NZ582006A - Apparatus for microbiological testing with retention device holding test tube in inverted position within a container - Google Patents

Abstract

The testing apparatus 500 has a retention device 300 which retains test tube 200 in an inverted position within container 400.

Description

PATENTS FORM NO. 5 Fee No. 4: $250,00 PATENTS ACT 1953 COMPLETE SPECIFICATION After Provisional No: 582006 Dated: 15 December 2009 APPARATUS FOR MICROBIOLOGICAL TESTING I Peter Bailey, a New Zealand citizen of 8 Micawber Place, Howick, Auckland 2014 hereby declare the invention for which I pray that a patent may be granted to me, and the method by which it is to be performed to be particularly described in and by the following statement: Received by IPONZ 9 May 2011 APPARATUS FOR MICROBIOLOGICAL TESTING TECHNICAL FIELD This invention relates to an apparatus for microbiological testing. More specifically, the invention relates to an apparatus including a test tube and retention device for 5 insertion into a container.

BACKGROUND ART Microbiological testing is widely used throughout many industries, such as the food industry, oil and gas, pharmaceuticals and cosmetics. Screening for microorganisms in a product is essential at various stages throughout production, 10 particularly for products that are designed for human use or consumption. Failure to accurately detect a microorganism in a product can result in outbreaks of disease and sickness, and consequent financial losses for those involved in the supply chain.

One of the more commonly used methods for detection of microorganisms is the 15 use of an inverted durham tube placed within a larger test tube or vial. A specific enrichment broth is added to the tube or vial and the air expelled out of the durham tube by inversion, boiling, autoclaving or gamma irradiation.

Microorganisms present within the vial produce gases which are collected within the inverted durham tube. The presence of a gas bubble is an indication that a 20 specific type of microorganism is present. The by-products of fermentation that are produced along with the gas may also react with the substance being tested and result in colour changes of the product within the vials.

The preparation for such a microbiological test can be both manually intensive and time consuming. Typically, durham tubes are individually placed within a larger vial 1 Received by IPONZ 9 May 2011 or test tube. The vials then need to be autoclaved or sterilised and filled with the enrichment broth ready for testing. Once the test has been completed, the vials and durham tubes are separated, rewashed and sterilised ready for reuse. Given the fragility and small size of a typical durham tube, such a cleaning and 5 sterilisation process is not efficient. As well as being somewhat difficult to clean, there are risks that the durham tubes can be broken either during washing or in use, posing both a safety risk for the user and an expense for the company.

A number of parties have attempted to overcome these disadvantages in a variety of ways.

JP2003230375 discloses a plastic durham tube. This invention goes some way to addressing the problems associated with fragile glass tubes, however it does not address the problems associated with the amount of manual labour required to prepare for and clean up from such testing processes.

Canadian Patent No. 1264434 discloses a bacterial fermentation testing kit which 15 is designed to eliminate the need for the sterilisation, pressure treatment and cooling off period normally required before using a durham tube. It also eliminates the need for inversion of the tube to remove any air bubbles. The apparatus disclosed includes a tube that is open at both ends, and has a constricted neck portion that can be sealed by a cone shaped plug pushed into the neck portion of 20 the vial. This tube can be located either internally or externally of a larger tube or vial.

The tube described in CA 1264434 removes some of the labour required when preparing testing kits for use. It does however introduce further small parts which are both fragile and difficult to clean. The additional moving parts required to 25 operate the device are also likely to increase the cost of manufacturing and purchasing the apparatus. 2 Received by IPONZ 9 May 2011 It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.

It is a further object of the invention to provide a testing apparatus that performs the same function as an inverted durham tube within a vial, but reduces the 5 amount of labour involved in preparing and cleaning up the individual pieces of apparatus.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their 10 authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.

Throughout this specification, the word "comprise", or variations thereof such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.

DISCLOSURE OF THE INVENTION According to one aspect of the present invention there is provided a microbiological testing apparatus adapted for attachment to a container, the apparatus including; • a test tube; and 3 Received by IPONZ 9 May 2011 • a retention device associated with the test tube; wherein the retention device is adapted to fixedly retain the test tube in an inverted position within the container.

According to another aspect of the present invention there is provided a kit for 5 microbiological testing, the kit including; • a container; and • an apparatus adapted for attachment to a container, wherein the apparatus includes; a test tube; and - a retention device associated with the test tube, wherein the retention device is adapted to fixedly retain the test tube in an inverted position within the container.

In preferred embodiments, the test tube and retention device are integrally formed.

In an alternative embodiment, the test tube is releasably connected to the retention 15 device.

In further preferred embodiments, the retention device is fixedly retained within the container by biasing against a side wall or walls of the container.

Preferably, the retention device substantially corresponds to the shape of at least a part of the container wall or walls.

More preferably, the retention device is substantially the same height as the container wall or walls. This allows for the apparatus to be constrained vertically within the container and to maintain the apparatus in a preferred position. 4 Received by IPONZ 9 May 2011 In alternative embodiments the height of the retention device is substantially less than that of the container wall. This embodiment is particularly suited to apparatus that are held in position within the container by biasing against the walls of the container.

In further preferred embodiments, the apparatus is made from transparent polycarbonate plastic As will be clear to a person skilled in the art, the apparatus and container of the present invention need to be at least partially transparent or be formed from a material that becomes at least partially transparent under certain conditions, e.g. UV light. The contents of the test tube and container must be able 10 to be easily viewed, and a positive or negative test confirmed by viewing the presence or absence of a gas bubble within the test tube.

More preferably, the polycarbonate plastic is high clarity, non auto-fluorescing polycarbonate plastic. While polycarbonate is a preferred material from which to manufacture the apparatus of this invention, it is not intended to be limiting. The 15 apparatus may also be formed from material such as polypropylene, glass, or other suitable plastics or transparent materials known to those skilled in the art that are capable of withstanding a range of temperatures and pressures as may be required during sterilisation and/or testing procedures.

In alternative embodiments, the retention device is in the form of a lid. When 20 supplied as a kit, the lid is of the correct size to securely fit the container provided with the kit, holding the test tube in position with the container.

In preferred embodiments, the apparatus will be manufactured to be used with pre-purchased or standard containers or vials.

In further preferred embodiments the apparatus is manufactured using the 25 following steps; Received by IPONZ 9 May 2011 • preparing a die in the shape of the apparatus; • forming the apparatus from the die using a moulding process.

In alternative embodiments the apparatus may be manufactured using the following steps; s • preparing a first die in the shape of the test tube; • preparing a second die in the shape of the retention device; and • forming the test tube and retention device from the first and second dies using a moulding process.

In more preferred manufacturing methods, the moulding process used is injection 10 moulding or blow moulding.

More preferably the moulding process used is multi-cavity injection moulding.

Throughout the specification the term "test tube" should be taken to mean any container and vial that is open at a first end and closed at a second end. The term "test tube" is not intended to limit the apparatus to a tubular shape and may refer 15 to, for example, a "test tube" that has one or more flat surfaces (for example where it is formed with the retention device). The standard "durham tube" known in the art of microbial testing is one example of a test tube that is preferably used. The majority of the test tubes to be used in the current invention are small tubes, approximately between 30 - 70mm long however it will be understood that test 20 tubes of any size may be used if required for a particular test or use. It will also be understood by a person skilled in the art that the test tube will need to be either at least partially transparent so any gas bubble collected within the tube is visible. Alternatively, the test tube may be formed from a material that will allow the gas bubble to be detected under certain conditions, for example UV light. 6 Received by IPONZ 9 May 2011 The term "inverted" should be given its standard meaning, whereby an "inverted test tube" describes a tube that has the opening of the tube facing downwards. When in a container, an inverted test tube has the opening facing towards the sealed base of the container.

The term "retention device" should be taken to mean any device that is capable of being inserted within or attached to a container and which has the purpose of retaining the test tube in a set position/orientation. While the retention device of the present invention is preferably shaped to fit against a side wall (or walls) of a container, this is not intended to be limiting. For example, the retention device may 10 be in the form of a ring encircling the interior of a container, a clip attached to the container wall, or any other device that can be fixedly retained within the container and act to hold the test tube in a desired position/orientation. As described in an alternative embodiment below, the retention device may be a lid of a container, to which the test tube is attached. The test tube is then held in a fixed position within 15 the container once the lid has been screwed or placed on the top of the container.

A "container" of the present invention means any vial, vessel or other container that may be used to hold a medium for microbiological testing. The container may be of varying sizes and formed from a range of different materials as would be deemed suitable by a person skilled in the art.

It is also envisaged that the container may be fitted with a range of different lids, such as a screw cap, or friction fit cap.

BRIEF DESCRIPTION OF DRAWINGS Further aspects of the present invention will become apparent from the following description which is given by way of example only and with reference to the 25 accompanying drawings in which: 7 Received by IPONZ 9 May 2011 Figure 1 shows a perspective view of a microbiological testing apparatus in a preferred form of the invention; Figure 2 shows a side view of the testing apparatus shown in Figure 1; Figure 3 shows a top view of the testing apparatus shown in Figures 1 and 2; Figure 4 shows a perspective view of a container for use with the preferred embodiment of the invention depicted in Figures 1-3; Figure 5 shows a side view of the container shown in Figure 5, with the apparatus of Figures 1 to 3 inserted within; Figure 6 shows a top view of the container of Figures 4 and 5, with the apparatus of Figures 1 to 3 inserted within.

Figure 7 shows a perspective view of a testing apparatus inside a container in a further preferred form of the invention.

Figure 8 shows a perspective view of a testing apparatus in an alternative form of the invention.

Figure 9 shows a side view of a container in use with the alternative form of the testing apparatus shown in Figure 8.

BEST MODES FOR CARRYING OUT THE INVENTION The invention of the current application is described below with reference to the Figures and the preferred embodiment.

Figures 1 to 3 show a microbiological testing apparatus 100 in a preferred form of the invention. Apparatus 100 includes a test tube 200 and retention device 300. 8 Received by IPONZ 9 May 2011 Tube 200 and retention device 300 are preferably made from high clarity, non auto-fluorescing transparent polycarbonate plastic. A high clarity, transparent polycarbonate plastic is preferable as this allows for any gas bubble formed within tube 200 to be clearly visible through both retention device 300 and the wall of a 5 transparent container (or transparent wall section of a container) or vial in which the apparatus 100 is placed. It is envisaged that apparatus 100 may be used in testing procedures that require examination of the test samples under a UV light. Tube 200 and retention device 300 are therefore preferably non auto-fluorescing so as to not interfere with or influence any testing procedure conducted under UV 10 conditions. It should also be understood that tube 200 and retention device 300 will be made from materials able to withstand a number of different sterilisation environments, such as autoclaving, gamma irradiation or high temperature sterilisation.

Tube 200 is preferably in the form of a standard durham tube, with a rounded, 15 closed first end 201 for gas collection (best seen in Figure 2) and an open second end 202 which allows for entry of a medium to be tested into tube 200. Tube 200 may be formed in a wide range of different sizes suitable for a range of testing applications; however it is essential that the tube be of sufficient diameter to receive a gas bubble formed through fermentation/metabolic activity within the 20 testing medium. Preferably tube 200 is greater than 5mm in diameter, as a tube with a diameter of less than 5mm will potentially not provide a space large enough for a gas bubble to form within.

Tube 200 must also be of a size that can easily be retained within a container (for example container 400 as shown in Figures 4 and 5) without being obscured from 25 sight, for example by lid 401. Tube 200 is also retained above the base of container 400 such that any medium introduced into container 400 will easily enter tube 200 at open end 202. The collection portion (closed first end 201) of tube 200 9 Received by IPONZ 9 May 2011 is preferably retained just under the surface of the liquid medium.

Tube 200 is held in the preferred position as described above within container 400 by retention device 300. Retention device 300 is adapted to substantially correspond to the shape and dimensions of wall 402 of container 400 as shown in 5 Figures 5 and 6. Retention device 300 is preferably formed from a substantially rigid, resilient material. It will be appreciated by those skilled in the art that such material is capable of being deformed slightly under compression force in order to aid insertion into container 400, but will revert to its original configuration once the compression force has been released.

In preferred embodiments (as shown in Figures 1-3 and additionally in Figure 7) retention device 300 is formed from a curved wall of high clarity, transparent polycarbonate plastic and is of a radius slightly larger than that of container 400 in to which it is to be inserted. In one example of the invention container 400 has an internal radius of 9mm and retention device 300 is formed from a curved wall with a 15 radius of 9.5mm. To insert retention device 300 into container 400 (as shown in Figure 5) side walls 301 and 302 of retention device 300 are compressed (for example by hand) in the direction of arrows B (Figure 1) and retention device 300 is slid under compression into container 400. Once the compressive forces are released, side walls 301 and 302 return to their original configuration and so exert 20 a compressive force against the inside walls of container 400, fixing retention device 300 in position within the container.

Retention device 300 is preferably of such a size that when inserted, the base 303 of device 300 rests against the internal base of container 400 holding tube 200 at a set vertical position away from the base wall of container 400. Regardless of the 25 overall height of device 300, base 303 constrains tube 200 at a vertical position above base 303 that enables successful collection of gases. This requires tube 200 to be above the base of container 400 such that testing medium is able to enter Received by IPONZ 9 May 2011 tube 200, and low enough that tube 200 is not held above the upper level of the testing medium once added to container 400. It is envisaged that apparatus of a number of different sizes will be made available to suit a range of different containers and volumes of testing mediums. In preferred embodiments upper rim 5 304 of device 300 also substantially aligns with the upper rim of container 400. This ensures that when lid 401 is attached to container 400 there is little or no room for vertical movement of retention device 300 within container 400. This embodiment is suitable for use in testing methods where container 400 and insert 100 will be autoclaved with the medium before use.

While it is preferable for retention device 300 to reach the upper rim of container 400, in alternative embodiments upper rim 304 of the retention device 300 may not reach the upper rim of container 400. As discussed earlier, if autoclaving is used there is no requirement for the container to be inverted before use. This removes the need for insert 100 to be held directly against lid 401 of container 400. The use 15 of such smaller insert 100 may reduce costs, particularly when container 400 is relatively elongate.

In the preferred embodiments shown in Figures 1-7, tube 200 and retention device 300 of insert 100 are integrally formed using injection moulding, blow moulding or such other suitable moulding techniques as would be known to a person skilled in 20 the art. Preferably multi-cavity injection moulding will be used in order to produce large quantities of insert 100 in a cost effective manner. This is not intended to be limiting however. Tube 200 and retention device 300 may also be separate components connected to each other via a click-fit mechanism, an interference fit mechanism, glued into position using an adhesive and the like.

Preferably tube 200 is formed on or attached to retention device 300 along axis A as shown in Figure 1, forming apparatus 100. This will ensure that when apparatus 100 is inserted and retained in container 400, forming kit 500, tube 200 11 Received by IPONZ 9 May 2011 will be oriented in a substantially vertical alignment within container 400. Tube 200 is also preferably formed or attached approximately halfway between base 303 and upper rim 304 of retention device 300, allowing a clear view of the contents of tube 200 from the exterior of container 400 and egress of gas into tube 200 via open 5 end 202 (as previously described).

In use, apparatus 100 is inserted into container 400 such that open end 202 of tube 200 is facing the base of the container, allowing gas to rise and be collected at the top of tube 200, in known fashion.

Container 400 preferably includes a lid 401. Once container 400 is filled with a 10 medium to be tested, attachment of lid 401 further retains apparatus 100 in position and seals the medium inside the container. The sealed container can then be inverted and/or sterilised ready for the test to occur.

Figures 8 and 9 show an alternative embodiment of the invention. Apparatus 600 is formed by attachment of tube 601 to an inside surface of a retention device in 15 the form of a lid 602. By attaching tube 601 to the inside of lid 602, tube 601 is automatically inserted within a container (603, Figure 8) ready for use in testing when lid 602 is attached to container 603. As with the preferred embodiments shown in Figures 1-7, tube 601 is preferably made from transparent material, and is positioned such that when apparatus 600 is placed within container 603, tube 20 601 is held next to the side wall of container 603 and is clearly is visible from the exterior of container 603. Tube 601 houses inner tube 601 A, which acts as the collection vessel for gases released from a medium placed within container 603. The top 601B of inner tube 601A is located below the lower rim of lid 602 so any gas collected near top 601B is visible through the outer wall of container 603.

The attachment of tube 601 to lid 602 can be performed by any means suitable as would be understood to a person skilled in the art and as discussed in relation to 12 Received by IPONZ 9 May 2011 the preferred embodiments of the invention above. For example, using injection moulding, adhesives, click-fit mechanisms etc.

As would be clear to a person skilled in the art, having top 601A of tube 601 located above the lower rim of lid 602 would make viewing difficult. To overcome 5 this problem lid 602 could be made from transparent material, for example polycarbonate plastic, so that the user would be able to detect the presence or absence of a gas bubble within tube 601. Placing tube 601 near the top of container 603 would require a greater amount of sample to be added to container 603 in order for the sample to reach tube 601.

Locating top 601A of tube 601 below lid 602 is therefore more preferable. Lid 602 may then be made from any suitable material as it will not be necessary for the lid to be transparent to view the test results. This will also allow existing lids to have tube 601 retrofitted.

This arrangement provides the additional advantage of limiting the testing device to 15 two separate components only. This again reduces the labour involved in assembling the testing apparatus, and also reduces costs associated with producing many different components.

It will be appreciated that the apparatus 100, kit 500 and alternative embodiment 600 of the current invention provide a number of advantages.

The retaining device maintains the test tube in an optimum viewing position near the inside wall of the container. Currently when a durham tube is inserted freely within a container the tube must be moved about in order to view whether a test has a positive result. In cases where the medium has become more opaque during testing this is often difficult, and excessive shaking in order to clearly view the tube 25 inside the container can potentially affect the accuracy of the test. 13 Received by IPONZ 9 May 2011 The apparatus and container are preferably made of inexpensive, recyclable polycarbonate plastic. This material is not only a suitable material for performing accurate testing, but decreases the risks and costs associated with using traditional glass durham tubes and/or vials. Additionally, the present apparatus and 5 kit are able to be provided as a disposable, single use product. This will result in a large amount of time saved that is currently spent in washing and resterilising testing apparatus after each use. Using a disposable testing kit will reduce the risk of cross contamination between test samples, and therefore the accuracy of the tests being performed is likely to improve.

The apparatus of the current invention is also able to be sold as an individual disposable unit that may be inserted into existing containers, providing a lower cost, disposable option for those not wishing to use the full kit.

Alternatively, the kit including both the container and apparatus can be provided as a single use, testing kit. This may be sold as either an empty container and 15 apparatus, or the container may be pre-filled with sterilised medium and provided to the customer in a ready-to-use format which can then be disposed of after use. This use is particularly suited to the alternative embodiment of the invention where the tube and lid are formed as a single apparatus.

Aspects of the present invention have been described by way of example only and 20 it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof. 14

Claims (17)

Received by IPONZ 9 May 2011 What I claim is:

1. A microbiological testing apparatus adapted for attachment to a container, the apparatus including; • a test tube; and • a retention device attached to the test tube; wherein the retention device is adapted to fixedly retain the test tube in an inverted position within the container by means of a friction fit against at least a part of the container.

2. The apparatus of claim 1 wherein the test tube and retention device are integrally formed.

3. The apparatus of claim 1, wherein the test tube is releasably connected to the retention device.

4. The apparatus of any one of claims 1 to 3, wherein the retention device is fixedly retained within the container by biasing against a side wall or walls of the container.

5. The apparatus of any one of claims 1 to 4, wherein the retention device substantially corresponds to the shape of at least a part of the container wall or walls.

6. The apparatus of any one of claims 1 to 5, wherein the retention device is substantially the same height as the container wall or walls.

7. The apparatus of any one of claims 1 to 5, wherein the height of the retention device is substantially less than that of the container wall.

8. The apparatus of any one of claims 1 to 7, wherein the apparatus is made 15 Received by IPONZ 9 May 2011 from transparent polycarbonate plastic.

9. The apparatus of claim 8, wherein the polycarbonate plastic is high clarity, non auto-fluorescing polycarbonate plastic.

10. The apparatus of any one of claims 1 to 3, wherein the retention device is in the form of a lid.

11. A kit for microbiological testing, the kit including; • a container; and • an apparatus as claimed in any one of claims 1 to 10.

12. A method of manufacturing the apparatus as claimed in any one of claims 4 to 10 when dependent on claim 2, the method including the steps of; • preparing a die in the shape of the apparatus; • forming the apparatus from the die using a moulding process.

13. A method of manufacturing the apparatus as claimed in any one of claims 3 to 10 when dependent on claim 1, the method including the steps of; • preparing a first die in the shape of the test tube; • preparing a second die in the shape of the retention device; and • forming the test tube and retention device from the first and second dies using a moulding process.

14. The method of claim 12 or claim 13 where the moulding process used in injection moulding or blow moulding.

15. The method of claim 12 or 13 wherein the moulding process used is multi- 16 Received by IPONZ 9 May 2011 cavity injection moulding.

16. The apparatus substantially as described herein with respect to Figures 1 -9.

17. The method substantially as described herein with respect to Figures 1-9. Peter Bailey by his Attorneys James & Wells Intellectual Property 17