US20090320415A1

US20090320415A1 - Method for producing packaged drink

Info

Publication number: US20090320415A1
Application number: US12/374,037
Authority: US
Inventors: Katsumi Senbon; Takeshi Iwashita
Original assignee: Toyo Seikan Kaisha Ltd
Current assignee: Toyo Seikan Group Holdings Ltd
Priority date: 2006-07-26
Filing date: 2007-06-08
Publication date: 2009-12-31
Also published as: WO2008012996A1; TW200821256A; KR20090034816A

Abstract

It is intended to provide a process for producing a packaged drink whereby filling can be performed at room temperature without resorting to using a chemical or sterile water, the favorable taste and flavor of the content can be maintained while relieving the thermal degradation thereof, it becomes unnecessary to employ a heat-resistant container or to thermally sterilize or cool after sealing, and thus both of the equipment cost and the running cost can be largely reduced. After thermally sterilizing the content to give a definite sterilization value, it is quickly cooled to room temperature and then stored in a storage tank that has been preliminarily sterilized under such conditions as being equal to or exceeding the thermal sterilization conditions for the contents. While maintaining the storage tank under positive pressure with the use of a sterile gas, the content is fed into a filling machine that has been preliminarily sterilized under such conditions as being equal to or exceeding the thermal sterilization conditions for the contents. Thus, the liquid-feeding system ranging from the storage tank to the filling machine is made a closed liquid-feeding pathway free from the invasion of air from the outside. The drink is filled into a container having been sterilized with hot water in an environment-controlled space isolated from the outside wherein the surroundings have been thermally sterilized and washed with hot water at 65° C. to 100° C.

Description

TECHNICAL FIELD

The present invention relates to a method for producing a packaged drink, in particular a packaged drink such as a packaged tea drink and a packaged acidic drink.

BACKGROUND

Hot pack methods and aseptic methods are conventionally known methods for producing packaged drinks of low acidic drinks such as green tea drinks or the like, or acidic drinks such as drinks with fruit juice or the like that are packaged in, for instance, PET bottles. In hot pack methods, the drink, for instance is thermally sterilized at conditions equal to or exceeding 120° C. and 4 minutes, for low acidic drinks having a pH of 4.6 or higher such as tea drink or the like, and conditions equal to or exceeding 85° C. and 30 minutes for acidic drinks having a pH of 4.6 or lower, the content being then filled, with the liquid temperature kept at 65° C. to 90° C., into washed containers that are then sealed, the containers being sterilized herein by the heat of the content. Thereafter, to sterilize the head space of the containers and the inner surface of the caps, the containers are turned upside down immediately after sealing, and the cap inner surface and so forth are sterilized by coming into contact with the liquid, in what is called overturning sterilization. Simultaneously therewith, hot water is sprayed onto the outer peripheral face of the containers in a pasteurizer, to carry out thereby thermal sterilization at 75° C. over 3 minutes. Thereafter, the containers are cooled down to room temperature (see Patent document 1 for an example of this method).
Hot pack methods are highly problematic in that the content is kept at a high temperature, of 60° C. or above, over a long time, with the content being filled in that state. As a result, the content may undergo thermal deterioration, which may result in rapid loss of taste and flavor. Moreover, the surface of the container is brought into contact with the high-temperature drink during filling, and hence the containers must be heat-resistant, which necessitates a heat resistance treatment in the case of, for instance, PET bottles. Moreover, negative pressure develops in the interior of the containers after cooling, and thus the containers must be made thick-walled so as to ensure sufficient strength to withstand that negative pressure. The foregoing drives up thus the cost of the containers, which is a drawback. In terms of equipment, hot pack methods suffer the drawback of increased equipment space and higher equipment costs brought about by the need for large-scale pasteurizers for post-sterilization and cooling. From the viewpoint of running costs, pasteurizers are also problematic in that they require large amounts hot water, which entails greater water consumption and higher energy costs.
In aseptic filling, meanwhile, the drink, which has been sterilized beforehand at high temperature for a short time using a means such as a heat exchanger or the like, followed by cooling, is sterilized with a chemical agent such as hydrogen peroxide, peracetic acid or the like. The drink is filled and sealed then, at room temperature and in an aseptic environment, into containers which need not be heat resistant and that have been washed with aseptic water. This method can ensure sealing in wholly aseptic conditions, and hence the method is adequate for filling, even at room temperature, not only acidic drinks or tea but also milk-containing drinks in which spore-forming bacteria, such as Clostridium botulinum or the like, proliferate readily. Although aseptic filling is thus advantageous in that it entails little thermal deterioration of contents, it requires a sterilizing chemical agent and a chemical agent treatment device for sterilizing the containers. Aseptic filling requires also, for instance, large amounts of aseptic water and a washing device for washing the containers. Aseptic filling is thus a large-scale operation involving various equipment for carrying out the above steps, as well as a clean room and ancillary controls. The method is hence problematic in terms of the substantial equipment cost and running costs associated therewith.
Therefore, the inventors proposed (Patent document 2) a novel hot pack method as a method for solving the above problems of conventional hot pack methods and aseptic filling methods. This novel method involved thermally sterilizing a green tea drink comprising 30 mg % or more of catechins at a pH of 4.6 or higher or an acidic drink having a pH below 4.6; keeping thereafter the drink at a temperature of 60° C. to 70° C.; thermally sterilizing and washing at least the inner surface of a container with worm water at 65° C. to 100° C.; filling the drink into the sterilized container, at a filling temperature of 60° C. to 70° C., in an environment-controlled space, isolated from the outside, in which the filling and sealing devices and the surrounding environment thereof are thermally sterilized and washed beforehand with worm water at 65° C. to 100° C.; and cooling, after sealing, down to room temperature not higher than 40° C.
This method does not require a post-sterilization step after filling and sealing, and hence no large-scale equipment in the form of pasteurizers need be employed. The method is advantageous in allowing reducing equipment costs and running costs as compared with conventional hot pack methods, and in allowing easing the conditions relating to container resistance against vacuum deformation. The method, however, is problematic in that it requires a cooling step after sealing, and results in loss of taste and/or flavor, brought about by content thermal deterioration, although to a lesser extent than in conventional hot pack methods. Also, the method cannot obviate the need for the containers to be resistant to vacuum deformation.
Patent document 1: Japanese Unexamined Patent Application Laid-open No. 2001-278225 “Producing method of beverage bottle”, Oct. 10, 2001
Patent document 2: Japanese Unexamined Patent Application Laid-open No. 2006-69624 “Method for producing a packaged drink”, Mar. 16, 2006

DISCLOSURE OF THE INVENTION

Problem to be Solved by the Invention

Lowering the filling temperature is an effective way of solving the above-described shortcomings of conventional hot pack methods. Once the content is cooled to room temperature after sterilization, however, microbial contamination remains a possibility on account of small parts such as liquid-feeding pumps, packings, joints and so forth, in the liquid-feeding system from the storage tank to the filling machine, that are ordinarily used in filling equipment, while from the viewpoint of product safety, it has not been possible heretofore to lower the filling temperature below that in the above-described prior art documents.
With a view to further improving the proposed filling systems above, it is an object of the present invention to provide a method for producing a packaged drink, comprising a novel filling and sealing system, that permits room temperature filling and allows maintaining good taste and flavor by mitigating thermal deterioration of the content, that does not require using a heat-resistant container, that does not require thermal sterilization or cooling after sealing, and that does not require using a chemical agent or sterile water, as in aseptic filling methods, to afford as a result substantial savings in equipment costs and running costs.
It is a further object of the present invention to provide a method for producing a packaged drink, comprising a novel filling and sealing system, that permits room temperature filling and allows maintaining good taste and flavor by mitigating thermal deterioration of the content, that does not require using a heat-resistant container, that does not require thermal sterilization or cooling after sealing, and that does not require using a chemical agent or large amounts of sterile water, as in aseptic filling methods, to afford as a result substantial savings in equipment costs and running costs.

Means for Solving the Problems

In order to attain the above goal, and as a result of diligent research and experimentation, the inventors perfected the present invention upon finding that content sterilization by chemical agent becomes unnecessary, and that the content can be filled at room temperature through quick cooling after quick thermal sterilization, by restricting the content drink to drinks in which growth of spore-forming bacteria is difficult after heating, for instance a tea drink such as Oolong tea or green tea comprising 30 mg % or more of catechins at a pH of 4.6 or higher, and an acidic drink having a pH below 4.6, and upon finding that content sterilization by chemical agent becomes unnecessary, and that the content can be filled at room temperature through quick cooling after quick thermal sterilization, by making the liquid-feeding pathway of the content liquid, from thermal sterilization of the content to filling thereof, into a sterilized wholly closed space, and by maintaining a clean environment, isolated from the outside, in which containers and the filling and sealing environment are sterilized with worm water.
Specifically, the method for producing a packaged drink of the present invention, which achieves the above goal, comprises the steps of thermally sterilizing and washing beforehand, using worm water at 65° C. to 100° C. or a chemical agent, a surrounding environment where a container and a cap are sterilized, washed, filled and sealed; thermally sterilizing and washing beforehand a liquid-feeding pathway, up to a cooling device, a storage tank and a filling machine, under conditions equal to or exceeding the thermal sterilization conditions of a drink to be filled; and thermally sterilizing and washing at least the inner surface of the container and cap with hot water at 65° C. to 100° C., wherein the drink to be filled is thermally sterilized up to a predetermined sterilization value and is thereafter quickly cooled to room temperature, the cooled drink being stored in the storage tank, and wherein a content liquid is fed to the filling machine to make the liquid-feeding pathway into a closed liquid-feeding pathway into which outer air does not intrude, and the surrounding environment is made an environment-controlled space isolated from the outside, such that the drink is filled at room temperature into the sterilized container and then sealed in the environment-controlled space.
Another invention of the present application is the above method for producing a packaged drink, wherein the drink is a drink comprising 30 mg % or more of catechins at a pH of 4.6 or higher, and the drink is thermally sterilized to a sterilization value equal to or higher than that of thermal sterilization at 135° C. and 7.58 seconds.
Another invention of the present application is the above method for producing a packaged drink, wherein the drink is an acidic drink having a pH below 4.6, and the drink is thermally sterilized to a sterilization value equal to or higher than that of thermal sterilization at 85° C. and 30 minutes.
Another invention of the present application is any of the above methods for producing a packaged drink, wherein the environment-controlled space is a space housed in a box.
A further invention of the present application is characterized in that the storage tank is kept at positive pressure with sterile gas, and the liquid is fed from the storage tank to the filling machine through pressure-feeding by sterile gas.
Another invention of the present application is the above method for producing a packaged drink, wherein washing which is performed after thermal sterilization and washing of the surrounding environment using a chemical agent has also a sterilizing function by using hot water at 65° C. to 100° C.
Another invention of the present application is the above method for producing a packaged drink, wherein any of a peracetic acid chemical agent, hydrogen peroxide, an ozone-based chemical agent, and a chlorine-based disinfectant containing hypochlorous acid is used as the chemical agent for sterilizing and washing beforehand the surrounding environment where a container and a cap are sterilized, washed, filled and sealed.

EFFECTS OF THE INVENTION

The method for producing a packaged drink of the present invention enables room-temperature filling of, for instance, acidic drinks such as fruit juice drinks, as well as tea- or milk-containing drinks or the like, without the need for containers, equipment and the environment to be sterilized with a chemical agent solution or washed with sterile water, as is the case in aseptic filling methods. The invention allows thus obtaining a good packaged drink, as afforded by aseptic filling methods, without flavor loss due to content thermal deterioration, which occurs in hot pack methods. The method of the present invention, moreover, resorts to simpler equipment than aseptic filling, and uses no chemical agent solution. Hence, the method of the present invention affords substantial savings in equipment costs and running costs while increasing the efficiency and speed of the production line. In the method of the present invention, the containers need not be heat-resistant or resistant to vacuum deformation, and thus the walls of the containers may be thinner, which allows reducing container costs. The method of the present invention, moreover, requires no post-sterilization or cooling after sealing, and hence equipment is simpler than in hot pack methods. The method of the present invention requires no large amounts hot water, and allows thus reducing equipment and running costs while increasing line speed. The products, moreover, can move onto inspection, box packing and so forth immediately after filling and sealing, which allows increasing line efficiency while achieving energy savings.
In the method for producing a packaged drink of the present invention, in which a surrounding environment is thermally sterilized and washed using a chemical agent, the use of chemical agent is restricted, in the case of acidic drinks such as fruit juice drinks, as well as tea- or milk-containing drinks or the like, to the step of sterilizing and washing the surrounding environment, in which the containers are washed, filled and sealed, that is carried out prior to filling. Hence, room temperature filling becomes possible without the need for large amounts of chemical agent solution, sterile water and so forth, as is the case in aseptic filling. The method of the present invention allows thus obtaining a good packaged drink, as afforded by aseptic filling methods, with little flavor loss due to content thermal deterioration, which occurs in hot pack methods.
Also, less chemical agent and washing liquid need be used, compared to aseptic filling, and hence equipment can be scaled down in proportion. The method of the present invention, moreover, requires no post-sterilization or cooling after sealing, and hence equipment is simpler than in hot pack methods. This affords, as a result, substantial savings in equipment costs and running costs.
In the method for producing a packaged drink of the present invention, the drink is thermally sterilized to a sterilization value equal to or higher than that of thermal sterilization at 135° C. and 7.58 seconds, when the drink is a drink comprising 30 mg % or more of catechins at a pH of 4.6 or higher. However, the drink is quickly cooled down to room temperature after sterilization, and therefore, the method of the present invention allows mitigating thermal deterioration and preserving flavor, in addition to the above effects. In a tea drink comprising 30 mg % or more of catechins at a pH of 4.6 or higher, the environment after filling and sealing is an environment where spore-forming bacteria cannot survive, and hence sterilizing and washing the containers with hot water prior to drink filling does away with the need for sterilization after filling using a pasteurizer.
When in the method for producing a packaged drink of the present invention the drink is an acidic drink having a pH below 4.6, thermally sterilizing the acidic drink to a sterilization value identical to or higher than 85° C. and 30 minutes allows inhibiting bacterial growth after sealing, besides the above effects. Also, the drink is quickly cooled after thermal sterilization, which allows preventing flavor and component deterioration. Moreover, sterilizing and washing the container with hot water prior to drink filling does away with the need for sterilization after filling using a pasteurizer.
In the method for producing a packaged drink of the present invention, besides the above effects, making the environment-controlled space where the containers are sterilized with hot water, the content is filled and the containers are sealed, into a space housed in a box, has the effect of isolating that space from the outside, which allows preventing contamination from outside.
In the method for producing a packaged drink of the present invention, besides the above effects, liquid can be feed without using pumps, in which small parts are difficult to sterilize, by pressure-feeding the liquid from the storage tank into the filling machine by means of sterile gas. This facilitates sterilization of the liquid-feeding mechanism, while positive pressurization allows preventing outer air from intruding into the path, which allays the concern of the drink being contaminated with outer air.
In the method for producing the different packaged drinks of the present invention, besides the above effects, hot water has also a sterilizing function, when used at 65° C. to 100° C. for washing the surrounding environment, after sterilization thereof with a chemical agent. As a result, this allows the chemical agent to be used at a lower temperature than is the case in, for instance, aseptic filling, and allows curbing thereby breakdown of the chemical agent, and increasing the number of times that the chemical agent can be reused, while reducing damage inflicted on the equipment. The sterilizing effect against heat-resistant spore-forming bacteria is also enhanced.
In the present invention, the surrounding environment, in which containers and caps are sterilized, washed, filled and sealed, is sterilized and washed beforehand using a specific chemical agent. A yet more reliable sterilizing effect is achieved thereby.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a producing system for realizing the method for producing a packaged drink according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating an embodiment of the method for producing a packaged drink according to the present invention.

FIG. 3 is a diagram for explaining the sterilizing and washing method of the present invention, using a chemical agent in a clean box that becomes an environment-controlled space.

FIG. 4 is a flowchart illustrating another embodiment of the method for producing a packaged drink according to the present invention.

EXPLANATION OF REFERENCE NUMERALS

- 1 chemical agent tank
- 3 drain tank
- 10 bottle sterilizing and washing device
- 12 capper
- 15 clean box
- 17 fixed hot water spraying nozzles
- 21 balance tank
- 23 quick cooling device
- 26 head tank
- 2 hot water tank
- 4, 5 selector valves
- 11 filling machine
- 14 environment-controlled space
- 16 rotary hot water spraying nozzles
- 20 preparation tank
- 22 high-temperature short-time sterilizer
- 25 storage tank

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention are explained below with reference to accompanying drawings.
The drinks for which the present invention is suitable are, for instance, green tea, Oolong tea or the like comprising 30 mg % or more of catechins at a pH of 4.6 or higher, or acidic drinks having a pH below 4.6. Examples of the acidic drink include, for instance, natural juice, juice drinks, soft drinks containing juice, fruit drinks containing fruit grains, lemonade, sports drinks and the like.
The containers used in the method the present invention are, for instance, polyester bottles such as a PET bottle, and also polyester cups, plastic containers, for instance polyester containers such as trays or the like, glass bottles, metal bottles, food cans or the like. Given that the present invention eases the conditions relating to vacuum resistance of PET bottles, the present invention is particularly suitable for the manufacture of the above-described drinks packaged in PET bottles, in terms of reducing wall thickness.
In the method for producing a packaged drink in an embodiment of the present invention, the content drink is thermally sterilized, by high-temperature short-time sterilization, up to a predefined sterilization value. Thereafter, the drink is immediately quick-cooled down to room temperature (15° C. to 40° C.), and is stored in a storage tank that has been sterilized and washed beforehand under conditions equal to or exceeding the thermal sterilization conditions of the drink. In the present invention, at least the wet surfaces of all equipment, such as the storage tank and so forth, are thermally sterilized beforehand, with steam or hot water, to a sterilization value equal to or higher than the sterilization value of the content drink. Also, at least the inner face of the containers, as well as the outer surface of the equipment and the space environment in which container sterilization, washing, filling and sealing are carried out, are thermally sterilized and washed with hot water at 65° C. to 100° C. The controlled space is herein this space environment isolated from the outside environment. The cooled drink is stored in the storage tank, whereupon the content liquid is fed into the filling machine while keeping the storage tank at a positive pressure with sterile gas, to make thereby the above-described liquid-feeding pathway into a closed liquid-feeding pathway into which outer air does not intrude. The drink in the sterilized environment-controlled space, isolated from the outside, is then filled at room temperature into the sterilized containers, and the containers are sealed. After sealing, the containers can move on directly, in that state, to inspection and box packing, without having to be cooled or heated.
In the case of the above-described tea drink comprising 30 mg % or more of catechins at a pH of 4.6 or higher, the content drink, i.e. the tea drink is subjected to high-temperature short-time sterilization in such a way so as to obtain a sterilization value equal to or higher than 135° C. and 7.58 seconds. The inventors studied the antimicrobial effect elicited by catechins vis-à-vis various microorganisms in drinks containing 15 mg % to 50 mg % of catechins. The results are given in Table 1. In the table, O denotes observed antimicrobial effect, Δ denotes observed or unobserved antimicrobial effect, depending on microorganism type, and x denotes no antimicrobial effect observed.

	TABLE 1

	Catechin amount (content product)

	50 mg %	38 mg %	27 mg %	15 mg %
Microorganism	(Green tea)	(Oolong tea)	(Tea blend)	(Tea blend)

Spore-forming	∘	∘	Δ	Δ
bacteria
Non spore-	Δ	Δ	Δ	Δ
forming
bacteria
Molds	x	x	x	x
Yeasts	x	x	x	x

Table 1 is shows that for tea drinks having a catechin content of 27 mg %, the antimicrobial effect was observed for most spore-forming bacteria, although the effect was weak for some spore-forming bacteria. These results indicate that, in terms of safety, the tea drinks for which the invention is suitable are tea drinks comprising 30 mg % or more of catechins. For some non spore-forming bacteria, as well as molds and yeasts, catechins exhibit no antimicrobial effect. These microorganisms can be eliminated by low-temperature heating. The invention affords thus an antimicrobial effect against spore-forming bacteria for tea drinks containing 30 mg % or more of catechins, and allays therefore any concerns as regards drink deterioration, regardless of the tea drink. When the drink is the above acidic drink having a pH below 4.6, the drink is thermally sterilized at high temperature over a short time so as to obtain a sterilization value equal to or greater than 85° C. and 30 minutes.
A typical example, in which the above drinks are filled into PET bottles, is explained below with reference to the schematic diagram of a producing line illustrated in FIG. 1 and the flowchart illustrated in FIG. 2.
In the packaged drink production line of the present embodiment illustrated in FIG. 1, a bottle sterilizing and washing device 10, a filling machine 11, a capper 12 and a cap sterilizing and washing device (not shown) are disposed in a clean box 15 that makes up an environment-controlled space 14. In the present invention, “environment-controlled space” denotes a space isolated from the outside and in which the filling and sealing equipment and the surrounding environment thereof have been thermally sterilized and washed beforehand with hot water at 65° C. to 100° C. Sterile air is supplied to the interior of the space, which is kept at a positive pressure vis-à-vis the exterior environment, in such a manner that outer air does not flow readily into the space. Sterilization and washing of the surrounding environment is carried out before starting the production of the packaged drink. As illustrated in FIG. 1, in the clean box 15 there are appropriately disposed rotary hot water spraying nozzles 16, as well as fixed hot water spraying nozzles 17 for intensively spraying hot water towards the portions of the bottle sterilizing and washing device 10, the filling machine 11 and the capper 12 that come into contact with the containers. The method disclosed in Patent document 2 can be appropriately employed as the method for sterilizing and washing the surrounding environment, and hence a detailed explanation thereof will be omitted herein.
In the present embodiment, there are thermally sterilized at least the inner surface of the bottles fed to the bottle sterilizing and washing device 10 in the environment-controlled space 14 by a bottle supply device located outside the environment-controlled space. The inner surface of the bottles is preferably thermally sterilized with hot water at 65° C. to 100° C. The sterilization time ranges from 3 to 10 seconds. In this method, sterilization of the bottles by hot water and subsequent washing of the bottles are performed simultaneously, and hence there is no need for a separate washing operation of the bottles after sterilization. Similarly, caps are supplied by a cap supply device, located outside the environment-controlled space, to a cap sterilizing and washing device disposed in the controlled space, such that the inner and outer surfaces of the caps are thermally sterilized through spraying of hot water at 65° C. to 100° C.
The inner and outer surfaces of the bottles can be sterilized with hot water, for instance, by placing the bottles, upside down, in a bottle washing device, and by spraying hot water onto the bottles out of hot water spraying nozzles. Similarly, the inner and outer faces of the caps can be sterilized with hot water by spraying hot water, from hot water spraying nozzles, onto the inner and outer surface of the caps that move, for instance, through a wire chute, or that move downwards through an opening of a turret. Once sterilized and washed, the bottles are supplied to the filling machine 11, where they are filled with the drink. The caps are supplied to the capper 12, and the bottles filled with drink are capped and sealed.
As illustrated in FIG. 1, the drink, as the content liquid, is prepared in a preparation tank 20 disposed outside the clean box, is then stored in a balance tank 21, and is supplied to a high-temperature short-time sterilizer 22 and a quick cooling device 23, where high-temperature short-time sterilization and quick cooling are carried out.
High-temperature short-time sterilization denotes thermal sterilization by, for instance, HTST sterilization or the like. When the drink is the above-described tea drink comprising 30 mg % or more of catechins at a pH of 4.6 or higher, high-temperature short-time sterilization is carried out in the present embodiment in such a way so as to obtain a sterilization value equal to or higher than 135° C. and 7.58 seconds. When the drink is the above acidic drink having a pH below 4.6, the drink is thermally sterilized over a short time, for instance at 93 to 95° C., so as to obtain a sterilization value equal to or greater than 85° C. and 30 minutes.
The drink, having been subjected to high-temperature short-time sterilization, passes next through the quick cooling device 23, where it is subjected to quick cooling over a short time, down to room temperature, by heat exchange with a coolant while passing through the quick cooling device 23. Although about 35° C. is a suitable room temperature, the latter can range from 15° C. to 40° C. depending on, for instance, drink type, season and so forth. The drink, having been quick cooled, is stored in a storage tank 25 comprising an aseptic tank. The storage tank 25, the quick cooling device 23, a below-described head tank 26, the filling machine 11, as well as all the wet surfaces of piping and so forth in contact with the foregoing, form a closed pathway that is sterilized beforehand through sterilization and washing with steam or hot water in such a way so as to achieve sterilization conditions equal to or exceeding the sterilization conditions of the drink to be filled, i.e. sterilization conditions equal to or exceeding 135° C. and 7.58 seconds. In particular, intrusion of outer air into the storage tank 25 is prevented by keeping a positive pressure with a sterile gas. Also, the stored drink is fed from the storage tank to the filling machine, via the head tank 26, by being pressure-fed with sterile gas. As a result, liquid feeding can be achieved without resorting to any pumps, which are hard to sterilize and which, for structural reasons, do not easily afford complete sterilization and sealing. Moreover, the drink can be kept in a sterile condition even at room temperature. The head tank 26 as well is formed to be totally sealed. The drink stored in the head tank 26 is fed into the filling machine through pressure-feeding with sterile gas, to be filled into bottles in an aseptic environment-controlled space.
The bottles filled with the drink are conveyed from the filling machine to the capper 12, provided in the environment-controlled space, where the bottles are completely sealed with caps supplied from a cap supply device, disposed outside the environment-controlled space, and sterilized and washed under the same conditions as the bottles in the cap sterilizing and washing device disposed in the environment-controlled space. After being sealed, the bottles can move directly onwards to product inspection, box packing or the like, without having to being subjected to post-processing such as post-sterilization, cooling or the like by passing through a pasteurizer and/or cooler, as in conventional hot pack methods.
FIG. 3 is a diagram for explaining the method of the present invention for sterilizing and washing a clean box, which becomes an environment-controlled space, using a chemical agent, and FIG. 4 is a flowchart of the method for producing a packaged drink according to the present invention. A method for producing a packaged drink in another embodiment of the present invention is carried out in accordance with the steps of the flowchart of FIG. 4. In the figures, the black triangular arrows denote flow along the production line, while simple arrows indicate the process. In the method for producing a packaged drink in an embodiment of the present invention, the sterilizing and washing treatment enclosed by the dot-dashed line in FIG. 4 is carried out prior to the operation in a line 1, in which the content drink is thermally sterilized by high-temperature short-time sterilization up to a predefined sterilization value, whereafter the drink is immediately quick-cooled down to room temperature (15° C. to 40° C.), and is stored in a storage tank, and prior to the operation in a line 2, in which the drink is filled and sealed into bottles. In a preliminary treatment, the quick cooling device 23, the storage tank 25 and the head tank 26 are sterilized and washed with steam or hot water under conditions equal to or exceeding the thermal sterilization conditions of the drink. The space environment in which container sterilization, washing, filling and sealing are carried out is a controlled space isolated from the outside. This space is sterilized with a chemical agent and washed prior to drink filling. Also, at least the inner surface of the used containers and caps are thermally sterilized and washed with hot water at 65° C. to 100° C. The cooled drink is stored in the storage tank, and then the content liquid is fed into the filling machine while keeping the storage tank at a positive pressure with sterile gas, to make thereby the above-described liquid-feeding pathway into a closed liquid-feeding pathway (region enclosed by a broken line in FIG. 4) into which outer air does not intrude. The drink in the sterilized environment-controlled space, isolated from the outside, is then filled at room temperature into the sterilized containers, and the containers are sealed. After sealing, the containers can move on directly, in that state, to inspection and box packing, without having to be cooled or heated.
An explanation follows next, with reference to the system diagram of FIG. 3, on the sterilizing and washing method of the present invention, using a chemical agent in the clean box 15 as the environment-controlled space 14. In the figure, the reference numeral 1 denotes a chemical agent tank, 2 denotes a hot water tank, 3 denotes a drain tank, the reference numerals 4, 5 and 6 denote valves for flow path switching, 7 denotes a chemical agent supply pipe, and 8 a hot water supply pipe. The selector valves 4, 5 and 6 are initially set as illustrated in the figure. When pressure-fed out of the chemical agent tank 1, the chemical agent passes through the supply pipe 7 and reaches the various rotary spraying nozzles 16 and fixed spraying nozzles 17 of the clean box 15, whereupon the chemical agent is sprayed in the clean box 15 out of the rotary spraying nozzles 16 and the fixed spraying nozzles 17. The environment-controlled space 14 is sterilized thus through the action of the sprayed chemical agent. The sprayed chemical agent flows down to the floor, inside the chamber, and flows out of the latter via drain pipes. At this time, the selector valves 5 are in the state illustrated in the figure, and thus the chemical agent flows towards the right in the figure. Although the drain tank 3 is disposed on the right side, the opening/closing valve 6 is blocking herein flow into the drain tank 3, as illustrated in the figure, and hence the chemical agent is recirculated towards the chemical agent tank 1. The chemical agent employed is not discarded after a single use, and can be used repeatedly as long as the sterilizing functionality thereof can be ensured. The chemical agent is strongly acidic, and thus must be subjected to a reducing treatment or pH adjustment treatment as a wastewater treatment after use.
Once the sterilization treatment is over, the selector valves 4 are switched so as to shut off the chemical agent supply pipe 7 and open the hot water supply pipe 8, whereupon the selector valve 6 is set to open flow to the drain tank 3. The hot water from the hot water tank 2 passes now through the hot water supply pipe 8 and reaches the various rotary hot spraying nozzles 16 and fixed spraying nozzles 17 of the clean box 15, whereupon the chemical agent is sprayed in the clean box 15 out of the rotary spraying nozzles 16 and the fixed spraying nozzles 17. The sprayed hot water washes the chemical agent remaining in the clean box 15. The hot water used for washing flows down to the floor, inside the chamber, and flows out of the latter via drain pipes. At this time, the selector valves 5 are in the state illustrated in the figure, and thus the hot water is drained towards the right in the figure. The selector valve 6 blocks now flow to the chemical agent tank 1 and opens flow to the drain tank 3, and hence the washing water flows into the drain tank 3. Sterilization by chemical agent and washing of the environment-controlled space 14 in the clean box 15 are over after the above operations. The selector valves 5 are then switched so as to open flow to the hot water tank 2 on the left of the figure, in preparation for the next operation. The treatment amount of washing water and so forth in one filling and sealing operation depends on the scale of the equipment, but ranges from 2 to 3 t. In the present invention there is no large outflow of waste water, unlike in aseptic filling systems where 20 t/hour of waste water are generated including container washing, and thus the waste water can be batch-treated by accumulating in the drain tank 3. The environment-controlled space can be chemically sterilized by producing lot units, or, for instance, once every 2 or 3 lots.
When using a peracetic acid agent as the chemical agent, sterilization requires 3 minutes at 40° C. Taking the resulting deterioration rate as 1, sterilization using the chemical agent at 50° C. requires only 1 minute, but to a deterioration rate of 1.5. At 60° C., sterilization needs only 10 seconds, to a deterioration rate of 4. That is, the increase in decomposition rate means that less chemical agent is conserved as the number of times that the chemical agent can be re-used decreases in proportion to the increase in the decomposition rate. A relationship holds herein in which a higher use temperature results in an enhanced antimicrobial effect but in reduced chemical agent conservation. The antimicrobial effect of hot water is brought out when, as described above, hot water at 60° C. to 100° C. is used for washing after using the chemical agent. Hence, chemical agent conservation can be improved in proportion to the extent by which the usage temperature of the chemical agent can be lowered.
At high temperatures, the chemical agent is problematic in that it deteriorates components and inflicts damage on equipment.
In the present invention, the clean box is sterilized with a chemical agent, and hence washing after the sterilization treatment may involve simply washing with sterile water, without using the above-described hot water, depending on the used chemical agent and the concentration thereof. In this case, the selector valves 4 used must be modified into a three-way valve that can also connect with a sterile water tank.
Also, washing may be unnecessary, depending on the chemical agent used, for instance ozone-based chemical agents.
In the present embodiment there is thermally sterilized at least the inner surface of the bottles that are fed to the bottle sterilizing and washing device 10, in the environment-controlled space 14, by a bottle supply device located outside the environment-controlled space. The inner surface of the bottles is preferably thermally sterilized with hot water at 65° C. to 100° C. The sterilization time ranges from 3 to 10 seconds. In this method, sterilization of the bottles by hot water and subsequent washing of the bottles are performed simultaneously, and hence there is no need for a separate washing operation of the bottles after sterilization. Rinsing with sterile water may also be carried out with a view to washing away germs adhered to the bottles and/or preventing deformation of lighter containers. Similarly, caps are supplied by a cap supply device, located outside the environment-controlled space, to a cap sterilizing and washing device disposed in the controlled space, such that the inner and outer surfaces of the caps are thermally sterilized through spraying of hot water at 65° C. to 100° C.
The inner and outer surfaces of the bottles can be sterilized with hot water, for instance, by placing the bottles, upside down, in a bottle washing device, and by spraying hot water onto the bottles out of hot water spraying nozzles. Similarly, the inner and outer faces of the caps can be sterilized with hot water by spraying hot water, from hot water spraying nozzles, onto the inner and outer surface of the caps that move, for instance, through a wire chute, or that move downwards through an opening of a turret. Once sterilized and washed, the bottles are supplied to the filling machine 11, where they are filled with the drink. The caps are supplied to the capper 12, and the bottles filled with drink are capped and sealed.
In the operation of the line 2, where the drink is filled and sealed into the bottles, thermal sterilization is carried out by spraying hot water onto the containers before filling. Herein, the selector valve 5 from the bottle sterilizing and washing device in FIG. 3 is set toward the left in the figure, i.e. is set to communicate with the hot water tank 2. Therefore, the process water is recirculated into the hot water tank 2, to be reused. The bottles carried in from outside into the environment-controlled space 14 having been sterilized beforehand with the chemical agent are ordinarily clean. Even if some germs had become adhered to the bottles, the latter are subjected herein to a sterilizing and washing treatment. As a result, the process water is virtually uncontaminated and can hence be reused, which contributes to reducing the amount of waste water. The caps carried in from outside are not as clean as the bottles, and hence the selector valve 5 is set toward the right in the figure, i.e. communicating with the drain tank 3, so that the process water from the capping chamber, in which the caps are sterilized and washed, flows into the drain tank 3, where it cannot be reused. The process amount of washing water and so forth in one filling and sealing operation is the sum of the above chemical agent washing water and the process water used for sterilizing and washing the caps.
As illustrated in FIG. 1, the drink, as the content liquid, is prepared in a preparation tank 20 disposed outside the clean box, is then stored in a balance tank 21, and is supplied to a high-temperature short-time sterilizer 22 and a quick cooling device 23, where high-temperature short-time sterilization and quick cooling are carried out.
High-temperature short-time sterilization denotes thermal sterilization by, for instance, HTST sterilization or the like. When the drink is the above-described tea drink comprising 30 mg % or more of catechins at a pH of 4.6 or higher, high-temperature short-time sterilization is carried out in the present embodiment in such a way so as to obtain a sterilization value equal to or higher than 135° C. and 7.58 seconds. When the drink is the above acidic drink having a pH below 4.6, the drink is thermally sterilized over a short time, for instance at 93 to 95° C., so as to obtain a sterilization value equal to or greater than 85° C. and 30 minutes.
The drink, having been subjected to high-temperature short-time sterilization, passes next through the quick cooling device 23, where it is subjected to quick cooling over a short time, down to room temperature, by heat exchange with a coolant while passing through the quick cooling device 23. Although about 35° C. is a suitable room temperature, the latter can range from 15° C. to 40° C. depending on, for instance, drink type, season and so forth. The drink, having been quick cooled, is stored in a storage tank 25 comprising an aseptic tank. The storage tank 25, the quick cooling device 23, a below-described head tank 26, the filling machine 11, as well as all the wet surfaces of piping and so forth in contact with the foregoing, form a closed pathway that is sterilized beforehand through sterilization and washing with steam or hot water in such a way so as to achieve sterilization conditions equal to or exceeding the sterilization conditions of the drink to be filled, i.e. sterilization conditions equal to or exceeding 135° C. and 7.58 seconds. In particular, intrusion of outer air into the storage tank 25 is prevented by keeping a positive pressure with a sterile gas. Also, the stored drink is fed from the storage tank to the filling machine, via the head tank 26, by being pressure-fed with sterile gas. As a result, feeding of liquid can be achieved without resorting to any pumps, which are hard to sterilize and which, for structural reasons, do not easily afford complete sterilization and sealing. Moreover, the drink can be kept in a sterile condition even at room temperature. The head tank 26 as well is formed to be totally sealed. The drink stored in the head tank 26 is fed into the filling machine through pressure-feeding with sterile gas, to be filled into bottles in an aseptic environment-controlled space.
The bottles filled with the drink are conveyed from the filling machine to the capper 12, provided in the environment-controlled space, where the bottles are completely sealed with caps supplied from a cap supply device, disposed outside the environment-controlled space, and sterilized and washed under the same conditions as the bottles in the cap sterilizing and washing device disposed in the environment-controlled space. After being sealed, the bottles can move directly onwards to product inspection, box packing or the like, without having to being subjected to post-processing such as post-sterilization, cooling or the like by passing through a pasteurizer and/or cooler, as in conventional hot pack methods.

EXAMPLES

Example 1

A green tea drink (pH 5.9, catechin content 52 mg %) was produced using the above-described equipment and producing method, employing PET bottles having a 2 L capacity.
Specifically, a green tea drink having been thermally sterilized at high temperature for a short time, at 135° C. over 30 seconds, followed by rapid cooling to room temperature, was stored in a storage tank kept at a positive pressure with sterile gas and having been sterilized and washed beforehand to a sterilization value equal to or greater than the sterilization value of the content. Thereafter, the drink was pressure-fed to a head tank with sterile gas, and was then supplied to a filling machine, where the drink was filled into bottles having been thermally sterilized and washed beforehand with hot water at 90° C. for 3 seconds, within a controlled space. The drink was then sealed with caps sterilized and washed beforehand. The liquid path from the quick cooling device to the filling machine is a closed path isolated from external air by being positively pressurized with sterile gas.
The pH value, hue and vitamin C of the green tea drink thus obtained were measured immediately after its production, in order to ascertain changes in hue and flavor vis-à-vis green tea drinks manufactured in accordance with a conventional hot pack method. A sensory test was also carried out for assessing palatability.
The results are given in Tables 2, 3 and 4.
Hue was measured in accordance with the L*a*b color specification system. The L*a*b color specification system is a mixed color system in which the L value represents lightness, the a value represents a red-green axis and the b value a yellow-blue axis. A larger L value denotes a lighter color, a greater a value in the positive direction implies stronger redness, and stronger greenness in the negative direction, while a greater b value in the positive direction implies stronger yellowness, and stronger blueness in the negative direction. The ΔE value is obtained by calculating the length of the straight-line distance between two colors in the color space.
To measure vitamin C, the concentration thereof is measured after preparation, with the drink not yet heated. The vitamin C concentration in the drink is measured immediately after the production thereof is over, to determine the residual ratio of the vitamin.
The sensory test was carried out based on three-point discrimination, which affords higher accuracy than two-point discrimination. Two tea drinks to be compared (A of Example 1 and B of Comparative example 1) were combined in various sets of three such as A-A-B, A-B-B and so forth. The combinations were tasted by a panel of 15 panelists, to test discrimination between the two drinks, and for sensory evaluation of the palatability of the drinks.

Example 2

A 100% orange juice acidic drink (pH 3.61) was produced using the above-described equipment and producing method, employing PET bottles having a 1.5 L capacity.
Specifically, the acidic drink having been thermally sterilized at high temperature for a short time, at 94.5 to 96° C. over 30 seconds, followed by rapid cooling to room temperature (31° C. to 32° C. in the present example), was stored in a storage tank kept at a positive pressure with sterile gas and having been sterilized and washed beforehand to a sterilization value equal to or greater than the sterilization value of the content. Thereafter, the acidic drink was bottled into bottles thermally sterilized and washed with hot water at 90° C. for 3 seconds, in accordance with the same method of Example 1. The filling temperature was herein 30° C. As in Example 1, immediately after production of the acidic drink was over, the pH value, hue and vitamin C of the orange juice drink thus obtained were measured immediately after its production, in order to ascertain changes in hue and flavor of the acidic drink vis-à-vis acidic drinks manufactured in accordance with a conventional hot pack method. The results are given in Tables 5 and 6.

Comparative Example 1

In Comparative example 1, a green tea drink (pH 5.9, catechin content 52 mg %) was produced using the equipment and producing method disclosed in Patent document 2, employing PET bottles having a 2 L capacity, as in Example 1. Specifically, a green tea drink having been high-temperature short-time sterilized at 135° C. for 30 seconds, followed by cooling to 65° C., was filled and sealed into bottles sterilized and washed with hot water at 90° C. for 3 seconds, by means of a filling machine and a capper, disposed beforehand in an environment-controlled space isolated from the outside by a box and having been sterilized and washed under the same conditions as the containers. Thereafter, the PET-bottled green tea drink was cooled down to room temperature by means of a simple cooling shower, to yield a green tea drink.
The pH value, hue and vitamin C of the green tea drink thus obtained were measured immediately after its production was over (in this case, after cooling), in order to ascertain changes in hue and flavor, as in Example 1. The two green tea drinks were discriminated and sensorily evaluated in accordance with a three-point discrimination method, as in the examples. The results are given, together with those of Example 1, in Tables 2 to 4.

Comparative Example 2

In Comparative example 2, a 100% orange juice (pH3.61) was produced using the equipment and producing method disclosed in Patent document 2, as in Comparative example 1, employing PET bottles having a 1.5 L capacity, as in Example 2. Specifically, an acidic drink having been high-temperature short-time sterilized at 94.5 to 96° C. for 30 seconds, followed by cooling to 67 to 68° C., was filled and sealed into bottles sterilized and washed with hot water at 90° C. for 3 seconds, by means of a filling machine and a capper, disposed beforehand in an environment-controlled space isolated from the outside by a box and having been sterilized and washed under the same conditions as the containers. The filling temperature was 65° C. Thereafter, the PET-bottled acidic drink was cooled down to room temperature by means of a simple cooling shower, to yield an acidic drink.
The pH value, hue and vitamin C of the acidic drink thus obtained were measured immediately after its production was over (in this case, after cooling), in order to ascertain changes in hue and flavor of the 100% orange juice, as in Example 2. The results are given, together with those of Example 2, in Tables 5 and 6.

Evaluation of Examples and Comparative Examples

Tea Drink

pH Value, Hue:

TABLE 2

pH	L-value	a-value	b-value	ΔE

Prepared	6.38	90.90	−9.90	29.49	Reference
unheated product
Example 1	6.23	89.25	−8.44	32.23	3.52
Comp. example 1	6.19	89.00	−8.14	33.88	5.10

Upon comparison, the hue of the drink in Example 1 is clearly closer to the hue of the prepared unheated product, than is the case in the drink of Comparative example 1, as Table 2 shows. A fresh hue can thus be preserved in Example 1. Likewise, the pH value of the drink in Example 1 can be kept closer to that of the prepared unheated product.
Vitamin C Residual Ratio:

	TABLE 3

	Concentration	Residual
	(ppm)	ratio (%)

Prepared unheated product	283	100.0
Example 1	236	83.4
Comp. example 1	215	76.0

As Table 3 shows, the residual ratio of vitamin C relative to the prepared unheated product was 83.4% in Example 1, but 76% in Comparative example 1. The vitamin C residual rate was clearly higher in the Example.
Palatability Sensory Evaluation:

	TABLE 4

	Panel of 15	Remarks

Discrimination	9 panelists guessed right	Significant difference
test		with 5% significance
		level
Palatability	Among the 9 panelists who	Drink of the Example
test	guessed right, 7	(room-temperature
	preferred the drink of	filling) preferred with
	Example 1, and 2 the	5% significance level
	drink of Comp. example 1

As the results in Table 4 show, 9 panelists among the panel of 15 for sensory evaluation succeeded in telling apart the drinks of Example 1 and Comparative example 1. Of the 9 panelists, 7 preferred the drink of Example 1, which is indicative of the overwhelmingly better palatability of the drink of Example 1 vis-à-vis that of Comparative example 1.
Observation of Changes Over Time
The green tea drink bottled in 2 L PET bottles produced in Example 1 was kept at room temperature for 2 weeks, whereafter the microbial spoilage of the content was observed by visual inspection. The green tea drink exhibited a good condition, with no microbial-spoilage turbidity being observable at all.
100% orange juice (acidic drink)
pH value, hue:

TABLE 5

pH	L-value	a-value	b-value	ΔE

Prepared unheated	3.61	66.66	22.6	42.98	Reference
product
Example 2	3.51	65.35	23.48	42.61	1.62
Comp. example 2	3.51	64.95	24.78	42.2	2.88

Upon comparison, the hue of the drink in Example 2 is clearly closer to the hue of the prepared unheated product, than is the case in the drink of Comparative example 2, as Table 5 shows. A fresh hue can thus be preserved in Example 2. That is, the 100% orange juice of Comparative example 2 exhibited a lower L-value (lightness), a higher a-value (red) and a lower b-value (yellow) than the drink of Example 2.
Vitamin C Residual Ratio:

	TABLE 6

	Concentration	Residual
	(ppm)	ratio (%)

Prepared unheated product	283	100.0
Example 2	270	95.4
Comp. example 2	245	86.6

As Table 6 shows, the residual ratio of vitamin C relative to the prepared unheated product was 95.4% in Example 2, but 86.6% in Comparative example 2. The vitamin C residual rate was clearly higher in Example 2.
Overall Evaluation
The drinks of Examples 1 and 2 were superior to the drinks of Comparative examples 1 and 2 as regards hue measurement, pH value measurement and residual ratio of vitamin C. Examples 1 and 2 allow obtaining thus drinks of excellent quality, in which the fresh hue of the drink can be preserved, with a high residual ratio of vitamin C.
Also, the results of the panel sensory test performed on the drinks of Example 1 and Comparative example 1 attest the overwhelmingly higher palatability of the drink of the Example. This bears out the effectiveness of the method for producing a packaged drink of the present invention when used for packaging tea drinks and acidic drinks.

Example 3

A green tea drink (pH 5.9, catechin content 52 mg %) was produced using the above-described equipment and producing method, employing PET bottles having a 2 L capacity.
Specifically, the controlled space in which containers are washed, filled and sealed was sterilized beforehand at 40° C. for 10 minutes using a peracetic acid chemical agent (trade name: Toyo Active) at a concentration of 2000 ppm, followed by washing with hot water at 90° C. An antiseptic effect of 6 D or higher against spore-forming bacteria such as B. subtilis, B. coagulans was observed. Then, a green tea drink having been thermally sterilized at high temperature for a short time, at 135° C. over 30 seconds, followed by rapid cooling to room temperature, was stored in a storage tank kept at a positive pressure with sterile gas and having been sterilized and washed beforehand to a sterilization value equal to or greater than the sterilization value of the content. Thereafter, the drink was pressure-fed to a head tank with sterile gas, and was then supplied to a filling machine, where the drink was filled into bottles having been thermally sterilized and washed beforehand with hot water at 90° C. for 3 seconds, within a controlled space. The drink was then sealed with caps sterilized and washed beforehand. The liquid path from the quick cooling device to the filling machine is a closed path isolated from external air by being positively pressurized with sterile gas.
The pH value, hue and vitamin C of the green tea drink thus obtained were measured immediately after its production, in order to ascertain changes in hue and flavor vis-à-vis green tea drinks manufactured in accordance with a conventional hot pack method. A sensory test was also carried out for assessing palatability.
The results are given in Tables 7, 8 and 9.
As before, hue was measured in accordance with the L*a*b (L-star, a-star, b-star) color specification system.
To measure vitamin C, the concentration thereof is measured after preparation, in an unheated state. The vitamin C concentration in the drink is measured immediately after the production thereof is over, to determine the residual ratio of the vitamin.
The sensory test was carried out based on three-point discrimination, which affords higher accuracy than two-point discrimination. Two tea drinks to be compared (A of Example 3 and B of Comparative example 3) were combined in various sets of three such as A-A-B, A-B-B and so forth. The combinations were tasted by a panel of 20 panelists, to test discrimination between the two drinks, and for sensory evaluation of the palatability of the drinks.

Example 4

A 100% orange juice acidic drink (pH 3.61) was produced using the above-described equipment and producing method, employing PET bottles having a 1.5 L capacity.
Specifically, the controlled space in which containers are washed, filled and sealed was sterilized beforehand at 40° C. for 10 minutes using a peracetic acid chemical agent (trade name: Toyo Active) at a concentration of 2000 ppm, followed by washing with hot water at 90° C. The acidic drink having been thermally sterilized at high temperature for a short time, at 94.5 to 96° C. over 30 seconds, followed by rapid cooling to room temperature (31° C. to 32° C. in the present example), was stored in a storage tank kept at a positive pressure with sterile gas and having been sterilized and washed beforehand to a sterilization value equal to or greater than the sterilization value of the content. Thereafter, the acidic drink was bottled into bottles thermally sterilized and washed with hot water at 90° C. for 3 seconds, in accordance with the same method of Example 3. The filling temperature was herein 30° C. As in Example 3, immediately after production of the acidic drink was over, the pH value, hue and vitamin C of the orange juice drink thus obtained were measured immediately after its production, in order to ascertain changes in hue and flavor of the acidic drink vis-à-vis acidic drinks manufactured in accordance with a conventional hot pack method. The results are given in Tables 10 and 11.

Comparative Example 3

In Comparative example 3, a green tea drink (pH 5.9, catechin content 52 mg %) was produced using the equipment and producing method disclosed in Patent document 2, employing PET bottles having a 2 L capacity, as in Example 3. Specifically, a green tea drink having been high-temperature short-time sterilized at 135° C. for 30 seconds, followed by cooling to 65° C., was filled and sealed into bottles sterilized and washed with hot water at 90° C. for 3 seconds, by means of a filling machine and a capper, disposed beforehand in an environment-controlled space isolated from the outside by a box and having been sterilized and washed under the same conditions as the containers. Thereafter, the PET-bottled green tea drink was cooled down to room temperature by means of a simple cooling shower, to yield a green tea drink.
The pH value, hue and vitamin C of the green tea drink thus obtained were measured immediately after its production was over (in this case, after cooling), in order to ascertain changes in hue and flavor, as in Example 3. The two green tea drinks were discriminated and sensorily evaluated in accordance with a three-point discrimination method, as in the examples. The results are given, together with those of Example 3, in Tables 7 to 9.

Comparative Example 4

In Comparative example 4, a 100% orange juice (pH 3.61) was produced using the equipment and producing method disclosed in Patent document 2, as in Comparative example 1, employing PET bottles having a 1.5 L capacity, as in Example 4. Specifically, an acidic drink having been high-temperature short-time sterilized at 94.5 to 96° C. for 30 seconds, followed by cooling to 67 to 68° C., was filled and sealed into bottles sterilized and washed with hot water at 90° C. for 3 seconds, by means of a filling machine and a capper, disposed beforehand in an environment-controlled space isolated from the outside by a box and having been sterilized and washed under the same conditions as the containers. The filling temperature was 65° C. Thereafter, the PET-bottled acidic drink was cooled down to room temperature by means of a simple cooling shower, to yield an acidic drink.
The pH value, hue and vitamin C of the acidic drink thus obtained were measured immediately after its production was over (in this case, after cooling), in order to ascertain changes in hue and flavor of the 100% orange juice, as in Example 4. The results are given, together with those of Example 4, in Tables 10 and 11.

Evaluation of Examples and Comparative Examples

Tea Drink

pH Value, Hue:

TABLE 7

pH	L-value	a-value	b-value	ΔE

Prepared	6.44	91.50	−10.30	30.05	Reference
unheated product
Example 3	6.30	89.95	−8.50	33.35	3.69
Comp. example 3	6.25	88.91	−8.20	34.11	5.25

Upon comparison, as Table 7 shows, the hue of the drink in Example 3 is clearly closer to the hue of the prepared unheated product, than is the case in the drink of Comparative example 3. A fresh hue can thus be preserved in Example 3. Likewise, the pH value of the drink in Example 3 can be kept closer to that of the prepared unheated product.
Vitamin C Residual Ratio:

	TABLE 8

	Concentration	Residual
	(ppm)	ratio (%)

Prepared unheated product	305	100.0
Example 3	260	85.2
Comp. example 3	236	77.4

As Table 8 shows, the residual ratio of vitamin C relative to the prepared unheated product was 85.2% in Example 3, but 77.4% in Comparative example 3. The vitamin C residual rate was clearly higher in the Example.
Palatability Sensory Evaluation:

	TABLE 9

	Panel of 20	Remarks

Discrimination

	12 panelists guessed right	Significant difference
test		with 5% significance
		level
Palatability	Among the 12 panelists	Drink of the Example
test	who guessed right, 8	(room- temperature
	preferred the drink of	filling) preferred with
	Example 3, and 4 the	5% significance level
	drink of Comp. example 3

As the results in Table 9 show, 12 panelists among the panel of 20 for sensory evaluation succeeded in telling apart the drinks of the Example and the Comparative example. Of the 12 panelists, 8 preferred the drink of Example 3, which is indicative of the overwhelmingly better palatability of the drink of Example 3 vis-à-vis that of Comparative example 3.
Observation of Changes Over Time
The green tea drink bottled in 2 L PET bottles produced in Example 3 was kept at room temperature for 2 weeks, whereafter the microbial spoilage of the content was observed by visual inspection. The green tea drink exhibited a good condition, with no microbial-spoilage turbidity being observable at all.
100% orange juice (acidic drink)
pH value, hue:

TABLE 10

pH	L-value	a-value	b-value	ΔE

Prepared unheated	3.55	67.61	22.00	43.32	Reference
product
Example 4	3.46	65.90	24.10	43.01	2.73
Comp. example 4	3.46	65.03	25.04	42.60	4.05

Upon comparison, as Table 10 shows, the hue of the drink in Example 4 is clearly closer to the hue of the prepared unheated product, than is the case in the drink of Comparative example 4. A fresh hue can thus be preserved in Example 4. That is, the 100% orange juice of Comparative example 4 exhibited a lower L-value (lightness), a higher a-value (red) and a lower b-value (yellow) than the drink of Example 4.
Vitamin C Residual Ratio:

	TABLE 11

	Concentration	Residual
	(ppm)	ratio (%)

Prepared unheated product	320	100.0
Example 4	295	92.2
Comp. example 4	276	86.3

As Table 11 shows, the residual ratio of vitamin C relative to the prepared unheated product was 92.2% in Example 4, but 86.3% in Comparative example 4. The vitamin C residual rate was clearly higher in Example 4.
Overall Evaluation
The drinks of Examples 3 and 4 were superior to the drinks of Comparative examples 3 and 4 as regards hue measurement, pH value measurement and residual ratio of vitamin C. Examples 3 and 4 allow obtaining thus drinks of excellent quality, in which the fresh hue of the drink can be preserved, with a high residual ratio of vitamin C.
Also, the results of the panel sensory test performed on the drinks of Example 3 and Comparative example 3 attest the overwhelmingly higher palatability of the drink of the Example. This bears out the effectiveness of the method for producing a packaged drink of the present invention when used for packaging tea drinks and acidic drinks.

INDUSTRIAL APPLICABILITY

The method for producing a packaged drink of the present invention can be appropriately used for producing packaged drinks of non-nutritionally enriched drinks in which growth of spore-forming bacteria is difficult after heating, for instance, drinks such as green tea, Oolong tea or the like comprising 30 mg % or more of catechins at a pH of 4.6 or higher, acidic drinks of pH lower than 4.6, mineral water or the like. The containers are not limited to synthetic resin bottles such as PET bottles or the like. The invention can also be used for other container types such as metal bottles, metal cans, glass bottles or the like.

Claims

1. A method for producing a packaged drink, comprising the steps of: thermally sterilizing and washing beforehand, using hot water at 65° C. to 100° C. or a chemical agent, a surrounding environment where a container and a cap are sterilized, washed, filled and sealed; thermally sterilizing and washing beforehand a liquid-feeding pathway, up to a cooling device, a storage tank and a filling machine, under conditions equal to or exceeding the thermal sterilization conditions of a drink to be filled; and thermally sterilizing and washing at least an inner surface of the container and cap with hot water at 65° C. to 100° C., wherein the drink to be filled is thermally sterilized up to a predetermined sterilization value and is thereafter quickly cooled to room temperature, the cooled drink being stored in the storage tank, and wherein a content liquid is fed to the filling machine to make the liquid-feeding pathway into a closed liquid-feeding pathway into which outer air does not intrude, and the surrounding environment is made an environment-controlled space isolated from the outside, such that the drink is filled at room temperature into the sterilized container and then sealed in the environment-controlled space.

2. The method for producing a packaged drink according to claim 1, wherein the drink is a drink comprising 30 mg % or more of catechins at a pH of 4.6 or higher, and the drink is thermally sterilized to a sterilization value equal to or higher than 135° C. and 7.58 seconds.

3. The method for producing a packaged drink according to claim 1, wherein the drink is an acidic drink having a pH below 4.6, and the acidic drink is thermally sterilized to a sterilization value equal to or higher than 85° C. and 30 minutes.

4. The method for producing a packaged drink according to claim 1, wherein the environment-controlled space is a space housed in a box.

5. The method for producing a packaged drink according to claim 1, wherein the storage tank is kept at positive pressure with sterile gas, and the liquid is fed from the storage tank to the filling machine through pressure-feeding by sterile gas.

6. The method for producing a packaged drink according to claim 1, wherein washing which is performed after thermal sterilization and washing of the surrounding environment using a chemical agent has also a sterilizing function by using hot water at 65° C. to 100° C.

7. The method for producing a packaged drink according to claim 1, wherein any of a peracetic acid chemical agent, hydrogen peroxide, an ozone-based chemical agent, and a chlorine-based disinfectant containing hypochlorous acid is used as the chemical agent for sterilizing and washing beforehand the surrounding environment where a container and a cap are sterilized, washed, filled and sealed.