Method for manufacturing beverage packaged in container with inner bag

Abstract

To provide a method for manufacturing a beverage packaged in a container with an inner bag, by which an oxygen concentration in the inner bag can be sufficiently decreased and filling can be carried out in a short period of time.SOLUTION: A method for manufacturing a beverage packaged in a container with an inner bag is intended to manufacture a beverage packaged in a container with an inner bag in which the beverage D is filled in the inner bag 30 of a container with an inner bag 10, which includes the inner bag 30 and an outer container 20. The method includes: an oxygen sucking step Ax of sucking oxygen Xg from the interior of the inner bag 30; and a beverage filling step Fd of filling the beverage D in the inner bag 30 after the oxygen sucking step Ax.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a method for producing a packed beverage in a container with an inner bag, in which a beverage is filled in the inner bag of a container with an inner bag, the container including an inner bag and an outer container. [Background technology]

[0002] Conventionally, metal barrels have been widely used as containers for transporting and storing beverages such as beer. In conventional beverage dispensing methods using barrels, carbon dioxide is introduced into the barrel to apply pressure to the beverage, thereby dispensing the beverage from the barrel. In response to this, containers with inner bags, such as KeyKeg (manufactured by Lightweight Containers), have come into use in recent years, and development of containers with inner bags is also progressing (see, for example, Patent Document 1). In this type of container with an inner bag, the beverage is dispensed by injecting air between the outer container and the inner bag filled with the beverage and applying pressure to the inner bag from the surroundings. Therefore, the beverage dispensing method using a container with an inner bag has the advantages of not needing carbon dioxide for dispensing and not needing to clean the outer container. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-187495 Summary of the Invention [Problem to be solved by the invention]

[0004] When filling the inner bag of this type of container with an inner bag with a beverage, for example, air is first pumped between the inner bag and the outer container to increase the pressure inside the outer container, and then the inner bag is opened to vent the air (oxygen) inside the inner bag. After that, the beverage is filled into the inner bag while venting the air between the inner bag and the outer container so as to maintain a constant pressure. However, in the above beverage filling method, the air (oxygen) in the inner bag cannot be sufficiently discharged by only one exhaust process, and there is a concern that the quality of the beverage filled in the inner bag may deteriorate. In addition, in the above beverage filling method, in order to reduce the air (oxygen) in the inner bag to an oxygen concentration sufficient to maintain the quality of the beverage, a similar exhaust process must be performed about two to three times, which results in a problem that it takes a long time to fill the inner bag with the beverage.

[0005] Therefore, the present invention has been made with attention to such problems, and its objective is to provide a method for manufacturing a container-packed beverage with an inner bag, which can sufficiently reduce the oxygen concentration in the inner bag and fill the beverage into the inner bag in a short period of time. [Means for solving the problem]

[0006] As a result of extensive research, the inventors have discovered that it is possible to reduce the oxygen concentration inside the inner bag in a short period of time by sucking air out of the inner bag before filling the inner bag with a beverage. That is, in order to solve the above-mentioned problems, a manufacturing method for a packed beverage in a container with an inner bag according to one embodiment of the present invention is a method for manufacturing a packed beverage in a container with an inner bag, in which a beverage is filled in the inner bag of a container with an inner bag, which includes an inner bag and an outer container, and includes an oxygen inhalation process of inhaling oxygen from within the inner bag, and a beverage filling process of filling the inner bag with a beverage after the oxygen inhalation process. Effect of the Invention

[0007] According to the present invention, a packed beverage in a container with an inner bag having a low amount of dissolved oxygen can be produced in a short period of time. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic cross-sectional view illustrating one embodiment of a container with an inner bag used in a manufacturing method for a container-packed beverage with an inner bag according to one aspect of the present invention, in which (a) shows the entire container with an inner bag, (b) shows the outer container, (c) shows the inner bag, and (d) shows the filling lid, each shown in a cross-section along the axis. [Diagram 2]1A to 1E are diagrams illustrating a first embodiment of a method for producing a packed beverage in a container with an inner bag according to one aspect of the present invention. [Diagram 3] 5A to 5E are diagrams illustrating a second embodiment of a method for producing a packed beverage in a container with an inner bag according to one aspect of the present invention. [Figure 4] 1A to 1E are diagrams illustrating a method for producing a packed beverage in a container with an inner bag according to Comparative Example 1. [Diagram 5] 13(a) to (d) are diagrams illustrating a method for producing a packed beverage in a container with an inner bag according to Comparative Example 2. [Figure 6] 13(a) to (e) are diagrams illustrating a method for producing a packed beverage in a container with an inner bag according to Comparative Example 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the drawings are schematic. Therefore, it should be noted that the relationship and ratio between thickness and planar dimensions are different from the actual ones, and the drawings include parts where the relationship and ratio of dimensions are different from each other. Furthermore, the embodiments described below are merely examples of devices and methods for embodying the technical ideas of the present invention, and the technical ideas of the present invention do not limit the materials, shapes, structures, arrangements, etc. of the components to the embodiments described below.

[0010] [Container with inner bag] First, one embodiment of a container with an inner bag used for producing a packaged beverage with an inner bag of each embodiment will be described with reference to FIG. 1(a), the container with inner bag 10 of this embodiment includes an outer container 20, an inner bag 30 contained inside the outer container 20, and a filling lid 40 used for filling and attached so as to cover the upper openings of the outer container 20 and the inner bag 30. The capacity of the container with inner bag 10 can be set to, for example, 3L, 5L, 8L, 10L, etc.

[0011] The outer container 20 of this embodiment is a relatively strong, rigid container made of metal (for example, aluminum), glass, hard plastic, or the like. As shown in FIG. 1(b), the outer container 20 has a disk-shaped (planar) bottom surface 21, a side wall portion 22 extending upward from the periphery of the bottom surface 21 in a hollow cylindrical shape, a truncated cone portion 23 narrowing in diameter upward from the annular upper edge portion of the side wall portion 22, a small-diameter cylindrical portion 24 extending upward from the annular upper edge portion of the truncated cone portion 23, and a flange portion 25 extending laterally in an annular shape from the upper edge portion of the small-diameter cylindrical portion 24.

[0012] As shown in Fig. 1C, the inner bag 30 of this embodiment has a bag body 31 and a cylindrical mouthpiece 32 integrally fixed to an upper opening of the bag body 31. The bag body 31 of this embodiment is configured in a bag shape from a transparent or semi-transparent resin film or the like that has flexibility and gas barrier properties (and light blocking properties), and is formed so that it can be stretched to a tightly fitting shape following the inner surface of the outer container 20 when stretched inside the outer container 20. The mouth part 32 of the inner bag 30 is a relatively robust part made of hard plastic and elastomer (sealing part), etc., and the cylindrical lower end flange part is fixed tightly to the upper opening of the bag body 31, and the necessary sealing function is provided on the outer surface of the flange part. When the inner bag 30 is attached inside the outer container 20, the outer peripheral part corresponding to the inner peripheral surface of the small diameter cylindrical part 24 of the outer container 20 is held in a desired position.

[0013] The filling lid 40 is used only when manufacturing a containerized beverage with an inner bag, and after the beverage is filled, the container with inner bag 10 is removed from the fixed-volume filling device and transferred to a capper, where it is replaced with a distribution lid (not shown). As shown in the same figure (d), the filling lid 40 of this embodiment has a disk-shaped lid main body 41, and the underside of the lid main body 41 is formed with a concave annular portion 44 that can be attached and detached to the flange portion 25 of the outer container 20 by screws. In addition, a filling plug 42 that protrudes upward is provided at the upper central part of the lid body 41, and a connecting plug 43 that protrudes downward at the lower central part of the lid body 41 and is detachably attached to and connectable to the nozzle portion 32 of the inner bag 30.

[0014] The filling plug 42 has a double-tube structure, and is configured such that, when the filling plug 42 is attached, an inner tube portion of the double tube communicates with the inside of the inner bag 30. The filling plug 42 is also configured such that an outer tube portion of the double tube communicates between the outside of the inner bag 30 and the inside of the outer container 20. The upper part of the filling plug 42 is connected via piping to a fixed-volume filling device (not shown) including a well-known filler bowl, and the container 10 with inner bag is set in the fixed-volume filling device. Furthermore, an auxiliary plug 45 is attached to the side of the filling plug 42 on the upper part of the lid main body 41. The auxiliary plug 45 has an on-off valve that can open and close the flow path inside itself. The lower opening of the auxiliary plug 45 is provided so as to communicate between the outside of the inner bag 30 and the inside of the outer container 20. This allows the necessary intake and degassing between the outside of the inner bag 30 and the inside of the outer container 20 through the lower opening of the auxiliary plug 45 at the desired timing.

[0015] [First embodiment (Method A)] Next, a manufacturing method of a packed beverage in a container with an inner bag according to the first embodiment will be described with reference to Fig. 2. The manufacturing method of a packed beverage in a container with an inner bag according to this embodiment is for producing a packed beverage in a container with an inner bag by filling the inside of the inner bag 30 with a beverage D for the container with inner bag 10 including the inner bag 30 and the outer container 20 described above.

[0016] 2(a), the cap portion 32 of the inner bag 30 is attached to the connecting plug 43 of the filling lid 40, and the bag body 31 of the inner bag 30 is inserted into the inside of the outer container 20 from the upper opening of the outer container 20 in a hanging state. Thereafter, the concave annular portion 44 of the lid body 41 is fitted into the flange portion 25 at the upper end of the outer container 20, and the filling lid 40 is attached to the top of the outer container 20 to assemble the container with inner bag 10, and the assembled container with inner bag 10 is set in a fixed-quantity filling device. At this time, as shown in the figure, air (oxygen) Xg is contained in the hanging bag body 31. In contrast, in the first embodiment, as shown in the figure (b), a vacuum pump (not shown) is connected to the inner tube portion 42u of the filling plug 42 having a double tube structure, and the air (oxygen) Xg is sucked from inside the inner bag 30 by the vacuum pump (oxygen suction step Ax). Atmospheric pressure is applied to the outside of the inner bag 30.

[0017] Next, as shown in FIG. 1C, after the oxygen suction step Ax, the filling valve of the quantitative filling device opens, and carbon dioxide (or other inert gas (nitrogen, argon, etc., the same below)) Ng in the filler bowl (product liquid tank) of the quantitative filling device flows into the inner bag 30 of the container 10 with inner bag, filling the inner bag 30 with carbon dioxide (inert gas) Ng and inflating it (inner bag pressure application step Pan). Next, as shown in FIG. 1D, while applying a pressure equivalent to the pressure in the filler bowl (product liquid tank) of the quantitative filling device or the liquid delivery pressure as a counter pressure by the carbon dioxide (inert gas) Ng in the inner bag 30 (inner bag pressure application step Pan), the supply valve for the beverage D on the quantitative filling device side opens, and the beverage D enters the inner bag 30, and the carbon dioxide (inert gas) Ng in the inner bag 30 moves to the filler bowl through the filling valve.

[0018] As a result, as shown in (d) to (e) of the same figure, the beverage D is filled into the inner bag 30 while discharging the carbon dioxide (inert gas) Ng from within the inner bag 30 (beverage filling process Fd). Note that the beverage D is a soft drink or alcoholic beverage (sparkling beverage) containing carbon dioxide gas (carbon dioxide), and is a beer beverage in this embodiment. In the manufacturing method of the first embodiment of the packaged beverage in the inner bag-equipped container, air (oxygen) Xg is sucked from inside the inner bag 30 by a vacuum pump in the oxygen suction process Ax, so that a packaged beverage in the inner bag-equipped container with a small amount of dissolved oxygen Xg can be produced in a short time.

[0019] [Second embodiment (Method B)] Next, a method for producing a packed beverage in a container with an inner bag according to the second embodiment will be described with reference to FIG. First, in the same manner as in the first embodiment, the container 10 with the inner bag is assembled as shown in Fig. 3(a). At this time, air (oxygen) Xg is contained in the inner bag 30. Therefore, in the second embodiment, as in the first embodiment, air (oxygen) Xg is sucked from the inner bag 30 by a vacuum pump as shown in Fig. 3(b) (oxygen suction step Ax). Here, in the above first embodiment, an example was shown in which carbon dioxide (inert gas) Ng is flowed into the inner bag 30 to inflate the inner bag 30 (inner bag pressure application process Pan), and then the carbon dioxide (inert gas) Ng in the inner bag 30 is discharged while filling the inner bag 30 with beverage D (inner bag pressure application process Pan to beverage filling process Fd).

[0020] In contrast, in the second embodiment, a gas Ng such as air or carbon dioxide is filled between the outer container 20 and the inner bag 30, and as a counterpressure, the gas Ng such as air or carbon dioxide is applied within the outer container 20 while being discharged, thereby filling the beverage D into the inner bag 30 (pressure application process Pas within the outer container). That is, in the second embodiment, after the oxygen suction step Ax, as shown in Fig. 2(c), gas (air or gas such as carbon dioxide) is introduced between the outside of the inner bag 30 and the inside of the outer container 20 (inner-container pressure application step Pas). In the example of the second embodiment, air is basically used since it does not come into direct contact with the beverage, and the air is introduced from the auxiliary plug 45.

[0021] Next, the inner tube portion 42u of the filling plug 42 is connected to a filler bowl (not shown) via piping, and as shown in FIG. 1(d), beverage D is filled into the inner bag 30 while applying a pressure equivalent to the pressure in the filler bowl or the liquid delivery pressure as a counterpressure (beverage filling process Fd). Thus, in the second embodiment, in the beverage filling step Fd, the beverage D is filled into the inner bag 30 while applying back pressure by the carbon dioxide (inert gas) Ng in the outer container 20 introduced by the auxiliary plug 45 (outer container internal pressure application step Pas to beverage filling step Fd). As a result, the beverage D is filled into the inner bag 30, as shown in FIG. 1(e). In the manufacturing method of the second embodiment of the containerized beverage with an inner bag, as in the first embodiment described above, air (oxygen) Xg is sucked from inside the inner bag 30 by a vacuum pump in the oxygen suction process Ax, so that a containerized beverage with an inner bag having a low amount of dissolved oxygen Xg can be manufactured in a short time.

[0022] Next, the effects of the method for producing a packed beverage in a container with an inner bag according to the embodiment will be described. As shown in Figures 2 and 3, the first and second embodiments are methods for producing a packed beverage in a container with an inner bag, which include an oxygen inhalation process Ax in which oxygen Xg is inhaled from within the inner bag 30, and a beverage filling process Fd in which a beverage D is filled into the inner bag 30 after the oxygen inhalation process Ax. As a result, according to the manufacturing method of the packed beverage in the container with an inner bag of the first and second embodiments, air (oxygen) Xg is sucked in from inside the inner bag 30 by a vacuum pump in the oxygen suction process Ax, so that a packed beverage in the container with an inner bag having a small amount of dissolved oxygen Xg can be manufactured in a short time [Invention 1 (Methods A and B)].

[0023] In particular, in the first embodiment, after the oxygen suction process Ax from within the inner bag 30, an inner bag pressure application process Pan is included in which an inert gas Ng is flowed into the inner bag 30 to apply a pressure equivalent to the pressure in the filler bowl or the liquid delivery pressure to the inner bag 30, and in the subsequent beverage filling process Fd, the inner bag 30 is filled with beverage D while the inert gas Ng in the inner bag 30 is discharged [Invention 2 (Method A)]. Therefore, the manufacturing method for a packed beverage in a container with an inner bag according to the first embodiment is suitable for filling the inner bag 30 with a carbonated beverage such as beer as the beverage D while preventing or suppressing foaming. Furthermore, in the first embodiment, the beverage D is a beverage containing carbon dioxide, and the inert gas is carbon dioxide, so it is suitable for application to a beer beverage [Invention 3 (Method A)].

[0024] In addition, in the second embodiment, as shown in Figure 3, after the oxygen suction process Ax, a pressure application process Pas within the outer container is included in which gas (air Xg or carbon dioxide Ng) is introduced between the inner bag 30 and the outer container 20 to apply a pressure equivalent to the pressure within the filler bowl or the liquid delivery pressure, and in the beverage filling process Fd, beverage D is filled into the inner bag 30 while discharging the gas between the inner bag 30 and the outer container 20.

[0025] That is, in the second embodiment, in the beverage filling process Fd, the beverage D is filled into the inner bag 30 while applying back pressure by the gas (air Xg or carbon dioxide Ng) inside the outer container 20 (pressure application process Pas inside the outer container), so that, as in the first embodiment, it is possible to produce a containerized beverage with an inner bag having a low amount of dissolved oxygen Xg in a short time while preventing or suppressing foaming of carbonated beverages such as beer [Invention 4 (Method B)]. In particular, in the second embodiment, by using air Xg as the gas in the outer container 20 to apply back pressure, a packed beverage in a container with an inner bag can be produced at a lower cost than when carbon dioxide Ng is used [Invention 5 (Method B)].

[0026] Next, the manufacturing method of the container-packed beverage with inner bag described in the above embodiment will be described based on examples and comparative examples. Here, a container with inner bag 10 including an inner bag 30 and an outer container 20 was prepared with a capacity of 3 liters. In the methods described in the following Examples and Comparative Examples, beer was filled into the inner bag 30 as beverage D, and the time required for filling and the amount of dissolved oxygen in the beverage in the produced beverage packed in the container with inner bag were measured. The amount of dissolved oxygen was measured by sampling beverage D from the container with inner bag 10 and using a gas analyzer (Orbisphere 510 and Orbisphere 31120A manufactured by Hach).

[0027] Example 1 (Method A) Example 1 is an example corresponding to the first embodiment shown in FIG. In Example 1, in the oxygen suction step Ax in the first embodiment, air Xg in the inner bag 30 of the container with inner bag 10 was suctioned by a vacuum pump (-0.06 MPa, 1 s) (Fig. 2(b)). After that, carbon dioxide gas Ng was injected into the inner bag 30, and a pressure equivalent to the pressure in the filler bowl was applied to the inner bag 30 as a counter pressure (Fig. 2(c)). After that, beer beverage was filled into the inner bag 30 as beverage D while discharging the carbon dioxide gas Ng from the inner bag 30 (Figs. 2(d)-(e)).

[0028] Example 2 (Method B) Example 2 is an example corresponding to the second embodiment shown in FIG. In Example 2, in the oxygen suction step Ax in the second embodiment, air Xg in the inner bag 30 of the container 10 with inner bag was suctioned by a vacuum pump (-0.06 MPa, 15 s) (Fig. 3(b)). After that, air Xg was introduced between the inner bag 30 and the outer container 20, and a pressure equivalent to the pressure in a filler bowl (not shown) was applied as a counter pressure (Fig. 3(c)). After that, beer beverage was filled into the inner bag 30 as beverage D while discharging air Xg between the inner bag 30 and the outer container 20 (Figs. 3(d)-(e)).

[0029] Comparative Example 1 (Prior Art) 4(a) to (e) show a method for producing a packed beverage in a container with an inner bag according to Comparative Example 1. In Comparative Example 1, first, as shown in Fig. 1(a), air Xg was injected between the inner bag 30 of the container 10 with an inner bag and the outer container 20 to increase the pressure inside the outer container 20. Next, as shown in Fig. 1(b), the opening of the inner bag 30 was opened to discharge the air Xg inside the inner bag 30. Thereafter, as shown in Fig. 1(c), air Xg was further introduced between the inner bag 30 and the outer container 20, and a pressure equivalent to the pressure in the filler bowl was applied as a counterpressure between the inner bag 30 and the outer container 20. Thereafter, as shown in Figs. 1(d) to (e), beer was filled into the inner bag 30 as beverage D, while the air Xg between the inner bag 30 and the outer container 20 was discharged.

[0030] Comparative Example 2 (Simultaneous Suction and Pressure) 5(a) to (d) show a method for producing a packed beverage in a container with an inner bag according to Comparative Example 2. In Comparative Example 2, starting from the initial installation state (FIG. 1(a)) in the first or second embodiment, as shown in FIG. 1(b), the air Xg in the inner bag 30 of the container 10 with inner bag was sucked out by a vacuum pump (-0.06 MPa, 15 s), and at the same time, air Xg was introduced between the inner bag 30 and the outer container 20, applying a pressure equivalent to the pressure in the filler bowl. After that, as shown in FIG. 1(c)-(d), beer was filled into the inner bag 30 as beverage D while discharging the air Xg between the inner bag 30 and the outer container 20.

[0031] Comparative Example 3 (pressure → suction) 6(a) to (e) show a method for producing a packed beverage in a container with an inner bag according to Comparative Example 3. In Comparative Example 3, as shown in Fig. 1(a), first, air Xg was introduced between the inner bag 30 of the container 10 with an inner bag and the outer container 20 to increase the pressure inside the outer container 20. Next, as shown in Fig. 1(b), the air Xg inside the inner bag 30 was sucked out by a decompression pump (-0.06 MPa, 15 s). Then, as shown in Fig. 1(c), air Xg was further introduced between the inner bag 30 and the outer container 20, and a pressure equivalent to the pressure in the filler bowl was applied as a counter pressure. Then, as shown in Figs. 1(d) to (e), beer was filled into the inner bag 30 while discharging the air Xg between the inner bag 30 and the outer container 20.

[0032] For the above-mentioned Examples 1 and 2 and Comparative Examples 1 to 3, the time required for filling and the amount of dissolved oxygen in the produced beverage D packed in 10 containers with inner pouches are shown in Table 1.

[0033] [Table 1]

[0034] From the results shown in Table 1, it can be seen that in Example 1, although carbon dioxide gas Ng is used, beer beverage can be filled into the inner bag 30 in the shortest time. Furthermore, in Example 1, the amount of dissolved oxygen is also at the lowest level of 128.9 μg / l. Furthermore, in Example 2, although the filling time is at the same level as in Comparative Example 2, it can be seen that the amount of dissolved oxygen can be reduced to the smallest. Thus, the amount of dissolved oxygen in the beverages produced by the above-mentioned first and second embodiments can be reduced to 150 μg / l or less [Invention 6 (Methods A and B)].

[0035] In contrast, it can be seen that the amount of dissolved oxygen is high in all of the manufacturing methods shown in Comparative Examples 1-3. In other words, in order to achieve the same amount of dissolved oxygen as in Examples 1 and 2 using the manufacturing method shown in Comparative Examples 1-3, it is necessary to repeat the operation of discharging air from the inner bag 30 multiple times, which results in a longer filling time than in Examples 1 and 2.

[0036] As explained above based on the embodiments, examples, and comparative examples, the method for producing a packed beverage in a container with an inner bag according to the present invention makes it possible to produce a packed beverage in a container with an inner bag having a low amount of dissolved oxygen in a short period of time. Incidentally, the method for producing a packed beverage in a container with an inner bag according to the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications are possible without departing from the spirit of the present invention. [Explanation of symbols]

[0037] 10 Container with inner bag 20 Outer packaging 30 Inner bag 40 Filling lid D Beverage Xg Air (oxygen) Ng Carbon dioxide (inert gas) Ax Oxygen Inhalation Process Fd beverage filling process Pan inner bag pressure application process Pas Pressure application process inside outer container

Claims

1. A method for producing a container-packed beverage with an inner bag, the method comprising: filling a beverage into an inner bag of a container with an inner bag, the container including an inner bag and an outer container; an oxygen suction step of suctioning oxygen from within the inner bag; and a beverage filling step of filling the inner bag with a beverage after the oxygen inhalation step. A method for producing a packed beverage in a container with an inner bag, comprising:

2. The method includes a step of applying a pressure to the inner bag after the oxygen suction step by injecting an inert gas into the inner bag to apply a counter pressure to the inner bag, The method for producing a packed beverage in a container with an inner bag according to claim 1 , wherein in the beverage filling step, the beverage is filled into the inner bag while discharging the inert gas inside the inner bag.

3. The beverage is a beverage containing carbon dioxide, The method for producing a packed beverage in a container with an inner bag according to claim 2 , wherein the inert gas is carbon dioxide.

4. and a pressure application step in the outer container for applying a counter pressure to the inside of the outer container by introducing a gas between the inner bag and the outer container after the oxygen suction step, The method for producing a packed beverage in a container with an inner bag according to claim 1 , wherein in the beverage filling step, the beverage is filled into the inner bag while discharging gas between the inner bag and the outer container.

5. The method for producing a packed beverage in a container with an inner bag according to claim 4, wherein the gas is air.

6. The method for producing a packed beverage in a container with an inner bag according to claim 1, wherein the amount of dissolved oxygen in the beverage after production is 150 μg / L or less.

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