JP7709263B2 - Liquid paper container for sterility confirmation testing of aseptic filling machine for liquid paper containers and sterility confirmation test method - Google Patents

Description

The present invention relates to a liquid paper container for sterility confirmation testing of a liquid paper container aseptic filling machine that fills a liquid medium when checking the sterility of a liquid paper container aseptic filling machine, and a sterility confirmation test method.

Conventionally, liquid paper containers are filled with a variety of liquid contents, such as milk, dairy drinks, soy milk, green tea, black tea, coffee, juice, sake, shochu, wine, and seasonings. Of these liquid contents, milk, dairy drinks, green tea, black tea, coffee, juice, etc., which are not suitable for hot filling or whose taste deteriorates when hot filled, are filled into liquid paper containers using an aseptic filling and packaging machine for liquid paper containers.

There are two types of aseptic filling machines for liquid paper containers: one is to sterilize the liquid paper container sheet, which is supplied in a rolled form, by immersing it in a disinfectant and drying it, and then filling the sterilized liquid contents while forming the container in a sterile atmosphere, and the other is to supply a blank that will become a liquid paper container to the aseptic filling machine for liquid paper containers, and fill the sterilized liquid contents while forming the blank into a container in a sterile atmosphere.

As an example of the latter aseptic filling machine for liquid paper containers, a sterilization method for liquid paper containers has been proposed in which a mist of hydrogen peroxide solution is sprayed onto the inside and outside surfaces of the liquid paper container and the mist adhering to the surface of the liquid paper container is dried (Patent Document 1). Also proposed is a sterilization method for liquid paper containers in which hydrogen peroxide gas is sprayed onto the liquid paper container and the hydrogen peroxide condensed on the surface of the liquid paper container is dried by hot air (Patent Document 2).

On the other hand, because liquid paper containers are made of paper, they have the disadvantage that the contents cannot be seen, unlike containers made of film or PET bottles. Therefore, it has been proposed to create a liquid paper container that allows the contents to be seen by forming a cutout in part of the liquid paper container and attaching a transparent film to this part (Patent Documents 3, 4, 5, 6).

Japanese Patent Application Publication No. 9-240629 Japanese Patent Application Publication No. 10-119934 Japanese Utility Model Application Publication No. 56-138025 Japanese Utility Model Application Publication No. 03-003532 Japanese Patent Application Publication No. 11-227752 JP 2016-8060 A

Aseptic filling machines are widely used to fill sterilized containers with sterilized contents in a sterile atmosphere and then seal the filled containers with sterilized lids. Aseptic filling machines fill containers with contents at room temperature, they can minimize deterioration of the contents due to heat. As a result, the contents have an excellent taste. Another advantage is that the contents can be stored at room temperature because the sterility of the product is maintained due to aseptic filling, and so they are being used for a wide variety of contents.

It must be demonstrated that the products produced by aseptic filling machines maintain the sterility of the product. To demonstrate the sterility of aseptic filling machines, containers are fed into the aseptic filling machine before sterilization, with or without bacteria attached to them, the sterilized containers are filled with liquid medium, the containers filled with liquid medium are sealed, the sealed containers are stored at an appropriate temperature for an appropriate period of time, and it is visually confirmed whether bacteria are growing in the liquid medium.

When bacteria are attached to containers, several hundred containers are used. This test is conducted to measure the sterilization capacity of an aseptic filling machine. However, to demonstrate the sterility of an aseptic filling machine, tens of thousands of containers that are actually used are fed into the machine and filled with sterilized liquid medium instead of the actual contents. The liquid medium filled in such a large number of containers must be visually inspected for the presence or absence of bacterial growth.

When a liquid medium is filled into a sterilized container and stored at an appropriate temperature for an appropriate period of time, if bacteria are growing in the container, the liquid medium will become cloudy. If bacteria are not growing, the liquid medium will be clear and not cloudy, just like before filling. Normally, the sterilization capacity of an aseptic filling machine is required to be 6 log reduction (6 LRV). Therefore, in a sterility confirmation test involving tens of thousands of bottles, if even one bottle of liquid medium becomes cloudy, the aseptic filling machine is deemed not to be sterile.

If the container is transparent, such as a PET bottle, the turbidity of the liquid medium can be instantly judged by visually inspecting its appearance, even when the container is filled with tens of thousands of bottles of liquid medium. However, if the container is a paper container, the liquid medium filled in the container cannot be visually inspected from the outside of the container, so an instantaneous judgment cannot be made. In order to visually inspect the liquid medium, the paper container must be destroyed to make it possible to visually inspect the liquid medium. For example, it would be extremely laborious to determine the turbidity of liquid medium filled in tens of thousands of paper containers while cutting out the headspace portion at the top of the paper container.

Therefore, when checking the sterility of an aseptic filling machine for liquid paper containers, a method is required that allows for visual inspection of the appearance of the liquid medium, as with PET bottles, without destroying the liquid paper container, to be confirmed for cloudiness.

The present invention has been made to solve the above problems, and relates to a liquid paper container for sterility confirmation testing of a liquid paper container aseptically filling a liquid paper container, and a sterility confirmation test method that can easily check for turbidity of the liquid medium filled in the liquid paper container without destroying the liquid paper container when checking the sterility of the liquid paper container aseptically filling a liquid paper container.

The liquid paper container for sterility confirmation testing is supplied to a liquid paper container aseptic filling machine which sprays a disinfectant gas onto the inner surface of the liquid paper container, and the liquid paper container is made of at least laminated paper, and has a notch in a wall surface having an opaque layer, the notch is sealed with a transparent member, and an end of the transparent member is completely heat-sealed to the inner surface of the liquid paper container . The liquid paper container is filled with liquid medium at 1/5 to 4/5 of the volume of the liquid paper container, and after sealing the liquid paper container, the liquid paper container is vibrated so that the liquid medium comes into contact with the entire inner surface of the liquid paper container, and after culturing the liquid medium, the liquid medium is visually observed through the transparent member.

Furthermore, in the sterility confirmation test method for a liquid paper container aseptic filling machine of the present invention, it is preferable to irradiate light onto one of the transparent members of a liquid paper container for sterility confirmation test, in which the cutout portions are provided at two or more opposing locations on the wall of the liquid paper container, and to visually observe the liquid culture medium through the other transparent member. The liquid paper container for sterility confirmation testing is supplied to a liquid paper container aseptic filling machine that sprays a disinfectant gas onto the inner surface of the liquid paper container, and the liquid paper container is made of at least laminated paper, and a notch is provided in a wall surface having an opaque layer, the notch is sealed with a transparent member, and an end of the transparent member is completely heat-sealed to the inner surface of the liquid paper container.The liquid paper container is filled with liquid medium at 1/5 to 4/5 of the volume of the liquid paper container, and after sealing the liquid paper container, the liquid paper container is vibrated so that the liquid medium comes into contact with the entire inner surface of the liquid paper container.After culturing the liquid medium, light is irradiated from the transparent member and received by the other transparent member, thereby measuring the transmittance or absorbance.

According to the present invention, by using a liquid paper container for sterility confirmation testing in which a cutout is provided in the wall surface having an opaque layer of the liquid paper container and the cutout is sealed with a transparent member, it is possible to visually check the presence or absence of turbidity in the liquid medium when checking the sterility of an aseptic filling machine for liquid paper containers without destroying the liquid paper container filled with the liquid medium, and compared to the conventional method in which a part of the liquid paper container was cut out to check the presence or absence of turbidity in the liquid medium, the sterility confirmation test for the aseptic filling machine for liquid paper containers can be performed in a short time.

In addition, by providing cutouts in at least two opposing locations on the wall of the liquid paper container, light can be irradiated onto one of the transparent members and the liquid medium can be visually observed through the other transparent member, making it possible to perform a sterility confirmation test of the aseptic filling machine for liquid paper containers more quickly and reliably.

1 is a schematic side view showing an example of an aseptic filling machine for liquid paper containers according to an embodiment of the present invention. FIG. 1 shows a blank for a liquid paper container for a sterility confirmation test according to an embodiment of the present invention. 1 shows a sleeve of a liquid paper container for sterility confirmation testing according to an embodiment of the present invention. 1 shows the state of a liquid-containing paper container for a sterility confirmation test after molding according to an embodiment of the present invention. 1 is a cross-sectional view showing a portion of a liquid-containing paper container for a sterility confirmation test, illustrating a state in which a notch in the liquid-containing paper container for a sterility confirmation test is sealed, in accordance with an embodiment of the present invention. 1 shows a blank for a liquid-containing paper container for a sterility confirmation test, in which cutouts are provided at two opposing locations on the wall of the liquid-containing paper container, according to an embodiment of the present invention. 1 shows a state after molding of a liquid-filled paper container for a sterility confirmation test, in which notches are provided at two opposing locations on the wall surface of the liquid-filled paper container, according to an embodiment of the present invention.

The following describes the embodiment of the present invention with reference to the drawings.

(Overview of aseptic filling machine and process for liquid cartons)
1, an aseptic filling machine 1 for liquid paper containers according to this embodiment includes a sleeve supplying device 2, a bottom assembling device 5 that receives sleeves 3 supplied from the sleeve supplying device 2 and sterilizes the outer surface of the sleeve 3 to be formed into a liquid paper container 4 and forms the bottom of the liquid paper container 4, a conveyor 6 that transports the liquid paper container 4 with the formed bottom, an inner surface sterilizing device 7 that sterilizes the inner surface of the liquid paper container 4, a filling device 8 that fills the liquid paper container 4 with the contents, and a head sealing device 9 that seals the liquid paper container 4 after filling. These devices are located inside an aseptic chamber 10.

The sleeve 3 shown in FIG. 3 is introduced into the sterile chamber 10 by the sleeve supply device 2. The sleeve 3 is inserted into the mandrel 12 provided on the turret 11, leaving only the portion necessary for blocking. Furthermore, the inner surface of the sleeve 3 on the blocked side where the mandrel 12 is not inserted, and the outer surface of the sleeve 3 are sterilized by the bottom sterilization device 13. After sterilization, the remaining sterilizing agent is removed by hot air blown by the drying device 14.

The sleeve 3 is then folded along the crease that forms the bottom of the liquid-carton container 4 by the bottom crease folding device 15, and the part that was heated by the drying device 14 is crimped by the bottom sealing device 16. In this way, one side of the open end of the sleeve 3 is closed, and the sleeve 3 is formed into a bottomed, cylindrical liquid-carton container 4.

The liquid paper container 4 with its bottom formed is intermittently transported by the conveyor 6, while sterilant gas is sprayed onto the inner surface of the liquid paper container 4 from a nozzle 17 provided on the inner surface sterilization device 7. The sterilant sprayed onto the liquid paper container 4 is removed by hot air sprayed onto the inner surface of the liquid paper container 4 from a hot air nozzle 18. The liquid paper container 4 with its inner surface sterilized is filled by the filling device 8 with contents sterilized by a separately provided device. Furthermore, the head crimping device 19 folds the crease at the head of the liquid paper container 4, the inner surface is heated by the head heating device 20, and the head is crimped by the head sealing device 9 to seal the liquid paper container 4. The sealed liquid paper container 4 is discharged from the aseptic chamber 10.

(Sterility confirmation test)
Before operating the aseptic filling machine for liquid paper containers 1, a COP (Cleaning Out of Place) process is performed inside the aseptic chamber 10 to clean the inside of the aseptic chamber 10, and a SOP (Sterilizing Out of Place) process is performed inside the aseptic chamber 10. Also, a CIP (Cleaning In Place) process is performed to clean the inside of the content supply system piping, and a SOP (Sterilizing In Place) process is performed to sterilize the inside of the content supply system piping. After the aseptic filling machine for liquid paper containers 1 is installed and before it is operated for the first time, and after regular repairs are performed and before it is operated for the first time, COP, SOP, CIP, and SIP processes are performed, and then a sterility confirmation test of the aseptic filling machine for liquid paper containers 1 is performed.

The sterility confirmation test is performed by supplying the sleeve 3 to the sleeve supply device 2 and operating the aseptic filling machine 1 for liquid paper containers under normal operating conditions. The sleeve 3 in this embodiment is shown in Figure 3. The sleeve 3 is made of at least laminated paper, has a body lining 21 to form a cylindrical shape, and has body forming lines 22a, bottom forming lines 22b, and head forming lines 22c for folding when forming the liquid paper container 4. The sleeve 3 is obtained by joining the body lining 21 of the blank 23 shown in Figure 2 to the inside of the end of the blank 23. The blank 23 has a cutout 24 in the wall surface having the opaque layer of the liquid paper container 4, and the cutout 24 is sealed with a transparent member 25.

The body attachment section 21 of the sleeve 3 is formed by heat sealing the inner and outer surfaces of the sleeve 3. Here, the end face of the inner laminate of the body attachment section 21 is formed so that it is not exposed. This is done by hemming the tip of the inner end outward, by skive hemming the inside of the tip and then cutting and folding it outward, or by attaching a tape with heat sealability on both sides to the end. This prevents bacteria from migrating to the contents from the end face of the paper of the laminate on the inside of the body attachment section 21, and prevents the contents from penetrating the paper.

The sleeve 3 is folded along the body forming lines 22a to form a roughly rectangular tube, but if the lines are shallow or the paper is thin, the sides of the cross-sectional shape of the tube may be arc-shaped. Also, if some parts are not lined, the cross section of those parts of the sleeve 3 may be roughly circular. Furthermore, some parts may be polygonal, such as hexagonal, rather than rectangular.

The blank 23 has a layer of a thermoplastic resin such as polyethylene or polypropylene that can be heat-sealed on both sides of the paper. If necessary, a film on which a metal or metal oxide such as aluminum foil, aluminum, silicon oxide, or aluminum oxide is vapor-deposited, a thermoplastic resin having a barrier property such as an ethylene-vinyl alcohol copolymer or a copolymer of an aromatic diamine and a dibasic acid, or the like may be provided as a layer on the inside of the paper. Printing may be provided on the outside or outermost surface of the paper. One or more layers of adhesive or thermoplastic resin having adhesive properties may be provided as an intermediate layer. For example, the blank 23 may be configured as polyethylene/printing/paper/polyethylene, polyethylene/printing/paper/polyethylene or ethylene-methacrylic acid copolymer/aluminum foil/polyethylene, printing/polyethylene/paper/polyethylene/ethylene-vinyl alcohol copolymer/polyethylene, printing/polyethylene/paper/ethylene-methacrylic acid copolymer/polyester film with vapor deposition of silica/adhesive/polyethylene, etc. The basis weight of the paper to be laminated is preferably 80 g/m ² to 500 g/m ² . If the thickness is less than 80 g/ ^m2 , the paper container will not have the shape retention, and if the thickness exceeds 500 g/ ^m2 , processing will be difficult. The heat-sealable layer is preferably 15 μm to 150 μm. If the thickness is less than 15 μm, sufficient heat seal strength cannot be obtained, and if the thickness exceeds 150 μm, the heat seal strength is sufficient, so it is excessive. Such a laminate is punched and a score line is provided at the same time to obtain the blank 23.

The notch 24 is provided at the same time as punching, and then, as shown in FIG. 5, a transparent member 25 is attached to the blank 23 so as to cover the notch 24, thereby sealing the liquid paper container 4. The notch 24 is provided on the wall surface of the liquid paper container 4, and the size, shape, and position are arbitrary. The size of the notch 24 does not matter as long as the liquid medium filled in the liquid paper container 4 can be visually recognized, but 1 cm ² to 200 cm ² is appropriate. The shape of the notch 24 is a simple shape, and for example, a circle, a square, an ellipse, or a shape combining these is preferable. In the sterility confirmation test of the liquid paper container aseptic filling machine 1, the liquid paper container 4 is filled with the liquid medium in an amount approximately equal to the volume of the liquid paper container 4, or in other cases, but generally, about 1/5 to 4/5 of the volume is filled to reduce costs. Therefore, in order to visually recognize the liquid medium, it is preferable to position the notch 24 toward the lower part of the liquid paper container 4.

As shown in FIG. 5, the cutout 24 provided in the opaque laminate 26 having at least a paper layer of the blank 23 is sealed by attaching the transparent member 25 by heat sealing. The transparent member 25 is made of a transparent plastic film, and must have a layer on one side that can be heat sealed to the surface of the laminate 26 that will become the inner surface of the liquid paper container 4.

If the inner surface of the liquid paper container 4 of the laminate 26 is polyethylene, the transparent member 25 has a polyethylene layer on one side. The polyethylene layer is laminated with a biaxially oriented film such as polyethylene terephthalate, polypropylene, polyamide, or ethylene-vinyl alcohol copolymer, or a film in which a vapor-deposited layer of a transparent metal oxide such as silicon oxide or aluminum oxide is provided on the biaxially oriented film. There may be one or more films laminated, and multiple films may be combined and laminated. Also, a single layer of polyethylene may be used without laminating a film on the polyethylene. The polyethylene layer is preferably 15 μm to 150 μm. If it is less than 15 μm, sufficient heat seal strength cannot be obtained, and if it exceeds 150 μm, the heat seal strength is sufficient and therefore excessive. Also, the film laminated on the polyethylene is preferably 6 μm to 50 μm.

The transparent member 25 is attached to the laminate 26 by heat sealing. At least the end of the transparent member 25, which has an area larger than the cutout 24, is heat sealed to the laminate 26. It is preferable that the end of the transparent member 25 is completely heat sealed. This is because if there is a gap between the transparent member 25 and the laminate 26, bacteria in the gap may not be sterilized in the inner surface sterilization process of the liquid paper container 4 of the liquid paper container aseptic filling machine 1.

The transparent member 25 is punched out in advance to a predetermined shape, and the punched out transparent member 25 is placed over the cutout portion 24 of the blank 23 and heat sealed. Alternatively, the transparent member 25 may be supplied in a roll form, punched out to a predetermined shape leaving a portion, and heat sealed continuously while breaking the remaining punched portion at the same time as heat sealing.

When sealing the cutout 24 with the transparent member 25, the working environment must be kept clean to prevent new bacteria from adhering to the blank 23. For example, the room in which the work is carried out must be a clean room, with clean air that has passed through a sterilizing filter supplied from above. The heat sealing work is also carried out on a clean bench to which clean air is supplied. Furthermore, the blank 23 and transparent member 25 to be heat sealed must be mechanized so that they are not touched by human hands. Alternatively, after the transparent member 25 is attached to the cutout 24, the blank 23 can be sterilized with a disinfectant such as ethylene oxide gas or hydrogen peroxide.

Although the case where the notch 24 is punched out at the same time as punching out the blank 23 has been described, the notch 24 may be provided in the roll-shaped laminate up to the layer having the opaque layer of the laminate that will become the blank 23, for example at the stage where paper and aluminum foil are laminated, and a transparent member 25 may be laminated on the entire surface of the layer that will become the inner surface side of the liquid paper container 4, and then the blank 23 may be punched out. For example, polyethylene may be laminated on the surface of the aluminum foil, or a biaxially oriented polyethylene terephthalate film may be laminated, and then polyethylene may be laminated on the surface of the biaxially oriented polyethylene terephthalate film.

In addition, when aluminum foil is not laminated, polyethylene is laminated on the outer surface of the paper, and then a notch 24 is provided in the roll-shaped laminate, and a film in which a biaxially oriented film is provided with a vapor-deposited layer of a transparent metal oxide such as silicon oxide or aluminum oxide is laminated on the entire surface of the layer that will become the inner surface of the liquid paper container 4, and then polyethylene is laminated. Alternatively, a transparent member 25 in which a polyethylene layer is laminated on a film in which a biaxially oriented film is provided with a vapor-deposited layer of a transparent metal oxide such as silicon oxide or aluminum oxide is laminated may be laminated on the layer that will become the inner surface of the liquid paper container 4. Then, the blank 23 is punched out.

The sleeve 3, in which the notch 24 is sealed with the transparent member 25, is supplied to the aseptic filling machine 1 for liquid paper containers that has completed COP, SOP, CIP, and SIP, and a sterility confirmation test for the aseptic filling machine 1 for liquid paper containers is performed. The number of liquid paper containers 4 to be supplied is appropriately 1,000 to 100,000. Sterility cannot be guaranteed if there are fewer than 1,000 containers. If there are more than 100,000 containers, the test cost becomes high, the number of blanks 23 to be subjected to the sterility confirmation test increases, and it takes a long time to visually check the filled liquid medium after cultivation, making the work complicated. Normally, the sterility of the aseptic filling machine 1 for liquid paper containers is required to be 10 ^-6 (CFU/unit), so even if 100,000 containers are subjected to the sterility confirmation test, not even one sterilization failure is permitted.

Bacteria may be attached to the inner surface of the sleeve 3, and a sterility confirmation test of the aseptic filling machine for liquid paper containers 1 may be performed based on the sterilizing effect of the number of attached bacteria. For example, 1 g of indicator bacteria of 10 ⁴ [cfu/g], 10 ⁵ [cfu/g], or 10 ⁶ [cfu/g] is attached to the inner surface of the sleeve 3, and the indicator bacteria is supplied to the aseptic filling machine for liquid paper containers 1, a liquid medium is filled, and after cultivation, the liquid medium is visually observed through the transparent member 25 to confirm whether the liquid medium is turbid or not. If the liquid medium filled in the sleeve 3 to which ^{10 6} [cfu/g] of indicator bacteria is attached is not turbid, the sterility of the aseptic filling machine for liquid paper containers 1 is 6LRV. The sterility confirmation test performed by attaching bacteria to the inner surface of the sleeve 3 is performed with 3 to 1000 indicator bacteria for each order.

The sterility confirmation test for the aseptic filling machine 1 for liquid paper containers is preferably performed by combining a test in which a large number of blanks are supplied and a test in which bacteria are attached to the inner surface of the blank 23. In either case, the liquid medium is filled and the turbidity of the liquid medium is visually confirmed after cultivation, but the sterility confirmation test can be easily performed by visually confirming the turbidity of the liquid medium after cultivation through the transparent member 25 that seals the cutout portion 24 of the liquid paper container 4.

After the sleeve 3 is transported to the sterile chamber 10, the inner surface is heat-sealed to form the bottom. The heat seal can be performed by heating the inner surface with hot air, folding the triangular portion of the bottom forming line 22b inward and pressing the apexes of the triangle together, or by turning the triangular portion outward and folding the triangular portion toward the side of the liquid paper container 4 after pressing and attaching it to the outer surface of the liquid paper container 4, or by folding it toward the heat-sealed portion to form the bottom. The heat seal can also be performed by turning the triangular portion outward and using heat sealing by external heating, ultrasonic heat sealing, or high-frequency heat sealing if the sleeve 3 contains aluminum foil as a layer.

The liquid paper container 4 with the molded bottom is intermittently transported by the conveyor 6, while the sterilant gas generated by the sterilant gas generator is sprayed onto the inner surface of the liquid paper container 4 from the nozzle 17 provided on the inner surface sterilization device 7. The sterilant in this embodiment preferably contains at least hydrogen peroxide. The appropriate content is in the range of 0.5% to 65% by mass. If it is less than 0.5% by mass, the sterilizing power may be insufficient, and if it exceeds 65% by mass, it becomes difficult to handle for safety reasons. Furthermore, 0.5% to 40% by mass is more preferable, and if it is 40% by mass or less, it is easier to handle and the low concentration reduces the amount of sterilant remaining after sterilization.

The disinfectant contains water, but may also contain one or more of alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, normal propyl alcohol, and butyl alcohol, ketones such as acetone, methyl ethyl ketone, and acetylacetone, and glycol ethers.

Furthermore, the disinfectant may contain additives such as peracetic acid, acetic acid, chlorine compounds, ozone, and other compounds with disinfecting effects, cationic surfactants, nonionic surfactants, and phosphate compounds.

Hot air is sprayed from the hot air nozzle 18 onto the inner surface of the liquid paper container 4, the inner surface of which has been sprayed with disinfectant, and the sprayed disinfectant is removed. In addition, sterile air may be sprayed onto the inner surface of the liquid paper container 4.

The liquid paper container 4, the inner surface of which has been sterilized, is filled with sterilized liquid culture medium by the filling device 8. Because the liquid culture medium is relatively expensive, an amount less than the capacity of the liquid paper container 4 is filled. Approximately 1/5 to 4/5 of the capacity of the liquid paper container 4 is appropriate. Because the amount of liquid culture medium filled is less than the capacity of the liquid paper container 4, after sealing the top of the liquid paper container 4, the liquid paper container 4 is vibrated so that the liquid culture medium comes into contact with the entire inner surface of the liquid paper container 4.

A liquid medium is generally made by dissolving in water the following carbon sources: organic carbon sources such as glucose, dextrose, and other monosaccharides, disaccharides, and polysaccharides; inorganic carbon sources such as sodium carbonate and sodium bicarbonate at 0.2-3% by weight; nitrogen sources (including coenzymes) such as casein peptone, chicken peptone, myocardial peptone, gelatin peptone, soybean peptone, polypeptone, yeast extract, meat extract, ammonium sulfate, magnesium sulfate, and nitrates at 0.5-3% by weight; and trace minerals or buffers such as sodium chloride, potassium monophosphate, potassium monohydrogen phosphate, and potassium dihydrogen phosphate at 0.05-1% by weight.

The pH of the liquid medium is adjusted by dissolving hydrochloric acid, tartaric acid, citric acid, sodium hydroxide, potassium hydroxide, etc. in the liquid medium. The pH of the liquid medium is adjusted to be acidic in accordance with the pH of the contents. For example, in the case of a low-acid beverage with a pH of 4.5 or higher, the pH of the liquid medium is preferably adjusted to 7.0±0.2. In the case of a high-acid beverage with a pH of less than 4.5, the pH of the liquid medium is preferably adjusted to 4.0±0.2. The liquid medium is prepared in advance and heat sterilized before being filled in the filling machine.

The liquid paper container 4 filled with the liquid medium is then folded along the head forming line 22c by the head folding device 19, the inner surface is heated by the head heating device 20, and the head is crimped and sealed by the head sealing device 9. The sealed liquid paper container 4 is stored at an appropriate temperature.

The liquid paper container 4 filled with the liquid culture medium is stored at a temperature of 25°C to 35°C for 3 to 21 days, preferably 7 days or more. During storage, it is vibrated as described above so that the liquid culture medium comes into contact with the entire inner surface of the liquid paper container 4.

After the liquid medium filled in the liquid paper container 4 is cultivated at an appropriate temperature for an appropriate period of time, the liquid medium is visually observed through the transparent member 25 that seals the notch 24 of the liquid paper container 4, and the sterility of the liquid paper container aseptic filling machine 1 is confirmed by determining whether the liquid medium is cloudy or not. If the liquid medium is cloudy, the sterility of the liquid paper container aseptic filling machine 1 is not guaranteed. If the liquid medium of all liquid paper containers 4 that have undergone a sterility confirmation test is transparent, the sterility of the liquid paper container aseptic filling machine 1 is guaranteed according to the number of liquid paper containers subjected to the sterility confirmation test. In addition, in a sterility confirmation test in which bacteria or the like is attached to the inner surface of the sleeve 3, the sterility performance of the liquid paper container aseptic filling machine 1 is judged according to the order of the attached bacteria or the like.

The liquid paper container 4 for sterility confirmation testing is supplied to the aseptic filling machine for liquid paper containers 1, and a notch 24 is provided in the wall surface having an opaque layer, and the notch 24 is sealed with a transparent member 25. The liquid medium is filled into the liquid paper container 4 for sterility confirmation testing, and the liquid medium is visually observed through the transparent member 25 after culturing the liquid medium, thereby confirming the sterility of the aseptic filling machine for liquid paper containers 1. However, if there is only one notch 24, it may be difficult to determine whether the liquid medium is cloudy or not. Therefore, it is preferable to provide the notch 24 in two or more opposing places on the wall surface of the liquid paper container 4, irradiate light onto one of the transparent members 25 of the liquid paper container 4 of the aseptic filling machine for liquid paper containers 1, and visually observe the liquid medium through the other transparent member 25.

The blank 23 shown in FIG. 6 has two notches 24 at approximately the same positions on opposing sides of the wall of the liquid paper container 4. The two notches 24 are sealed with transparent members 25. By shining light onto one transparent member 25 of the liquid paper container 4 filled with and cultured with liquid culture medium and visually checking through the other transparent member 25, it is easier to determine whether the liquid culture medium is cloudy or not compared to when only one notch 24 is provided.

A blank 23 with two notches 24 as shown in Figure 6 is formed into a liquid paper container 4, and the liquid medium is filled in such a way that when the liquid paper container 4 is left to stand as shown in Figure 7, the liquid level of the liquid medium is above the transparent member 25. Light is irradiated from one of the transparent members 25 and viewed through the other transparent member 25. The presence or absence of turbidity in the liquid medium can be instantly determined by the transmitted light. Even without irradiating light from one of the notches 24, the presence or absence of turbidity in the liquid medium can be sufficiently determined by the amount of normal outside light that passes through the liquid medium from the transparent member 25 that seals one of the notches 24.

The blank 23 shown in FIG. 6 has two notches 24, but it is acceptable for there to be three or more notches 24. For example, it is acceptable for notches 24 to be provided on each of the opposing surfaces, or for notches 24 to be provided on another wall surface.

In addition to visually checking the turbidity of the liquid culture medium, an inspection machine may be installed and an inspection device (turbidity meter) that utilizes the principles of a spectrophotometer may be used to determine whether the liquid culture medium is turbid or not. Light is irradiated from one transparent member 25 and received by the other transparent member 25 to measure the transmittance or absorbance. Here, a wavelength of 660 nm is used to measure the transmittance or absorbance using a spectrophotometer, but any wavelength may be used for measurement. Also, one or more CCD cameras and lighting may be installed and the determination may be made from the captured images.

The cutout 24 is provided in the wall having an opaque layer of the liquid paper container 4, which is made of at least laminated paper, and the cutout is sealed with a transparent member 25. However, it is also possible to use not only the side of the liquid paper container 4, but also the straw hole on the top as the cutout 24, sealed with the transparent member 25, and to irradiate light through the cutout 24.

The embodiment of the present invention can be applied not only to the case where the sleeve 3 is supplied to the aseptic filling machine 1 for liquid paper containers, but also to the case where a roll-shaped liquid paper laminate is supplied to the aseptic filling machine for liquid paper containers. For example, a cutout 24 may be provided on the wall surface having an opaque layer of the liquid paper container 4 after molding of a laminate such as polyethylene/paper/polyethylene/aluminum foil/polyethylene, and this cutout 24 may be sealed with a transparent member 25. In this case, after laminating up to polyethylene/paper/polyethylene/aluminum foil, a cutout 24 is provided and a polyethylene layer is provided on the inner surface to obtain a laminate for liquid paper containers for sterility confirmation tests. By supplying the obtained laminate to the aseptic filling machine for liquid paper containers, a liquid medium is filled while molding into the liquid paper container 4, and a sterility confirmation test can be performed. Usually, such a laminate for liquid paper containers is sterilized by immersing it in a bactericide liquid and then drying it. Therefore, there is a high possibility that sterility can be obtained reliably compared to the case where the sleeve 3 is supplied. However, by performing the sterility confirmation test of the present invention, it is possible to determine whether or not it is reliably sterilized.

The liquid paper container 4 of the present invention can be applied not only to the Gabeltop type and brick type liquid paper containers described above, but also to cylindrical and cup-shaped liquid paper containers.

Reference Signs List 1: Aseptic filling machine for liquid paper containers 3: Sleeve 4: Liquid paper container 23: Blank 24: Notch 25: Transparent member

Claims (3)

A liquid paper container is supplied to an aseptic filling machine for liquid paper containers, which sprays a sterilant gas onto the inner surface of the liquid paper container. A notch is provided in a wall surface having an opaque layer of the liquid paper container, which is made of at least laminated paper, and the notch is sealed with a transparent member.
A method for testing sterility confirmation of a liquid paper container aseptically, comprising: filling a liquid paper container for sterility confirmation testing , in which the end of the transparent member is completely heat-sealed to the inner surface of the liquid paper container, with a liquid medium at 1/5 to 4/5 of the volume of the liquid paper container; sealing the liquid paper container, and then vibrating the liquid paper container so that the liquid medium comes into contact with the entire inner surface of the liquid paper container; and culturing the liquid medium and then visually observing the liquid medium through the transparent member. The sterility confirmation test method for a liquid paper container aseptic filling machine according to claim 1 ,
A sterility confirmation test method for a liquid paper container aseptic filling machine, characterized in that light is irradiated onto one of the transparent members of the liquid paper container for sterility confirmation test, in which the cutout portions are provided at two or more opposing locations on the wall surface of the liquid paper container, and the liquid medium is visually observed through the other transparent member. A liquid paper container is supplied to an aseptic filling machine for liquid paper containers, which sprays a sterilant gas onto the inner surface of the liquid paper container. A notch is provided in a wall surface having an opaque layer of the liquid paper container, which is made of at least laminated paper, and the notch is sealed with a transparent member.
A method for testing sterility confirmation of a liquid paper container aseptically, comprising: filling a liquid paper container for sterility confirmation testing , in which the end of the transparent member is completely heat-sealed to the inner surface of the liquid paper container, with a liquid culture medium at 1/5 to 4/5 of the volume of the liquid paper container; sealing the liquid paper container, and then vibrating the liquid paper container so that the liquid culture medium comes into contact with the entire inner surface of the liquid paper container; culturing the liquid culture medium, and then irradiating light from the transparent member and receiving the light with the other transparent member, thereby measuring the transmittance or absorbance.