Continuous fluid sampler and method

A method of using an aseptic sampling arrangement. The sampling arrangement includes a septum cartridge and a securing element for use with a fluid enclosure. A locking arrangement is provided to allow selective access to the septum cartridge and the securing element. The sampling arrangement further includes a needle, a tube, and a collection bag. The sampling arrangement can be used to monitor the quality of a fluid product. The method of monitoring includes obtaining a fluid product sample from the fluid enclosure within the collection bag. The collection bag is then incubated for a period of time during which oxygen permeates the bag to simulate post-pasteurizing conditions and/or pre-pasteurizing conditions of the fluid product. The method further includes monitoring the level of contamination detected within the fluid product sample.

FIELD OF THE INVENTION

This disclosure concerns a sampling arrangement. More specifically, this disclosure describes the assembly and method of use of a sampling arrangement for aseptic, continuous sampling of a fluid material.

BACKGROUND OF THE INVENTION

There are numerous applications wherein it is desirable to obtain discrete or continuous samples from fluid transportation systems or fluid processing enclosures. Enclosures and fluid transportation systems, as used herein, refer to any closed containment structure without respect to its size. Thus it includes such small enclosures such as cans that may be used in shipping starter bacteria from a culture lab. On the other end of the spectrum, it includes large tanks and associated pipelines, which may have capacities of several thousand gallons, such as are used in the dairy processing industry.

Efficient and effective techniques and apparatus for obtaining aseptic samples from such systems and enclosures, are particularly desirable. Examples of industries that require such aseptic sampling include, but are not limited to, the pharmaceutical, bioengineering/biotechnology, brewing/distilling, food processing and dairy processing industries. Applications for such samplings range broadly from process monitoring to laboratory and research applications. For example, sampling is commonly used on dairy farms for herd management or in regulated manufacturing facilities. The sampling is used to detect and control microbial contamination, spoilage microorganisms, food-borne illness, and environmental mastitis both within systems being sampled and externally of such systems. While preferred embodiments of this invention will be described with respect to its sampling use and application in the dairy industry, it will be understood that the invention is not to be construed as limited to use in that industry or to the application described, or to any limitations associated with the specifics of the components or methods disclosed with respect to such preferred embodiments.

Various methods and devices have been employed to perform sampling tasks. Typical sampling techniques commonly involve discrete or isolated sampling from a laminar portion of a fluid transport line. Typical such sampling systems and techniques that have been used in the dairy processing industry are described in U.S. Pat. Nos. 4,941,517; 5,086,813; and 5,269,350. To the extent that such patents may be used to assist the reader in understanding principles and examples of sampling apparatus and methods, they are herein incorporated by reference.

While the apparatus and techniques described in these patents are particularly applicable to systems designed to accommodate them, there also exists a need to perform sampling in existing enclosures and fluid transportation systems that have not been designed for sampling functions. Such systems typically require redesign or retrofitting to accommodate sampling functions. Such retrofitting can be expensive and/or difficult to achieve, can require significant system downtime in implementation of the sampling function and/or replacement of parts to maintain the system, or can lead to system degradation or contamination of the system being sampled. For example, one known method of discrete sampling of fluid involves inserting a needle through a sealing gasket located between connecting ends of pipelines of the fluid transportation system. Problems arises from this method as this method is not aseptic because the gasket becomes so perforated after repeated sampling that the gasket may lose its sealing integrity or introduce contaminants into the system through the perforations. This method requires that the gasket be replaced, which can become expensive both in labor costs and shut down costs.

There are many applications wherein it is desirable to obtain a continuous sample from fluid transportation systems or fluid processing enclosures. The discrete sampling methods typically extract a discrete sample size limited to the volume of a hypodermic needle and syringe. Typically the needle is inserted, fluid is drawn, and the needle is removed. It would be beneficial in some applications to have a system that could draw a continuous, controlled and constant sample volume over an extended period of time. A sampling device that facilitates this feature would also need to accommodate larger volume samples and a means to cool the sample during longer sampling time periods. While continuous sampling techniques have been tried, they have generally not been particularly effective, efficient or reliable in maintaining the aseptic condition of the system during the sampling interval.

Known discrete sampling techniques have not proven to be readily adaptable to continuous sampling techniques. For example, if the sample is taken from a region of laminar fluid flow, the sampling needle can create a venturi effect in the fluid flow being sampled, which can cause reverse flow siphoning from the collected sample and back into the sampled fluid. If such suction effect is disrupted by providing the sampling system with an air gap, the aseptic nature of the sampling system is compromised.

Improvement in methods and devices for sampling is needed, generally to better accommodate: ease of repeated continuous sampling of large volumes; structural integrity of fluid transport equipment; management of contamination; and convenience of continuous and controlled volume sampling. The present invention addresses these and other needs for continuous sampling of fluid transportation systems or fluid processing enclosures.

SUMMARY OF THE INVENTION

One aspect of the present disclosure relates to a method of monitoring quality of a fluid product. The method includes providing an aseptic sampling arrangement including a septum and a collection bag. A sample of the fluid product is obtained by aseptically collecting the fluid product in the collection bag. The collection bag is incubated for a period of time. The method also includes monitoring the level of contamination within the sample of fluid product during the period of time.

Another aspect of the present disclosure relates to a sampling arrangement for use with a fluid enclosure. The sampling arrangement includes a removable septum configured for receipt within an aperture of the fluid enclosure. The septum is constructed for penetration of a needle therethrough to provide fluid communication between an internal volume of the fluid enclosure and a collection bag. The sampling arrangement also includes a locking arrangement configured to provide selective access to the removable septum.

Yet another aspect of the present disclosure relates to a sampling arrangement having a septum, a securing element, and a locking arrangement. The septum is configured for receipt within an aperture of a fluid enclosure. The securing element configured to secure the septum within the aperture of the fluid enclosure. The locking arrangement includes a base, a cover, and a locking device, and is configured to provide selective access to the septum and the securing element.

Still another aspect of the present disclosure relates to a fluid system including a fluid enclosure, an aseptic sampling arrangement, and a locking arrangement. The aseptic sampling arrangement has a septum and a securing element, the septum being secured within an aperture of the fluid enclosure by the securing element. The locking arrangement provides selective access to the sampling arrangement.

And another aspect of the present disclosure relates to a method of providing access to a fluid enclosure. The method includes positioning a septum of an aseptic sampling arrangement within an aperture of the fluid enclosure and securing the septum within the aperture of the fluid enclosure with a securing element. The method further includes enclosing the septum and the securing element within a locking arrangement to prevent unwanted access to the septum and the securing element and locking the locking arrangement to permit only selective access to the septum and the securing element.

A variety of examples of desirable product features or methods are set forth in part in the description that follows, and in part will be apparent from the description, or may be learned by practicing various aspects of the disclosure. The aspects of the disclosure may relate to individual features as well as combinations of features. It is to be understood that both the foregoing general description and the following detailed description are explanatory only, and are not restrictive of the claimed invention.

DETAILED DESCRIPTION

This invention provides an apparatus and method for the continuous aseptic sampling of fluid material from a fluid transportation system or fluid processing enclosure5, schematically illustrated inFIG. 1. A fluid material6to be sampled is illustrated as flowing through a fluid line20by the fluid flow arrow designation “F”. A preferred sampling arrangement of the present invention is schematically illustrated at10and is depicted as operatively connected, by the dashed line8, to sample the fluid material6(as hereinafter described in more detail).

The principles described herein for the sampling arrangement10can be used in various industries and in various applications where aseptic sampling of material is desired. Aseptic sampling involves transferring fluids to or from process systems that are sensitive to contamination from the outside environment. For example, the pharmaceutical, bioengineering/biotechnology, brewing/distilling, food processing and dairy processing industries are in need of aseptic sampling technology. Such sampling technology can be applied broadly, the applications ranging from process monitoring to laboratory and research applications. For example, the fluid processing enclosure or fluid transportation system5illustrated inFIG. 1may comprise a dairy processing system used in the dairy industry. An example of one type of fluid processing enclosure or fluid transportation system5that has been used in the dairy processing industry is described in U.S. Pat. No. 5,269,350 and herein incorporated by reference. In such a system, the fluid material6therein may include raw milk or a processed milk product. The sampling arrangement10may be incorporated or retrofitted to the fluid transportation system5to provide continuous aseptic sampling for detecting microbial contamination or monitoring mastitis, coliform, food-borne illness bacteria, or spoilage bacteria in a dairy herd, for example.

While preferred embodiments of this invention will be described with respect to its sampling use and application in the dairy industry, it will be understood that the invention is not to be construed as limited to use in that industry or to the particular application described.

The Structural Components, Generally.

Referring toFIG. 2, the preferred sampling arrangement10depicted includes: an elbow12having flanges14and a port22; a least one septum or septum cartridge40(shown in phantom); a connecting conduit16; and a collection container18. In general, the sampling arrangement10comprises an arrangement that provides for a continuous draw of fluid from a flow F within a fluid line20, and deposits the fluid sample in the collection container18to provide the user with an accumulated process sample. It is to be understood that the fluid line20may comprise a variety of fluid transportation systems or fluid containment enclosures, and is not limited to pipe constructions. The collection container18may include a pouch, bag, reservoir, or other closed container of a typical construction and size, such as those used in the medical industry. In the illustrated embodiment, a medical type bag comprising a 2-liter collection pouch or bag is used. A variety of sizes and constructions of containers is contemplated.

As illustrated, the pipe segment or elbow12of the sampling arrangement10is in direct fluid communication with the fluid line20of the fluid transportation system. In accordance with the principles of the present invention, it is desirable to perform sampling from an area or region of non-laminar flow within the line20. The elbow12provides a turbulent or non-laminar flow region within its interior flow cavity by its non-linear configuration. It is to be understood that there are other means of creating a non-laminar flow region within the fluid flow line, such as having a protrusion or device extending into the flowing fluid within a substantially straight portion of the fluid line. Therein fluid turbulence or non-laminar flow is formed downstream of the extending device or protrusion. Creation of a non-laminar sampling region eliminates the problem of reversed fluid flow from the sample to the main fluid line, which commonly occurs in devices and methods of the prior art.

Referring now toFIGS. 3 and 4, the connection flanges14of the elbow12extend circumferentially at each end of the elbow12. The flanges14may include grooves (shown in phantom) sized to receive sealing gaskets (not shown) to seal the connections between pipe segments when installed in common fluid transportation line systems. In accord with the principles of the present invention, the sampling arrangement is generally adapted to be retrofitted within existing fluid lines of various fluid flow systems5(FIG. 1). Certainly the sampling arrangement10can be incorporated as original equipment into new installations of fluid transportation lines as well. Other means of connection or retrofit adaptation, including welding, are contemplated as a means of installation. The sampling arrangement is generally designed with standard plumbing components to facilitate retrofit modifications. It is to be understood that non-standard elements, such as non-standard pipe diameter, fittings, or material, are within the scope of the principles disclosed.

Preferably the elbow12is made of industry standard stainless steel, such as 304 or 316L stainless steel. Other materials applicable for use in the industry into which the sampling arrangement is implemented are contemplated. The elbow depicted inFIG. 3incorporates a standard 90-degree elbow. The angular configuration of the elbow will typically be a standard dimension within the range of 35 degrees to 180 degrees, typically 90 degrees. The preferred diameter of the elbow pipe is at least 1 inch, typically from about 1.5 to 3.5 inches in diameter.

The elbow12according to the present invention includes at least one aperture or port22. The elbow12may be located in any configuration in the fluid transportation system where the port22is operably in fluid communication with the fluid material6within the system. Thus, the interior angle of the elbow12may be oriented, for example, upward, downward or sideways in a fluid line arrangement. It is also contemplated that to ensure that the port is operably in fluid communication with the fluid material6, the port22may be configured in alternative locations on the elbow12. In the illustrated embodiment, the port22is located on the outer radius of the elbow12. Alternative embodiments may include, for example, an elbow having a port located on the interior radius of the elbow. Preferably, the port22is disposed at or within a non-laminar flow region of the elbow12.

As depicted inFIG. 3, the port22may include a transversely extending pipe portion or conduit26. The conduit26is sized to receive a septum cartridge40. The conduit26may include an externally threaded region28for purposes of securing the septum cartridge40. In one embodiment, the thread comprises a standard 1.5″-8 ACME thread corresponding to a mating internally threaded nut30. The threaded nut30may include an internal annular shoulder32(shown in phantom). The annular shoulder32acts as a bearing surface that engages a first surface46of the septum cartridge40(shown also inFIG. 7) to secure the septum cartridge in sealing manner when assembled within the port22. Other types of fasteners commonly used as securing or retaining means within this context are contemplated and may include, for example, a hex nut, a knurled lock nut, or a keyed nut.

Referring generally toFIG. 2, the septum cartridge40is in fluid communication with the interior cavity of the fluid line20by means of the aperture or port22in the elbow12. As shown inFIGS. 5-7, the septum cartridge40generally comprises a cap45, a central core member or boot49, and a plurality of guide holes48formed through the cap. For purposes of clarifying features, the septum cartridge40can be considered to have a top41and a bottom42.

The cross-section of the boot49is seen to increase progressively from the bottom42toward the top41of the septum cartridge40. The boot49is sized such that when the boot is placed within the port22of the elbow there is compressive contact between the interior surfaces defining the port22and the boot49. The boot thereby functions as a sealing member. The boot49illustrated is generally conical, but could adopt a variety of shapes as will be obvious from the following discussion of the functioning of the septum cartridge in combination with other components of the invention.

The boot49may be made of material that is generally considered to be of a rubber compound. While compounding of an acceptable rubber composition is believed to be within the skill of the rubber molding art, it is found that rubber compounds based on ethylene propylene diene monomer terpolymer (EPDM) are particularly advantageous, having suitable sealing characteristics. EPDM is a known elastomer, and recognized by those skilled in the polymer arts. Other elastomers are contemplated, such as those derived from, or modified with, butene isoprene, ethylene, and the like. In an alternative embodiment, the boot may comprise a silicone compound. Silicone also provides suitable sealing characteristics. Materials such as Viton or other FDA approved elastomers are also contemplated for use in manufacture of the boot.

Preferably, the cap45includes an annular radially extending portion34defining the first upwardly oriented surface46and an opposing second lower surface47. The outer diameter of the annular portion34is preferably only slightly less than the inner diameter of the internal shoulder32on the threaded nut30for purposes of engaging and retaining the septum cartridge40within the port22of the elbow in the sampling arrangement10.

The cap45is made of a material that is normally not penetrable by conventional hypodermic needles. A typical material for fabrication of the cap may include one of the engineering plastics, such as nylon, polypropylene, or high-density polyethylene. The penetrability of the septum cartridge40is thus provided by one or more of the integrally formed guide holes48, which begin from a top surface43of the cap45and extend downwardly through the cap45.

The guide holes48are integral with the cap45and located to correspond to the boot49. The guide holes48extend downwardly through the cap structure45and are oriented and positioned so that a sampling needle50(shown inFIG. 8) may pass through the guide hole48and into the boot49. The guide holes48are generally sized to be only slightly larger than the needle, such that the needle slidably fits snugly within the guide hole, preferably without substantial friction, but with a close enough fit to ensure that the guide hole provides direction to the needle as it is inserted through the boot. In one embodiment (FIG. 5), the septum cartridge40aincludes seven guide holes. In another embodiment (FIG. 6), the septum cartridge40bincludes twelve guide holes. Typically the septum cartridge includes at least one guide hole, generally 1 to 15 guide holes.

A cover film60covers the top surface43of the cap45, including the guide holes48formed in the top surface43of the cap45. The cover film60easily identifies used holes to reduce the risk of contamination from reinserting a needle into a previously used guide hole. The cover film60may be made from any readily pierceable film material. A typical film material is a vinyl tape having an adhesive coating to securably attach the cover film60to the top surface of the cap45.

Referring toFIGS. 2 and 8, the penetrating body or needle50is in fluid communication with the connecting conduit16, and the connecting conduit16is in fluid communication with the collection container18. In the preferred embodiment, the needle comprises a beveled end51having an aperture52that defines a hollow portion running longitudinally through the needle50. It is to be understood that other penetrating bodies, such as lumens, hollow members, or inserting devices may be used in accordance with the principles disclosed.

In use, the needle50penetrates the cover60, passes through a selected guide hole48, and penetrates through the boot49. As the needle penetrates the boot, the needle displaces the elastomeric/rubber material of the boot which forms a fluid impenetrable seal about the needle. The beveled end51of the needle50progresses through the boot49and emerges from the boot at the bottom42of the septum cartridge40. The needle therein enters into the flow of fluid F.

The needle50is sized and adapted for use with the septum cartridge40. Typically the needle comprises a 12 gauge to 22 gauge needle, preferably a 16 gauge needle. The needle generally has a length of from about 1.0 inches to 4.5 inches. Preferably the needle is at least 1.5 inches in length if the port22is bottom placement oriented and at least 2.0 inches if the port22is top placement oriented. What is meant by top and bottom placement oriented is how the sampling port is oriented with respect to ground. Thus, if the elbow is top placement oriented, a longer needle50is needed to ensure the needle aperture52is submerged within the fluid material when operatively inserted through the septum40.

Still referring toFIG. 2, the connecting conduit16also includes sealing ends62at locations where the fluid flow transitions from the needle50to the connecting conduit16and from the connecting conduit16to the collection container18. A typical, usable connecting conduit is the type used by the medical industry in fluid administration sets. Conduit in accordance with the principles disclosed includes, for example, tubing, flexible piping or flexible lumen constructions that provide closed, aseptic fluid communication between ends.

Preferably the connecting conduit16is of sufficient length to reach from the elbow12to an area where the collection container18is placed. The length may thus vary and typically falls within the range of 5 inches to 65 inches, and preferably is about 38 inches in length. In one embodiment, the connecting conduit comprises a 0.121 inch inside diameter and a 0.166 outside diameter. It is to be understood that typical fluid administration sets having a needle, connecting conduit, and a collection pouch are contemplated for use in this sampling arrangement.

In use, the needle50is inserted through the septum40into a non-laminar fluid flow region of the elbow12. Sampling at a non-laminar fluid flow region addresses the problem of reversed fluid flow often created by a venturi effect of prior sampling systems. The venturi effect is created where the velocity of the laminar fluid flow flowing past an orifice or tube opening (such as in a needle) causes a corresponding decrease in fluid pressure, which creates a siphoning or suction. Thus, instead of drawing sampled fluid from the fluid line into a collection container, sampled fluid is actually drawn from the collection container back into the fluid line. The sampling arrangement10of the present invention reduces or eliminates this problem.

Some Selected Alternate Embodiments

Alternative embodiments incorporating the principles of the present invention will be apparent from the description below and in the context of the illustrations inFIGS. 2 and 9.

In one alternative embodiment, the sampling arrangement10includes a flow restricting device. The flow restricting device may comprise a clamp64as shown inFIG. 2. The clamp64compressively engages the outer surface of the connecting conduit16and is adjustable such that flow through the tube may be restricted to a desired flow rate. Thereby, the continuous sampling rate may be increased or decreased during sampling as needed.

Another embodiment of the sampling arrangement includes an alternative means of regulating flow.FIG. 9depicts a fragmented portion of a sampling arrangement including a metering or peristaltic pump68. The peristaltic pump68cooperatively engages connecting conduit16and is adjusted as is known in the art to provide a desired regulated flow rate.

The clamp64and the peristaltic pump68are products of common manufacture. The clamp may comprise any clamping device suitable to provide restriction in the connecting conduit16. The peristaltic pump may comprise, for example, a variable flow pump having a medium flow rate of 4.0 to 85.0 milliliters per minute. Specifically, a Medium Flow variable flow pump, Model Number 54856-075, manufactured by MASTERFLEX is one variable flow pump that may be used.

Yet another embodiment of the present invention provides for cooling of the extracted sample held by the collection container. If it is desirable to keep the extracted sample cool during collection, the collection container18may be placed in an insulated cooler70surrounded by ice or cold packs as shown inFIG. 1, for example. Common coolers can be modified to include a hole72in the top or lid through which the connecting conduit16can be routed.

FIGS. 10-13illustrates still another embodiment of the present invention including a tamper-resistant locking arrangement80. As previously described, the disclosed sampling arrangement10is coupled to the fluid processing enclosure or fluid handling/transport system5. In this particular application, the fluid transport system5includes, for example, a tank82. The tank may be any type of fluid-containing tank, such as the fluid processing enclosures5previously described, storage tanks, and even over-the-road transportation tanks, such as a tanker truck, for example. The locking arrangement80is useful in any application where product tampering or product removal may be of concern. The locking arrangement80is also useful in locations or processing areas that are less frequently monitored.

As shown inFIGS. 10-13, the locking arrangement80generally includes a base102, a cover84and a locking device86(FIG. 13). The locking arrangement80is configured to enclose the threaded nut30and septum cartridge40(FIGS. 5-7) of the sampling arrangement10to prevent unwanted access to the internal volume of the tank82.

Referring now toFIG. 11, a hole104is formed in the base102of the locking arrangement80. In use, the base102is positioned at a conduit126of the tank82. As previously described, the conduit126is sized to receive the septum cartridge40(seeFIG. 3). In the illustrated embodiment, the conduit126includes a shoulder106upon which the base104sets. An externally threaded region (shown for example inFIG. 3) of the conduit126extends through the hole104of the base102. The threaded nut30of the sampling arrangement10is threaded onto the externally threaded region for purposes of both securing the septum cartridge40within the conduit126and capturing the base102between the nut30and the shoulder106of the conduit126.

The cover84of the locking arrangement80is then positioned over the threaded nut30. As shown inFIGS. 10 and 11, the cover84is sized to fit between opposing sides108and opposing brackets92of the base102. The opposing sides108and the opposing brackets92of the base102extend outward from a main portion110(FIG. 12) of the base102. In the illustrated embodiment, the sides108are shorter than the brackets92. In use, the sides108aid to position the cover84in relation to the base102so that the cover84is retained between the opposing sides108of the base102. The opposing brackets92are configured to extend outward from the main portion110of the base102beyond the cover84when positioned assembled as shown inFIG. 13. Each of the brackets92includes a hole94(FIG. 11) that receives a rod98(FIG. 13) of the locking device86.

Referring toFIG. 13, when the rod98of the locking device86is positioned through the holes94of the brackets92, the rod98extends across the top of the cover84so that the cover84cannot be removed. Because the cover84cannot be removed, the top41of the septum cartridge40cannot be accessed; similarly, the threaded nut30cannot be accessed. In addition, the main portion110of the base102also prevents access to the threaded nut30. As can be understood a lock100, such as a combination lock or key lock, is coupled to the rod98to secure the locking device86and prevent unwanted access to the septum cartridge40, the threaded nut30, and the fluid contained within the tank82. To access the septum cartridge, the locking device86is unlocked, and the cover84is simply removed.

Although the locking arrangement80has been described with respect to a tank application, it is contemplated that the locking arrangement80can further be used in pipe system applications, such as the application shown inFIG. 2, or other fluid transport systems and processing enclosures.

The alternative embodiments herein described may be used in combination with each other or used independent of one another.

The Method of Continuous Sampling, Generally.

In operation, the elbow12is installed at a convenient sampling location along a fluid line20. The elbow is preferably oriented such that the port22is in direct fluid contact with the material transferred within the fluid line, to reduce the potential of air drawn during sampling.

The boot49of the septum cartridge40is placed into the sampling port22until the second surface47of the cap45rests against the outer edge of the sampling port22. The securing nut30is installed onto the conduit of the port22to sealingly, operatively secure the septum within the port.

For aseptic sampling, the sampling arrangement, including the port, nut, septum cartridge, etc, are sanitized with a common alcohol prep or other sanitizer. In particular, aseptic sampling is optimized when the cover film60is cleansed with a disinfectant, and a sterilized needle50is inserted through the disinfected cover film, through an unused guide hole, and through the septum boot.

The needle is preferably directed or slanted toward the center of the septum boot at insertion. This provides greater assurance that the needle penetrates through the entirety of the boot. In effect, the boot essentially squeegees or cleanses the needle of any contaminants missed during initial aseptic disinfectant processes. Directing the needle toward the center of the boot also reduces the possibility of contacting the wall of the extended portion of the elbow.

The needle may be oriented such that the beveled end51faces toward the flow of the fluid material to aid in fluid sampling. A pressure differential is applied between the collection container and the fluid line to effect the fluid sampling or material transfer. The pressure differential may be applied in a number of ways. One way is by introducing pressure into the fluid line. Another is by reducing pressure in the connecting conduit or collection container. Any means of generating an adequate pressure differential between the fluid line and the collection container is effective to cause the flow of material through the needle. Other methods of applying the pressure differential and thus effecting the transfer of a sample will be obvious to those skilled in the art.

Material from a tank, for example, thus flows from the fluid line20, through the needle50, and into the collection container18by way of the connecting conduit16. In one alternative application, the collection container may be placed into a cooling container70of ice or ice water, for example, to reduce or eliminate bacterial growth during the sampling process.

The flow from the fluid line20to the collection container18may be adjusted to a particular flow or sampling rate by means of the clamp restriction. The flow may likewise be metered wherein the peristaltic pump is assembled to the connecting conduit to regulate the flow.

When the desired sample has been collected, the collection container is removed from the connecting conduit16and sealed. The needle50is removed from the septum cartridge40. As the needle end is withdrawn, the material of the boot49withdraws into the position held prior to needle penetration. The boot49of the septum40thus closes and seals the passageway of the now removed needle.

After performing a number of sampling procedures, so that all guide holes have been used, the septum cartridge40is removed and discarded. The punctured cover film60provides a ready indictor of those guide holes that have been used. A new septum cartridge easily replaces the used septum cartridge for future samplings.

Some Selected Alternate Methods of Use

Once a sample has been collected, the collection container18of the present invention may be used to determine any number of product quality defects. One use for determining product quality defects applies to the dairy industry; in particular, to detecting quality defects in dairy fluid products, such as milk, for example.

One such defect is post-pasteurization contamination (PPC). There are many sources of post-pasteurization contamination including inadequate cleaning and sanitizing, contaminated water, engineering defects such as cracked tanks or other equipment components, condensation in compressed air lines, and other sources. Undoubtedly contamination from these sources can result in poor keeping quality, consumer complaints, and reduced profits.

One of the primary causes of dairy product quality defects is post-pasteurization contamination (PPC) with gram-negative psychrotrohic bacteria found in pasteurized milk. In recent years, research has shown that the level of post-pasteurization contamination of gram-negative bacteria in pasteurized milk can be extremely low, but still affect dairy product quality. This research showed that contamination rates as low as one bacterium per liter can cause spoilage and other product defects in a short time if the growth rate of that bacterium is extremely fast. Other research has shown that the growth rate is dependent on storage temperature and oxygen concentrations of the milk. For example, it is possible for gram-negative bacteria to cause quality defects at 7° C. (45° F.) in a little as ten days under ideal growth conditions of saturated oxygen in milk.

The disclosed sampling arrangement10can be used to effectively monitor dairy processes for the potential of contamination of the gram-negative psychrotrophic bacteria. In particular, to monitor for possible gram-negative bacteria contamination, the arrangement10is used to obtain an aseptic fluid sample within the collection container18at the discharge of the HTST (High Temperature Short Time) pasteurizing processor. Because of the aseptic design of the sampling arrangement10, contamination of both the fluid sample and the primary fluid flow during sampling is prevented to preclude the sampling arrangement as a source of bacterial contamination. Typically, the size of the fluid sample is between about 50-500 ml in volume, however, the collection container18can aseptically accommodate larger samples of up to about 5 liters.

In one embodiment, the collection container18preferably has an oxygen permeability that simulates the level of oxygen to which the fluid product is exposed. For instance, the oxygen permeability preferably simulates the oxygen saturation associated with pre-packing operations and the product packaging within which the fluid will be stored. By this, the collection container18allows gram-negative bacteria to grow in the same fashion as the bacteria would in product storage containers. In particular, the oxygen permeability of the collection container18promotes the same growth rate of contaminate as there would be in a product that has been fully oxygen saturated through pumping, agitating and filling procedures. The arrangement10thereby simulates the storage conditions for purposes of monitoring for gram-negative bacteria without the addition of air or oxygen to a collected sample.

Once the desired fluid sample size is collected, the sample is permitted to incubate for a time period sufficient to allow for low-level contaminants to reach a level that can be counted by conventional laboratory procedures. Typically, the incubation period corresponds to the shelf life of the fluid product. In one method, for example, the fluid sample is incubated for a number of days at 45° F. During the incubation period, oxygen permeates the collection bag to oxygenate the fluid product. A Standard Plate Count is conducted during the incubation period to determine the level of gram-negative bacteria present within the sample. The Standard Plate Count can be repeated any number of times during the incubation period. Methods other than the Standard Plate count for detecting psychrotrophic bacteria (spoilage bacteria) can be used.

To illustrate the oxygen permeability of the collection bag18, a study of gram-negative psychrotrohic bacteria was conducted at the University of Minnesota's Biological Technology Institute. In this study, a fluid sample of sterilized milk was inoculated withpseudomonasbacteria at a population of about 60 organisms per liter. The inoculated milk was filled in three collection bags and three 60 cc syringes, and then incubated in the refrigerator at 7° C. (45° F.). The three syringes containing inoculated milk served as non-permeable container controls. Bags and syringes containing un-inoculated milk also served as controls (see Table 1 below). In the inoculated collection bags, the presence of the bacteria was clearly evident with six days. In contrast, the inoculated syringes required 21 days to positively confirm the presence of bacteria. By using the disclosed sampling arrangement10, the time needed to obtain contamination results is significantly shortened due to the oxygen permeability feature of the collection bag18. Reducing the time needed to detect contamination saves in production costs and reduces product waste associated with continued production of a contaminated product.

Another defect affecting the quality of dairy fluid products is spore-forming bacteria found in pre-pasteurized or raw milk. Raw milk quality can greatly influence the keeping quality of market milk. One of the primary causes of spore-forming bacteria is gram-positive psychrotrohic bacteria. Spore-forming bacteria is generally caused by contamination introduced in pre-pasteurization milk processes. Determining the level of spore-forming bacteria in a fluid product sample provides valuable information for evaluating the associated production, cleaning processes and shelf life.

Research has also shown that the level of spore-forming contamination of gram-positive bacteria in raw milk can be low, but still affect dairy product quality. For instance, spore-forming bacteria has been found to survive heat treatments of up to 176° F. at 10 minute intervals. In fact, the heat treatment in some cases has even activated spore germination and outgrowth in milk. The disclosed sampling arrangement10can be used to effectively monitor dairy processes for the potential of contamination of the gram-positive psychrotrophic bacteria.

In particular, to monitor for possible gram-positive bacteria contamination, the arrangement10is used to obtain an aseptic fluid sample within the collection container18. Because of the aseptic design of the sampling arrangement10, contamination of both the fluid sample and the primary fluid flow during sampling is prevented to preclude the sampling arrangement as a source of spore-forming bacteria contamination.

Spore-forming bacteria is inherent in raw milk, however, an excessive amount of spore-forming bacteria, or the presence of spore-forming bacteria that has an accelerated growth rate is undesirable and will most likely result in unacceptable milk quality at refrigeration temperature. The collection container18of the present sampling arrangement10has an oxygen permeability that provides a level of oxygen saturation that accelerates the growth rate of spore-forming bacteria. By this, the collection container18allows gram-positive bacteria to grow in an accelerated fashion to determine the amount of gram-positive bacteria present.

Once the desired fluid sample size is collected (e.g., up to 5 liters), the sample is permitted to incubate for a time period sufficient to allow for the spore-forming contaminants to grow. For example, in one method, the fluid sample is incubated for a period of time approximate to the standard product shelf life, e.g., 18-24 days, at 45° F. During this period, oxygen permeates the collection bag to oxygenate the fluid product. A conventional laboratory procedure, such as a Standard Plate Count, is then conducted after the period of time to determine the level of gram-positive bacteria present within the sample. A level of gram-positive bacteria greater than 10,000,00 counts/ml, for example, would indicate that the spore-forming bacteria present has the potential for causing product quality defects. This information can then be used to re-evaluate production and cleaning process to reduce the likelihood of future quality problems.

To illustrate the oxygen permeability of the collection bag18, a study of gram-positive psychrotrohic bacteria was conducted at the University of Minnesota's Biological Technology Institute. In this study, a fluid sample of raw milk was collected in the disclosed bag. The bag was incubated for 18-24 days at a temperature of about 7° C. (45° F.). A standard plate count was then conducted. Using gram-stain procedures, the samples having bacteria counts of greater than 10,000,000/ml were identified (see Table 2 below). Identifying the samples having high bacteria counts reduces product waste associated with continued production of a contaminated product.

The above specification, examples and data provide a complete description of the manufacture and use of the invention. Many embodiments of the invention can be made according to the disclosed principles.