IE902337A1 - Process for sterile addition of additives - Google Patents

Abstract

This invention concerns a method and apparatus for the addition of sterile and aseptic additives to fluids in sterile and aseptic fluid processing systems.

Description

PROCESS FOR STERILE ADDITION OF ADDITIVES BACKGROUND OF THE INVENTION FIELD OF THE INVENTION This invention concerns a method and apparatus for the addition of sterile or aseptic ingredients to fluids in sterile or aseptic fluid processing systems. Sterile and aseptic processing are used in various industries where it is necessary to sterilize or purify an initial fluid product and package the product without contamination.

In general, aseptic processing has meant the initial high temperature treatment, for a short period of time, of a single fluid or a mixture of a principal fluid, along with various additives, followed by the packaging of the sterile fluid so as to avoid recontamination. One problem associated with the mixing of a fluid and additives prior to a high temperature sterilization or purification treatment is the sensitivity of various additives to the high temperature. For example, colorants and flavorants used in beverage processing are adversely affected by thermal processing. The present invention provides a method of adding sterile or aseptic ingredients to a processing operation, after a high temperature or other sterilization or purification step, without contamination of the mixture. The invention further relates to a method and apparatus for adding additives to products that are not initially sterile but have been purified in some way (e.g. pasteurized milk or orange juice), where the introduction of contaminants into the system is not desired.

DESCRIPTION OF THE PRIOR ART A basic requirement for the equipment used in aseptic processes is the capability to be cleaned in place and maintained in aseptic condition while the equipment is in use. Various methods of sterile and/or aseptic fluid processing are reviewed on pages 29 through 32 of Encyclopedia of Food Engineering, Second Edition, Carl W. Hall, A.W. Farrall, A.L. Rippen, AVI Publishing Company, Inc., Westport, Ct. (1986).

While early processing developments concerned the aseptic packaging of a single pure product or a previously mixed product, without the later addition of additives, more recent processing operations, for fruit drinks and juices for example, have required the addition of various sterile additives to enhance a product's flavor, as preservatives, as colorants or to give a product other desirable characteristics. Some of these additives would be destroyed or discolored if exposed to high temperatures or other rigorous sterilization procedures. Various developments have occurred in the pretreatment of additives with the aim of avoiding contamination or denaturization.

U.S. Patent No. 4,534,991 discloses a process for making an aseptic juice wherein the aseptic flavoring for the juice is made by adding a high proof alcohol to the flavor concentrate ingredients and adding that mixture to the previously pasteurized juice. The flavoring is selfsterilizing due to the high alcohol content.

U.S. Patent No. 5,547,384 discloses a process and juice product resulting from dissolving the dipeptide of L-phenylalanine and L-aspartic acid in a solvent along with an excess of malic or citric acid. The solution is added to a pasteurized drink.

Neither of the two above patents address the possibility of contamination of the product as additives are being added.

Various prior art patents have addressed the forming of a sterile connection for use in medical or scientific procedures. Two areas where sterile splicing would be useful are cited in several of the patents. Those two areas are in replacing dialysate liquid bags in continuous ambulatory peritoneal dialysis (CAPD) procedures and in processing blood in bags to separate components, and add treating agents.

U.S. Patent No. 4,369,799 discloses a process and apparatus for aligning, cutting and making a sterile connection between two thermoplastic resin tubes.

U.S. Patent No. 4,610,670 discloses an apparatus and a method for first flattening and sealing thermoplastic tube ends then joining aligned opposing molten tube ends together to form a weld so as to join the two ends of the tube.

U.S. Patent No. 4,629,642 includes a method and apparatus for forming a connection between a pair of sterile tubes.

U.S. Patent No. 4,753,697 discloses an apparatus for holding tubes to be joined in a folded position, then cutting the folded tubes so that cut tubes can be welded to one another without substantial realignment.

SUMMARY OF THE INVENTION According to the invention there is provided in a sterile or aseptic system for processing fluids, wherein fluids are first sterilized or purified and measured amounts of additives are introduced into the sterilized or purified fluid within a processing line, after a sterilization or purification step and before a packaging step, the improvement comprising the introduction of additive fluid from additive containers having plastic tubing extending therefrom said tubing serves as a conduit for additive fluid leaving the additive container and the connection of said tubing, by sterile connection means, to plastic tubing attached to and extending from a port in the processing line. -3aIn another aspect the invention provides in a sterile or aseptic system for processing fluids, wherein fluids are first sterilized or purified in bulk and measured amounts of additives are introduced into the sterilized or purified fluid within a processing line, after a sterilization or purification step and before a packaging step, the improvement comprising the introduction of additive fluid from additive containers having plastic tubing extending therefrom said tubing serves as a conduit for additive fluid leaving the additive container and the connection of said tubing, by sterile connection means, to plastic tubing attached to and extending from a port in the processing line.

In a further aspect the invention provides in a sterile or aseptic system for processing fluid food products, wherein liquids are first sterilized or purified and measured amounts of additives are introduced into the sterilized or purified fluid within a processing line, after a sterilization or purification step, and before a packaging step, so that no additional sterilization or purification of the fluid food product is required, the improvement comprising the introduction of additive fluid from additive containers having plastic tubing extending therefrom said tubing serves as as a conduit for additive fluid leaving the additive container and the connection of said tubing, by sterile connection means, to plastic tubing attached to and extending from a port in the processing line.

In another aspect the invention provides a method for preparing a sterile or an aseptic fluid mixture containing additives which are added to a processing line from an additive container having a first sterile plastic tube extending therefrom, after a sterilization or purification process, comprising the steps of: -3b(a) connecting to said first sterile plastic tube, by sterile connection means, a second sterile plastic tube that is connected to and extends out from a port in the fluid processing line, so that the first and second plastic tubes form an open conduit for fluid; (b) adding a sterile or aseptic additive, located in the additive container, to the fluid in the processing line by causing the additive to flow through the first and second thermoplastic tubes; (c) avoiding sterilizing the system after the aseptic additive has been added to the liquid in the processing line The present invention relates to a novel system of introducing sterile or aseptic additives, for use at various points in a sterile or aseptic fluid processing system, that may be used, for example, in food processing, so as to avoid contamination of the fluid processing system or of the additives. The method of the present invention permits the introduction of sterile or aseptic ingredients to a fluid after the fluid has been sterilized or purified, by employing the combination of a system of sterile plastic connective tubes connected to a fluid processing line and a sterile tube connection process to connect a container of additive to the tube leading to the fluid processing line. The term fluid processing line is meant to include all tanks, equipment and apparatus through which a principal fluid flows as it goes through the various processing steps. The system permits a container of additive that is connected to a process line to be removed and replaced with a different additive container without contaminating the fluid process system or the additives.

Accordingly, the object of the present invention is to provide a process for aseptically introducing additives into a fluid processing system.

Another object of the present invention is to provide a process for aseptically introducing additives into a food processing system.

A further object of the present invention is to avoid the deficiencies of prior art systems for adding additives, such as contamination of the access tubes, contamination of the product, denaturization of the additives and difficulty of cleaning the system.

Another object of the present invention is to provide a system for adding first one sterile or aseptic additive to a fluid processing system and then switching to another sterile or aseptic additive, while the fluid processing system is operating, without contaminating the process system or the additives.

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for the introduction of sterile or aseptic additives into a previously sterilized or purified (e.g. pasteurized) fluid, within a fluid processing system, without contaminating the fluid system or the additives.

By sterilization is meant ...an absolute term meaning the destruction of all life. Disinfection, Sterilization and Preservation, Third Edition, Seymour S. Bock, Editor, Lea and Febiger (1983). In the food industry, The term commercial sterilization has ... been used to describe the situation in which all pathogenic microorganisms and their spores in the food are inactivated... Article by Daryl B. Lund, Thermal Processing. Encyclopedia of Food Engineering, Second Edition, (1986), p. 788. Two basic methods are employed to produce commercially sterile packaged food products. In one method, the food is placed in a container, sealed and thermally processed. This is referred to as conventional canning. The second method, referred to as aseptic canning requires that the thermally processed product be placed in sterile containers then sealed. Id at p. 791.

By Pasteurization is meant ...a heat treatment that kills part of but not all of the vegative microorganisms present in the food and consequently is used for foods that are further handled and stored under conditions that minimize growth. Daryl B. Lund, Thermal Processing. Encyclopedia of Food Engineering, p. 787, supra.

A flow diagram for the conventional processing of a sterile or aseptic fluid is shown below. A fluid or mixture of dry and fluid ingredients is added to a mix tank. From the mix tank, the fluid flows to another location where it is sterilized or purified (hereinafter Sterilization Step). After the Sterilization Step, the fluid flows to a filler and into packages using conventional aseptic packaging technology. If heat is used for sterilization or purification, the fluid may be cooled before it reaches the filler equipment, using existing cooling technology (e.g. heat exchanger).

MIX STE? (optonal) FILLER TANK □ODIIII The present invention modifies the conventional process above by introducing a method and apparatus for introducing additives into the processing system at one or more points located between the sterilization step and filler step.

A flow diagram for the processing of a generic mix utilizing the present invention's method of introducing additives is shown below. A fluid or mixture of dry and fluid ingredients is added to a Mix Tank. The fluid goes through a Sterilization Step. After the Sterilization Step” and, possibly, a cooling step, if heat is used in the Sterilization Step, additional ingredients are added to form a mixture of additive and original fluid (hereinafter Flavored Mix). This is accomplished by means of a sterile ingredient addition system (hereinafter SIAS). The SIAS method taught herein is a system of valves, plastic tubes and sterile connection means ( e.g. sterile heat welding as in U.S. patent No. 4,610,670 or sterile spike connections as in Baxter-Travenol UVFlash™ Germicidal Exchange Device). Sterile connection means include means for connecting a second tube to a first tube having a free end and which is closed to prevent contamination and having the other end attached to some apparatus (e.g. a container, valve or pipeline) or a first tube that has no free ends (e.g. each end is attached to some apparatus). The system for adding additives is connected into the fluid processing line, as will be further described herein in relation to the detailed discussion of the drawings. The term heat welding as used herein refers to a method of connecting two sealed thermoplastic tubes (the tubes are initially sealed to avoid contamination) having substantially the same diameters by cutting, melting and joining the ends of the tubes together so that a sterile connection between the tubes is formed. One embodiment of the heat welding means is described in U.S. Patent No. 4,610,670. That patent describes a device in which a pair of tubes to be connected is flattened and a hot cutting means is passed through the tubes. This temporarily seals the ends of the tubes and provides molten tube ends. The tubes are aligned, then the tubes to be connected are urged together to form a welded joint between the tubes. The joint is cooled then subjected to light stress to open the temporary seals thereby providing means for fluid communication between the joined tubes. Other alternative embodiments are described in U.S. Patents Nos. 4,369,799, 4,629,642 and 4,743,697, which are incorporated herein by reference.

The Flavored Mix then flows through a mixing system (if mixing is required) and is then transferred to a filling apparatus and into packages using conventional aseptic packaging technology.

Various changes in the configuration of such a system can be anticipated. Two alternative configurations are shown below.

ESI SIAS SIAS SIAS SIAS SIAS MIXER (optional) SIAS MIXER (optional) MIXER (optional) j I FILLER FILLER FILLER □□□Bias □□□am □ □□am A plastic tube leading from an ingredient bottle is aseptically connected to a plastic tube, which is connected to the process line (or equipment). In the food industry, the process line, itself, is generally made of some rigid material such as stainless steel. The connected tubes leading from the ingredient container(s) to the process line (or equipment) allow transfer of additive material to the fluid in the process line (or equipment), through a port or ports in the process line (or equipment).

Several suggested configurations for the sterile ingredient addition system are described by the attached drawings and are explained below: BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 (a-e) is a diagram for one embodiment of the current invention's additive system connected to a conventional process line.

Fig. 2 shows the current invention having a persitaltic pump.

Fig. 3 shows the current invention having a metering pump.

Fig. 4 shows a system having additive connections in two places and having a metering pump and filter with sterile connections used to connect the filter to the processing system.

Fig. 5 shows the SIAS used with two process systems connected by means of a sterile connection.

Fig. 6(a) and 6(b) shows the switching of additive containers while a process is operating.

DETAILED DESCRIPTION OF THE DRAWINGS Fig. 1(a) shows a process pipeline 5 connected by conduit tube 13 to three-way valve 1. Valves 2 and 3 are two-way valves. The ends 6 and 7 are free ends with quick disconnects (e.g. Tri-Clamp® fittings). Lines 8 and 9 are connected to a cleaning and/or sterilizing system (e.g. steam) The process pipeline and equipment are cleaned and sterilized with valve 1 positioned to allow the flow of steam or other sterilizing fluid from process line 5 through line 8. Valve 3 is closed. Valve 2 is open. This configuration allows part of the sterilizing fluid to flow from pipeline 5 through tube 13, through valves 1 and 2 and out line 8 or from line 8, through valves 2 and I and out pipeline 5.

Fig 1(b) shows an apparatus 20 to be connected to free tube ends 6 and 7 shown in figure 1(a). Valve 4 is a three-way valve with one port connected to thermoplastic tubing 12 which is sealed at its outer end 29. The other two ports of valve 4 have conduit tubing attached with free ends 10 and 11. The free ends 10 and II have quick disconnects (e.g. Tri-Clamp® fittings) which match the quick disconnects on free ends 6 and 7 in Fig. 1(a). Valve 4 is positioned to block flow to the sealed thermoplastic tubing 12 when apparatus 20 is sterilized. The valve and tube apparatus 20 may be sterilized by autoclaving, radiation or other methods ι ο which do not require physical access to the inside of valve 4 or tubing 12. If it is desired to use a method that requires such physical access (e.g. use of ethylene oxide), valve 4 may be opened to allow flow to tubing 12 but must be repositioned to block flow to tubing 12 after the sterilization process is complete in order to maintain sterility of tubing 12.

Fig. 1(c) shows apparatus 20 connected to the configuration in Fig. 1(a). Connections 14 and 15 between the ends of tubes 6 and 10 and and end of tubes 7 and 11 are made using quick disconnect fittings. When apparatus 20 is connected, valve 1 is positioned to allow flow from process line 5 through line 8, as explained for Fig. 1(a). Valve 2 is open. Valve 3 is closed. Valve 4 is positioned to prevent flow to tubing 12. The valves remain in these positions, as described by Fig. 1(a) and Fig. 1(b), to this point in the sterilization process, without being repositioned at any time, because repositioning of the valves may jeopardize the sterility of the valves and lines. After apparatus 20 is connected, valve 3 is opened and valve 1 is positioned to block flow to line 5. Valve 2 remains open and valve 4 remains positioned to block flow to tubing 12. This arrangement allows the appropriate amount of sterilization media to flow in line 8, through valves 2, 1, 4 and 3 and out line 9 or vice versa. Valve 1, valve 4 and line 16 are sterilized by the appropriate media flowing in line 8, through the valves and out line 9 or vice versa.

Fig. 1(d) shows a container 18 to be used in the process configuration shown in Fig. l(a-c). Container 18 has a conduit tubing 17 made of thermoplastic tubing which is an integral part of the container or part of a detachable container cap (not shown). Conduit tubing 17 is compatible with tubing 12 and is sealed at the free end. Container 18 can be filled with an aseptic additive which can be attached to the process line 12 by sterile connection means (not shown).

Fig. 1(e) shows the process configuration with the additive container 18 connected thereon. Conduit tubing 17 and tubing 12 are connected by sterile connection means. To make a sterile connection 21 by heat welding, tubing 12 and 17 are severed then aligned. The cut ends are melted (e.g. by having a heated wafer pass through them) The two melted ends to be connected are urged together, thus creating a weld that protects the joint against contamination. After the connection process is completed, valves 2 and 3 are closed and valves 1 and 4 are positioned to allow flow from the additive container 18 through valves 4 and 1 to process line 5. Container 18 can be collapsible or rigid. If a rigid container is used, the container must have a vent (not shown) or be attached to a venting or purging system (not shown) to prevent contamination by incoming air as the container is emptied. If a vent is used, the vent should be equipped with a filter that sterilizes the air as it passes through. With a vent or purge system, the container would fill with the appropriate purge (e.g. nitrogen or sterile air) as the container is emptied. The container could be attached to the vent and purge system using sterile heat welding technology. The container would have two conduit tubes extending therefrom; one of said tubes to be attached to the process (tubing 12 in Fig. 1 (d)) and one to be attached to a conduit tubing from the vent and purge system (not shown) or is left open for the admission of air through a sterilizing filter (not shown).

Fig 2 shows a processing line numbered as in Figures l(a-e) with an attached peristaltic pump 22.

Fig. 3 shows metering pump 24 in the system.

Fig. 4 shows a system with metering pump 24 and filter 25. Sterile tube connections can be made in the thermoplastic tubes at positions 26 and 27 for attachment of filter 25.

Fig. 5 shows a process line numbered as in Figures l(a-e) with a second process system 28 connected 2 to it. The second process may be a specialty process for processing the ingredient that is to be added to process line 5.

Fig. 6 (a) and 6(b) show a process line numbered as in l(a-e) above with two different additive containers 18 and 19 for attachment thereto. To change additive containers, sterile welding technology (e.g. as described in U.S. Patent No. 4,610,670) can be used. The valve positions do not change and the process line does not need to be shut down.

Where slicing and heat welding of thermoplastic tubing is required, it is assumed that some tubing will be lost due to the cutting and heat welding processes. Where conduit tubing becomes too short for convenient manipulation, additional sections of thermoplastic tubing can be added to existing tubing to increase the length of such existing tubing using sterile tube welding technology.

Although preferred embodiments of the invention have been illustrated and described hereinabove, it is to be understood that there is no intent to limit the invention to the precise constructions described and it is further understood that the right is reserved to all changes and modifications which fall within the scope of the claims.

Claims (25)

1. In a sterile or aseptic system for processing fluids, wherein fluids are first sterilized or purified and measured amounts of additives are introduced into the sterilized or purified fluid within a processing line, after a sterilization or purification step and before a packaging step, the improvement comprising the introduction of additive fluid from additive containers having plastic tubing extending therefrom said tubing serves as a conduit for additive fluid leaving the additive container and the connection of said tubing, by sterile connection means, to plastic tubing attached to and extending from a port in the processing line.

2. An apparatus according to Claim 1 wherein the sterile connection means is heat welding.

3. The apparatus according to Claim 1 having a fluid pump located in the plastic tubing line between the additive container and the processing line.

4. Γη a sterile or aseptic system for processing fluids, wherein fluids are first sterilized or purified in bulk and measured amounts of additives are introduced into the sterilized or purified fluid within a processing line, after a sterilization or purification step and before a packaging step, the improvement comprising the introduction of additive fluid from additive containers having plastic tubing extending therefrom said tubing serves as a conduit for additive fluid leaving the additive container and the connection of said tubing, by sterile connection means, to plastic tubing attached to and extending from a port in the processing line.

5. An apparatus according to Claim 4 wherein the sterile connection means is heat welding. 1 4

6. An apparatus according to Claim 5 having a fluid pump located in the plastic tubing line between the additive container and the processing line.

7. In a sterile or aseptic system for processing fluid food products, wherein liquids are first sterilized or purified and measured amounts of additives are introduced into the sterilized or purified fluid within a processing line, after a sterilization or purification step, and before a packaging step, so that no additional sterilization or purification of the fluid food product is required, the improvement comprising the introduction of additive fluid from additive containers having plastic tubing extending therefrom said tubing serves as as a conduit for additive fluid leaving the additive container and the connection of said tubing, by sterile connection means, to plastic tubing attached to and extending from a port in the processing line.

8. The apparatus of Claim 7 wherein the sterile connection means is heat welding.

9. The apparatus of Claim 7 having a fluid pump located in the plastic tubing line between the additive container and the processing line.

10. A method for preparing a sterile or an aseptic fluid mixture containing additives which are added to a processing line from an additive container having a first sterile plastic tube extending therefrom, after a sterilization or purification process, comprising the steps of: (a) connecting to said first sterile plastic tube, by sterile connection means, a second sterile plastic tube that is connected to and extends out from a port in the fluid processing line, so that the first and second plastic tubes form an open conduit for fluid; (b) adding a sterile or aseptic additive, located in the additive container, to the fluid in the processing line by causing the additive to flow through the first and second thermoplastic tubes; (c) avoiding sterilizing the system after the aseptic additive has been added to the liquid in the processing line.

11. A process according to Claim 10 wherein the method for connecting the plastic tube leading from the additive container to the plastic tube leading to the fluid processing line is heat welding.

12. A process according to Claim 10 wherein the additive is pumped through the first and second thermoplastic tubes to the fluid in the processing line.

13. A method of preparing a potable fruit juice beverage comprising the steps of: (a) subjecting fruit juice to a pasteurization or sterilization step using pasteurization or sterilization apparatus resulting in a pasteurized or sterilized juice; (b) adding aseptic or sterile additives to said pasteurized or sterilized juice forming a juice mixture, by means of sterilized plastic tubular conduits leading from containers containing the additives by connecting, by sterile connection means, said tubular conduits to plastic tubes leading to the juice pasteurization apparatus; (c) avoiding pasteurization or sterilization of the juice mixture after the aseptic or sterile additives have been added to the previously pasteurized or sterilized juice.

14. The process of Claim 13 wherein the method of connecting the tubular conduits leading from the additive containers to the tubes leading to the juice pasteurization apparatus is heat welding.

15. A process for preparing potable milk containing additives comprising the steps of: (a) Subjecting the milk within a milk processing line to a pasteurization step, using pasteurization or sterilization apparatus, resulting in pasteurized or sterilized milk; (b) adding aseptic or sterile additives to said sterilized or pasteurized milk, forming a milk mixture, by means of sterilized plastic tubular conduits leading from containers containing the additives by connecting, by sterile connection means, said conduits to sterile plastic tubes leading to ports in the milk processing line; (c) avoiding pasteurization or sterilization of the milk mixture after the aseptic or sterile additives have been added to the previously pasteurized or sterilized milk

16. The process of Claim 15 where the means for connecting the tubular conduit extending from additive container to the tube leading to the milk processing line consists of heat welding the plastic tubes to one another to form a sterile connection.

17. In a process for preparing cultured dairy products wherein the process involves purifying or sterilizing a dairy product within vessel or container and adding aseptic starter cultures located in additive containers having plastic tubular conduits extending therefrom, to the purified or sterile product, so that further purifying or sterilization is not necessary, the improvement comprising attaching said plastic tubular conduits leading from the additive containers containing the starter cultures to plastic tubes leading to the daily product vessel or container, by connecting, by sterile connection means, said plastic tubes together.

18. The process of Claim 17 wherein the method of connecting the plastic tubular conduits leading from the additive containers to plastic tubes leading to the dairy product vessel or container is by heat welding said tubes to one another.

19. In a fluid processing apparatus wherein a fluid flows through a process line wherein sterile or aseptic additives are added to the fluid located in the process line through ports in the process line, the improvement comprising attaching additive containers having one or a plurality of plastic tubes extending therefrom to one or a plurality of sterilized plastic conduit tubes leading to ports in said processing line, by connecting, by sterile connection means, said plastic tubes together.

20. An apparatus according to Claim 19 wherein the means for connecting the plastic conduit tubes leading from the additive containers to plastic tubes leading to the process line is heat welding.

21. An apparatus according to Claim 19 wherein there is located between the fluid line and the plastic conduit tubes a system of valves and tubes for presterilization of the process line prior to addition of additives.

22. An apparatus according to Claim 21 wherein the said system of valves and tubes includes (a) a first three-way valve connected by tubular connection means to said processing line; (b) a first two-way valve connected by means of tubular connection means to said first three-way valve at one end and attached by tubular connection means to means for accessing sterilizing fluid/gas at the other end; (c) a second three-way valve connected by tubular connection means to the first three-way valve at one of said first three-way valve's ends; (d) a second two-way valve connected at one end by tubular connection means to a second end of the second three-way valve and attached by tubular connection means to means for transmitting sterilizing fluid at the other end; (e) a plastic tube attached to a third end of the second three-way valve, said plastic tube being closed at the free end to prevent contamination once sterilized and used for attachment to a sterile tube connected to an additive container. -1823. A sterile or aseptic system for processing fluids substantially as hereinbefore described with reference to the drawings.

23. 24. A method for preparing a sterile or an aseptic fluid mixture substantially as hereinbefore described with reference to the accompanying drawings.

24.

25. A fluid mixture whenever prepared by a method as claimed in any of claims 10 to 14, 15 to 17 or 24.