sterilization method. This means that when the phosphate concentration is reduced to less than 10 ppm by removing the phosphate compounded as a stabilizer for the hydrogen peroxide solution, the decomposition of hydrogen peroxide by heat on the vaporizer rapidly proceeds, and This is presumed to be the result of the extremely reduced hydrogen peroxide concentration of the sprayed hydrogen peroxide gas. When hydrogen peroxide having a phosphate of 10 ppm or more was used, no surviving bacteria were observed in the sterilization test, and a good sterilizing effect was obtained.

On the other hand, it was confirmed that the amount of the precipitate on the vaporizer increased in proportion to the increase of the content of the phosphate. There is still no major problem at the concentration of about 30 ppm of phosphate, but when the addition amount exceeds 50 ppm, the amount of precipitation is very large, and a large amount of precipitated substances are found in the conduit for introducing hydrogen peroxide gas into the container. It was confirmed that there was a risk of blocking the conduit.

[0019]

According to the present invention, a hydrogen peroxide gas sterilization method is used in combination with a vaporizer using a hydrogen peroxide solution in which the amount of added phosphate is controlled. The amount of precipitation in the vaporizer can be reduced, the maintenance period for removing the precipitate can be extended, and the production operation rate can be improved.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing one example of a hydrogen peroxide vaporizer used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vaporizer 2 Vaporization heater 3 Dew condensation prevention heater 4 Two-fluid nozzle 5, 6 Opening / closing valve 7 Tank 8 Hydrogen peroxide water 9 Hydrogen peroxide line 10 Sterilization filter 11 Heater 12 Preheater 13 Control device 14 Compressed air line 15 Gas Conduit 16 Sterilization nozzle 17 Vessel

Claims (2)

[Claims] In a sterilization method in which hydrogen peroxide water is vaporized on a heater and the vaporized hydrogen peroxide gas is used, the concentration of a phosphate added as a stabilizer is 10%.
A sterilization method using a hydrogen peroxide solution in the range of ppm to 50 ppm. 2. The method according to claim 1, wherein the concentration of the phosphate added as a stabilizer is in the range of 10 ppm to 30 ppm.