JPH04174670A - Sterilizing method for food container - Google Patents

Abstract

PURPOSE:To provide a sterilizing method for a food container having no rest of chemicals by sterilizing the food container with ozonic water containing 5ppm or more of ozone concentration. CONSTITUTION:Gas liquid mixture prepared by a mixer 22 is supplied to an ozonic water supply pipe 20 after exhaust gas is separated through a separator 23. Thus, high concentration ozonic water is supplied as sterilizing and cleaning water to pouring and cleaning sections 9, 7 of a sterilizing apparatus 1. PET bottles 2 are sequentially sent from a sending section 3 of the sterilizing apparatus 1 into the apparatus. The PET bottle 2 has the outer and inner walls first cleaned with the ozonic water in the cleaning section 7. The bottle, after the cleaning, is mounted on a transfer section 13 through a reversing section 8 and the high concentration ozonic water is poured from a pouring nozzle 14 of the pouring section 9. Thus, since the high concentration ozonic water is poured into the PET bottle 2, bacterium deposited on the bottle 2 are sterilized by the ozonic water for sterizing the bottle 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for sterilizing food containers using ozone water.

[Prior Art] Generally, as methods for sterilizing food containers, heat sterilization, in which the food container is heated with steam or the like, and ultraviolet sterilization, in which an ultraviolet lamp is placed inside the food container and ultraviolet rays are directly emitted, are known.

The former type of heat sterilization can only be applied to heat-resistant materials such as glass bottles and cans, while the latter type of ultraviolet sterilization can only be applied to large items that can fit an ultraviolet lamp or items that can be expanded. However, the scope of use of both types of sterilization is limited. For example, food containers such as polyethylene terephthalate bottles (PET bottles) are sensitive to heat and do not transmit ultraviolet rays, so it is difficult to sterilize them by the above-mentioned heat sterilization or ultraviolet sterilization.

For this reason, currently, chemical sterilization is used to sterilize food containers such as PET bottles by bringing the food containers into contact with a chemical (mainly hydrogen peroxide).

[Problem to be solved by the invention] However, with chemical sterilization, there is a risk that residual substances may remain.
Due to the toxicity of the drug itself, it is harmful to the human body, impairs the flavor of food, and alters the quality of the food, so it is necessary to clean the product after sterilization. For this reason, in factories, etc.
We had to install a rinsing process to clean food containers after sterilization to deal with the residue.

Therefore, the present invention has been made in consideration of such circumstances, and its purpose is to provide a method for sterilizing food containers in which no chemical remains.

Means for Solving Two Problems] In order to achieve the above object, the present invention sterilizes food containers with ozonated water having an ozone concentration of 5 ppn or more.

[Function] Based on the knowledge regarding sterilization of food containers, the present inventors conducted various research and development on drug sterilization, and as a result, they investigated ozone sterilization and determined the ozone concentration in ozonated water based on this. It is.

That is, we focused on the fact that ozone sterilization, which is used to sterilize fresh foods such as foods, has a sterilizing effect and is also safe because it decomposes in a short time.

It is a well-established theory that ozone sterilization is not effective in sterilizing food containers.In other words, it was thought that no further improvement in sterilization ability (shortening of sterilization time) could be expected. Much stronger than Staphylococcus (highly resistant to heat, radiation, and chemicals) Several tens of minutes to kill approximately 105 bacterial spores of Bacillus subtilis (for example, commonly used Soak in ozonated water for about 30 minutes).

Therefore, as a result of conducting various studies on methods of contact between food containers and ozonated water, it was discovered that ozonated water with an ozone concentration of 5 ppn or more can be used as sterilizing water for food containers. If the ozone concentration is less than 5 ppm, it has a certain degree of sterilizing effect, but does not have sufficient sterilizing ability to carry out continuous sterilization.

Therefore, by filling a food container with ozonated water having an ozone concentration of 5 ppm or more or spraying it onto the inner or outer wall of the food container, bacteria attached to the food container can be sterilized by the ozonated water.

For example, if the ozonated water is used to sterilize the bacterial spores of Bacillus subtilis in the same manner as above, the bacterial spores can be sterilized within one minute, and the residual ozonated water decomposes into oxygen in several tens of minutes. It disappears naturally. In this way, food containers can be sterilized in a short time without any residual chemicals, and can be applied to devices that continuously sterilize food containers.

[Example 1] Hereinafter, an example of the present invention will be described based on the accompanying drawings.

In FIG. 1, reference numeral 1 indicates a sterilizing device for polyethylene terephthalate bottles (PET bottles) 2 used as food containers, and this sterilizing device 1 is installed in a line in a factory or the like.

The sterilizer 1 is provided with a carry-in part 3 for carrying the molded PET bottles 2 into the apparatus 1, and is also provided with a carry-out part 4 for carrying out the PET bottles 2 in the apparatus 1. The PET bottle 2 carried out is sent to the next step, for example, a filling step in which it is filled with drinking water such as juice. The sterilizer 1 is sealed with a cover 5, and the sterilizer 1 is sealed with a cover 5.
Gas (ozone gas) generated inside the tank is collected by an ozone killer 6 to prevent ozone gas from leaking into the atmosphere.

Inside the sterilizer l, the PET bottles 2 are transferred from the carry-in section 3 to the carry-out section 4, and the PET bottles 2 are sequentially transferred along the transfer route to a washing section 7, an inversion section 8, an injection section 9, and a drain section 10.
are arranged respectively.

The cleaning section 7 supports the PET bottle 2 from the loading section 3 with its mouth facing downward, and sprays cleaning water onto the outer wall of the bottle 2 or inserts a spray nozzle 11 into the bottle 2 to clean the inner wall of the bottle. It is configured to clean the bottle by spraying water on it. The washing section may be of any type as long as it washes the bottles, such as one that washes an appropriate number of bottles at the same time or one that washes the bottles while continuously moving them along the circumference. At the lower part of the washing section 7, a receiving section 12 is provided in which treated water after washing is collected.

The reversing unit 8 is disposed close to the cleaning unit 7 and
After washing, the bottle 2 is inverted and placed on a conveying section 13 such as a belt conveyor leading to a discharging section 4. An injection section 9 is disposed at the upper part of the transport section 13 on the upstream side in the transport direction, and the injection section 9 is configured to inject sterilized water through its injection nozzle 14 until it overflows into the bottle 2 on the transport section 13. has been done. The transport section 13 transports the bottle 2 filled with sterilized water, and the bottle 2 is sterilized with the sterilized water during this transport.

A drainage section 10 is disposed downstream of the transportation section 13 in the transportation direction, and this drainage section 10 discharges the ozonated water in the bottle 2 that has been transferred by the transportation section 13. The overflow water is collected in a storage part 15 provided at the lower part of the conveying part 13.

A conduit 18 having a cooler 16 and a pressure pump 17 is connected to the storage section 15 and the receiving section 12 .

This conduit 18 is connected to a high concentration ozone water production device 19, and the water accumulated in the storage section 15 and the receiver section 12 is cooled and pressurized before being supplied to the high concentration ozone water production device 19. It has become.

An ozonated water supply pipe 20 for supplying ozonated water as sterilizing water to the injection section and cleaning water to the cleaning section is connected to one high concentration ozonated water production device.

Further, an ultra-high concentration ozone generator 21 is connected to the high-concentration ozone water production apparatus 19, and the ultra-high concentration ozone generator 21 is configured to generate ozone gas having a gas phase ozone concentration of 6000 pp1 or more. Then, the high concentration ozone gas is pressurized and supplied to the high concentration ozone water production device 19.

The highly concentrated ozone water production device 19 is mainly composed of a mixer 22 that brings water and ozone scum into contact to mix gas and liquid, and a separator 23 that separates the exhaust gas component of the gas-liquid mixture from the mixer 22. has been done. The mixer 22 uses a static mixer, an ejector, etc., and is formed so that when the cooled and pressurized water comes into contact with the high concentration ozone gas, the contact area of the water is wider than before. It is configured to produce ozonated water having a liquid phase ozone concentration of 5 ppi or more. Note that water to the highly concentrated ozonated water production apparatus is supplied from a storage section or the like, but if the storage section or the like lacks water, makeup water is supplied as appropriate.

Now, high-concentration ozone gas (scum with a gas phase ozone concentration of 6000 ppm or more) is supplied from the ultra-high concentration ozone generator W21 to the mixer 22 of the high-concentration ozone water production device 19, and cooled and pressurized water is It is supplied via conduit 18. Then, the water and the highly concentrated ozone gas come into gas-liquid contact under high pressure in the mixer 22, and a gas-liquid mixture (ozone water) having a liquid phase ozone concentration of 5 ppn or more is produced. Simply blowing ozone gas into water and bringing it into gas-liquid contact can only produce ozonated water with an ozone concentration of about 1 ppn at most, but by lowering the temperature of the water and increasing the pressure, Henry's law allows the ozone gas to reach near saturation. Moreover, since the mixer 22 is formed so that the contact area between gas and water is large, it is possible to reliably dissolve ozone gas in water. This makes it possible to produce highly concentrated ozonated water with an ozone concentration of 5 pp11 or more.

The gas-liquid mixture produced in the mixer 22 is supplied to the ozone water supply pipe 20 after the exhaust gas component is separated through the separator 23 . Thereby, highly concentrated ozonated water is supplied to the injection section 9 and the cleaning section 7 of the sterilizer 1 as sterilizing water and cleaning water.

The PET bottles 2 are sequentially carried into the apparatus from the carry-in section 3 of the sterilizer 1.
Then, the outer and inner walls are cleaned with ozonated water. After cleaning, it is mounted on the transport section 13 via the reversing section 8, and highly concentrated ozone water is injected from the injection nozzle 14 of the injection section 9.

In this way, by injecting highly concentrated ozonated water into the PET bottle 2, bacteria adhering to the bottle 2 are sterilized by the ozonated water, and the bottle 2 is sterilized.

As a result, the bottles 2 are sterilized while moving on the transport section 13, and after sterilization, the sterilized water is drained in the drainage section 10, and then transported out of the sterilizer 1 from the discharging section 4. It is sent to a filling process where it is filled with drinking water such as juice.

The water drained from the bottle 2 in the drainage section 10 is transferred to the conveyance section 13
After that, the water in the cleaning part 7 is supplied to the highly concentrated ozonated water production device 19 together with the water stored in the part 12 via the conduit 18 to be reused.

Here, bacterial spores of Bacillus subtilis (initial number of bacteria: average i, ex 10' (cell
1/1)) was sterilized. The number of remaining bacteria at these sterilization times was investigated, and the results are shown in Table 1.

However, the cell to which the bacterial spores were attached was immersed in ozonated water at about 20° C. to check the sterilization state, and this was repeated three times a, b, and c for each concentration.

From the results shown in Table 1, in the case of 10 ppm concentration, a
For both , b, and c, several dozen bacteria remained when the sterilization time was 20 seconds, and several bacteria remained when the sterilization time was 40 seconds, but the number of remaining bacteria decreased to zero when the sterilization time reached 60 seconds. In case of 25 ppn concentration, sterilization time is 20
After 40 seconds, bacteria a, b, and c remained, but after 40 seconds, the number of remaining bacteria decreased to zero. Therefore, when bacterial spores of Bacillus subtilis are sterilized using highly concentrated ozonated water, the bacterial spores can be sterilized within one minute.

Therefore, bacteria adhering to the food container (PET bottle) 2 can be sterilized within one minute using the highly concentrated ozone water. Thereby, even if highly concentrated ozone water is used as a sterilizer in the sterilizer 1, the PET bottles 2 can be continuously sterilized. Further, even if ozonated water remains in the PET bottle 2, it will decompose into oxygen and disappear naturally in several tens of minutes, so there is no need to clean the PET bottle 2 after sterilizing it. Therefore, there is no need to install a rinsing process for washing the PET bottles 2 inside the sterilizer 1 or after the sterilizer 1, which is conventionally necessary.

In this embodiment, the food container is a PET bottle, but the food container is not limited to this, and it goes without saying that other food containers can also be sterilized with highly concentrated ozonated water.

[Effects of the Invention] In summary, the present invention exhibits an excellent effect in that there is no residual drug and food containers can be sterilized in a short time.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of a food container sterilization apparatus to which the food container sterilization method according to the present invention is applied. In the figure, 2 indicates a food container, and 19 indicates a high concentration ozone generator.

Claims (1)

[Claims] 1. A method for sterilizing food containers, characterized in that the food containers are sterilized with ozonated water having an ozone concentration of 5 ppm or more.