JPH04228063A - Tool for detecting gas production of microorganism and testing kit having the same tool - Google Patents

Abstract

PURPOSE:To provide a tool for detecting the gas production of microorganisms suitable as a disposable and a microbial testing kit using the aforementioned tool. CONSTITUTION:The aforementioned tool is obtained by providing a diaphragm 2 dividing the interior of a culture vessel 1 and forming at least one gas storage chamber 4 under the liquid level of a liquid culture medium contained in the culture vessel 1 and a communicating means (2a) of dimensions having a shape so as to enable free passage of microorganisms which are objects of testing in at least part of the aforementioned diaphragm and collecting bubbles of gases produced by the microorganisms in either of the compartments. The collected bubbles can be observed in a region near the inner wall of the culture vessel.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an instrument for detecting gas production from microorganisms and a test kit having the instrument.

0002

[Prior art] Test items in food microbial testing include
There is an E. coli and coliform test. coliform bacteria (coliform bacteria)
orm bacteria) is an aerobic or facultative anaerobic non-spore bacillus, and is a gram-negative bacterium that decomposes lactose and produces carbon dioxide gas. Taking advantage of this property, coliform bacteria have conventionally been detected using Durham fermentation tubes. In addition, Shigella and Salmonella typhi produce acid by decomposing glucose, but are characterized by not producing gas, and non-gas production is an essential test item for their identification.

[0003] Durham fermentation tubes are small tubes with one end open, into which a test sample is mixed, submerged in a liquid medium after removing internal gas, and cultured for a certain period of time. If gas-producing bacteria are present in the sample, the gas will be trapped in the Durham fermentation tube as bubbles (in extreme cases, the Durham fermentation tube will float), and gas production will occur due to the generation of bubbles or the floating of the Durham fermentation tube. You can know the presence of bacteria.

[0004] Thus, in food and water quality testing, Durham fermentation tubes are used to detect coliform bacteria.

[0005]

[Problems to be Solved by the Invention] However, the work of dispensing the culture medium into the medium test tubes (test tubes containing the culture medium and gas collection test tubes) of the Durham fermentation tube, (Gas collection test tube housed with the side facing down)
The preparatory process, such as submerging test tubes into medium-sized test tubes, and the cleaning of test tubes (especially small test tubes) after the test, place a heavy burden on workers. It is necessary to keep the Durham fermentation tube with its opening facing downwards even during cultivation. Since food processors routinely inspect each item of product they handle, it has been desired to simplify the inspection method and develop a simple inspection means. Furthermore, there are types of coliform bacteria that produce very little gas, and if there are substances that inhibit the growth of microorganisms (e.g. food additives, fats, etc.), they may slow down the growth of microorganisms and reduce gas production. In some cases, especially when the liquid medium is colored with a dye or when the liquid medium is cloudy due to the growth of microorganisms, small air bubbles trapped in the Durham fermentation tube can be visually checked. In some cases, it was not easy to detect.

[0006] In addition, the instruments used in these tests are cleaned and sterilized before and after use, but these operations occupy a large portion of the time required for the tests, and during these operations, the instruments are cleaned and sterilized. Damage may also occur. Accordingly, it would be desirable to provide a gas detection instrument that is suitable for disposable use.

[0007] In order to solve the above-mentioned drawbacks, the Durham fermentation tube is made of a material whose relative specific gravity to the liquid medium is slightly greater than 1, and whose apparent specific gravity is slightly less than 1, and which has a relative specific gravity to the liquid medium and at least a test. Gas detection bodies made of porous materials having voids that allow the entry of target microorganisms have been proposed (for example, Japanese Patent Application No. 2-193237 filed on July 20, 1990 by the applicant).
If the amount of gas produced by microorganisms is small, the gas detector will not float, and therefore cannot detect gas production.

[0008] Accordingly, one object of the present invention is to provide a gas detection instrument that can easily and reliably detect even trace amounts of produced gas.

Another object of the present invention is to provide a microorganism gas production detection device that is easy to manufacture.A further object of the present invention is to provide a microorganism gas production detection device that is easy to manufacture. An object of the present invention is to provide a gas detection instrument.

A further object of the present invention is to aseptically enclose and seal a liquid medium, which is suitable for application to a disposable culture medium enclosure for use in specific microbial tests that are carried out repeatedly on a daily basis. An object of the present invention is to provide a gas detection device for microorganisms.

A further object of the present invention is to aseptically encapsulate a liquid medium in a culture container and apply it to a sealed culture medium enclosure, particularly to sterilely encapsulate a liquid medium and a gas detection device in a culture container. After the user inoculates the test sample into the medium, the user inoculates the test sample into the medium, and then cultivates it in a culture facility to produce a disposable product suitable for determining the presence or absence of gas-producing bacteria (generally coliform bacteria). An object of the present invention is to provide a gas detection instrument suitable for a test kit. The present inventors have conducted intensive research to solve these problems and have arrived at the present invention.

0012

[Means for Solving the Problems] In the microorganism gas production detection device according to the present invention, at least one gas accumulation chamber is formed by partitioning the inside of the culture container below the surface of the liquid medium contained in the culture container. A partition wall is provided, and at least a portion of the partition wall is provided with a communication means having a size and shape that allows the microorganisms to be tested to freely pass through, and gas bubbles produced by the microorganisms are collected in one compartment, and the gas bubbles produced by the microorganisms are collected in one compartment. Air bubbles can be observed in a region close to the inner wall of the culture container.

[0013] There are various embodiments for providing at least a portion of the partition wall with a free passage of the microorganisms to be tested and with the possibility of trapping gas bubbles produced by the microorganisms in one compartment. be.

One measure is to provide at least a portion of the partition wall with a communication means having a size and shape that allows the microorganisms to be tested to pass through freely and does not allow air bubbles to pass under the liquid surface. More specifically, the entire partition wall is formed of a material having a plurality of pores of a size and shape that allow the microorganisms to be tested to pass through freely, but do not allow air bubbles to pass through below the liquid surface. A typical example of such a material is a so-called porous material, but the material is not limited thereto.

[0015] Another solution is to make the partition walls of an airtight material that does not allow the passage of liquids or gases. However, in this case, it is necessary to install the gas detection device in the culture container after inoculating the liquid medium with the test sample. This not only complicates the work but also slows down the growth of aerobic or facultative anaerobic bacteria such as E. coli.

[0016] Therefore, when the partition wall is formed of an airtight material that does not allow the passage of liquid or gas, it is possible to provide a communication means having an opening size and shape large enough to allow microorganisms and air bubbles to pass through under the liquid surface. . In this case, it is necessary to prevent the gas to be collected from escaping through the cutout or opening.

One solution for this purpose is to form the cutout or opening in such a way that it can be placed at a lower level than the gas accumulation chamber during culturing. or,
The cutout or opening is covered with a material having a plurality of pores of a size and shape that allows the microorganisms to be tested as described above to freely pass therethrough, but does not allow air bubbles to pass under the liquid surface.

[0018] In addition, when the partition wall is formed of an airtight material that does not allow the passage of liquid or gas, the above-mentioned communication means can be used to allow the microorganisms to be tested to freely pass through, and to substantially eliminate air bubbles below the liquid surface. It is formed as at least one cutout or opening with a size and shape that does not allow passage. Generally, it is rather difficult to form fine bubbles in liquid, and gas bubbles are of a certain size.
The authors focused on the fact that such micropores that do not allow air bubbles to pass through can freely allow microorganisms to pass through. In fact, it is possible to form a cutout or opening with such a size and shape depending on the material of the partition wall, the properties of the liquid medium, and the relationship between surface tension.

Further, in a preferred embodiment of the present invention, supporting means is provided for supporting the partition wall at a desired position in the culture container in a desired posture.

[0020] Also, it is desirable that the gas detection instrument, like the related culture vessel, be made of a material that can be sterilized and is inexpensive, and that it be disposable. It is also necessary that the material of the gas detection device has no biological activity that inhibits the growth of microorganisms that are the object of detection. Furthermore, when the culture solution contains pigments or coloring agents (for example, pH indicators), it is also necessary to select materials that are difficult to absorb them. The size and shape of the partition wall vary depending on the size and shape of the culture container used and in which part of the wall of the culture container the compartment chamber for accumulating gas (hereinafter referred to as a gas accumulation chamber) is provided.

In a typical embodiment of the present invention, a culture vessel having a cylindrical side wall is used, and a gas accumulation chamber is formed by bringing the partition wall of a gas detection device into contact with the inner surface of the side wall without a gap. . In such a case, the partition wall can be shaped like a disk or an elliptical plate that contacts the inner surface of the cylindrical side wall without a gap.

For example, the partition wall can be sloped to provide a cutout or opening in an area located below the level of the lower surface of the partition wall. It is desirable that the ratio of the opening area of the cutout or opening to the horizontal cross-sectional area of the gas accumulation chamber be as small as possible to avoid dissipation of gas bubbles produced by microorganisms as much as possible. It is also desirable to provide a so-called "baffle plate" below the cutout or opening in order to avoid gas bubbles from entering the cutout or opening. In this case, the area ratio mentioned above can be ignored.

Alternatively, a surrounding wall or a surrounding pipe may be provided around the notch or opening to hang down from the lower surface of the partition wall. In this case, it is desirable that the ratio of the opening area formed by the surrounding wall provided around the notch and the container wall of the culture container to the horizontal cross-sectional area of the gas accumulation chamber be as small as possible; Even when the tube opens downward, it is desirable that the ratio of the opening area to the horizontal cross-sectional area of the gas accumulation chamber be as small as possible. Thereby, it is possible to reduce the dissipation of gas bubbles produced by microorganisms from the opening. In addition, these openings should be covered with a material (filter material) that has microscopic voids in a size and shape that allows the microorganisms to be tested to pass through freely and that does not allow gas bubbles produced by the microorganisms to pass through, or such material should be covered with a material with no gaps. You can also pack it in without it.

[0024] It is also desirable to curve the tip of the cylindrical surrounding tube so that the opening faces horizontally or upward, or to place a "baffle plate" below it. In these cases, the above-mentioned area ratio can be ignored. However, it is necessary that during cultivation the opening can be positioned at a level below the gas accumulation chamber. The separation dimension depends on the volume of the gas bubbles collected in the gas collection chamber.

[0025] It is also desirable to provide support means for supporting the above-mentioned partition wall at a desired position in the culture container in a desired posture. Such support means can be formed in a variety of ways, some of which are described in the examples below.

The microorganism gas production detection device according to the present invention can be supplied in sizes and shapes compatible with commercially available culture vessels of various shapes and sizes.

[0027] Furthermore, the microorganism gas production detection device according to the present invention can be supplied as a test kit in which a desired liquid medium is aseptically sealed in a culture container and incorporated into a hermetically sealed medium enclosure. In this case, air bubbles may pass from one compartment to the other between at least two compartments separated by the partition of the gas detection device during transportation of the test kit, both before and after inoculation of the test sample. is not desirable. If air bubbles form on the underside of the septum before the test sample, it is necessary to expel the bubbles above the septum before inoculating the test sample. This is because if the gas that has been removed dissipates to the upper side of the partition wall, or if the gas existing above the partition wall enters the lower side of the partition wall during transportation, erroneous test results will be produced. However, it is also desirable to be able to easily expel air bubbles, if any, within the gas accumulation chamber prior to inoculation with the test sample. It is desirable to satisfy these mutually contradictory requirements.

In the most preferred embodiment of the invention,
The gas detection device is made of an elastic material, and the gas detection device includes a cylindrical side wall and an upper portion formed by folding back into the cylindrical side wall from the lower end of the cylindrical side wall. and a truncated cone-shaped partition wall tapering toward the cylindrical side wall, the communication means being formed on the top surface of the truncated cone, and the partition wall being inverted to a tapered shape toward the bottom of the cylindrical side wall. is now possible.

In a preferred embodiment of the invention, a sediment reservoir is provided around the periphery of the communication means. This can prevent the opening from being blocked by particles contained in the sample. The composition of the liquid medium includes appropriate components (e.g., lactose, glucose, etc.) depending on the type of microorganism to be detected, and an appropriate indicator (e.g., pH indicator).
Mix it with. This allows specific microorganisms (e.g., Escherichia coli microorganisms), or the presence or absence of microorganisms with certain bacteriological properties from an unspecified microbial group, or specific microorganisms can be identified. Indicators other than the above-mentioned pH indicators include those that react with a specific or characteristic product produced by a limited group of microorganisms or a specific microorganism to the outside of the microbial cell, resulting in a visually discernible change, such as a change in color. , turbidity, precipitation,
If an indicator that produces fluorescence exists, it would be possible to use such an indicator in place of a pH indicator, thereby targeting a limited range of microbial groups in a specific type of specimen, not just food. Can be applied to microbial testing. The culture container described above can be made of resin and made disposable.

[0030] The microorganism gas production detection device according to the present invention traps gas produced by microorganisms in a gas accumulation chamber surrounded by a partition wall and the inner surface of the container wall of the culture container by the partition wall portion, and Since it accumulates close to the inner surface and prevents it from dissipating, even minute bubbles can be observed easily and efficiently.

[0031] By forming the culture container and the microorganism gas production detection device from an appropriate synthetic resin material, they can be made disposable. In this case, by providing the gas detection device with support means, the gas production detection device can be made disposable. The stability of the posture of the gas detection device and the airtightness of its partition wall portion can be improved, and the culture container can be further reinforced, and the culture container can be formed from a relatively thin material. Furthermore, by extending the support means below the opening, the opening can be separated from the bottom wall of the culture container.

[0032] By aseptically enclosing and sealing the above-mentioned gas detection device and a liquid medium of a predetermined composition in a culture container and supplying the same as a test kit, microbial tests such as routine food tests can be easily performed. Moreover, it becomes possible to carry out the inspection reliably and efficiently, and it becomes possible to save labor in the inspection.

The method of the present invention, the gas detector used in the method, and the microbial test kit have been outlined above, but in order to better understand the present invention, the present invention will be explained in more detail through Examples.

[0034]

[Embodiment] Fig. 1 shows a culture vessel (test tube) 1 and a microorganism produced gas detection instrument 2 according to the simplest embodiment of the present invention.
and FIG. 3 is an elevational sectional view showing a state in which a liquid medium 3 is placed.

In this example, the culture vessel 1 is shown as a conventional test tube with a circular cross-sectional shape. The gas detection device 2 is shown as a simple disk-shaped partition 2. The diameter of the disk-shaped partition wall is equal to or slightly larger than the inner diameter of the culture container. In this way, the partition wall 2 has its circumferential portion in contact with the side wall of the culture container 1 without any gap, and the liquid medium 3
The gas accumulation chamber 4 is formed below the partition wall 2.

In this embodiment, the partition wall 2 is made of, for example, a filter material and has a plurality of micropores with a size and shape that allows at least the microorganisms to be tested to freely pass through, but does not allow the passage of gas bubbles produced by the microorganisms. The micropores function as communication means through which at least the microorganisms to be tested can freely pass through the gas accumulation chamber 4, and which do not allow gas bubbles produced by the microorganisms to pass through. Filter materials having such pore sizes are commercially available and readily available.

[0037] In use, a liquid medium 3 is placed in the culture container 1.
is aseptically injected, and the partition wall 2 is inserted below the liquid surface of the liquid medium 3 with its plate surface oriented substantially vertically, and then the partition wall 2 is pushed down to the state shown in FIG. 1. Thus, a gas accumulation chamber 4 is formed below the partition wall 2. Thereafter, a test sample (not shown) is inoculated into the liquid medium 3 above the partition wall 2.

[0038] The thus prepared culture container is cultured in an incubator for a predetermined period of time. If the microorganisms in the test sample produce gas, the gas bubbles 5 are restrained by the disc-shaped partition wall 2, and by tilting the culture container 1, the bubbles float along the disc-shaped partition wall 2. and gather in one place close to the container wall of the culture container 1. In this way, trace amounts of gas can be easily and reliably detected.

In the embodiment shown in FIG. 1, the partition wall 2 is an elliptical plate-like member, and can be arranged at an angle below the liquid level of the culture container 1. In this case, the gas bubbles produced by the microorganisms can be removed without tilting the culture vessel.
They can be accumulated close to the side wall of the culture container 1.

FIG. 2(a) is an elevational cross-sectional view showing a state in which a microorganism produced gas detection device 2 and a liquid medium 3 according to another embodiment of the present invention are placed in a culture container 1. b)
is a perspective view of the gas detection instrument 2 of FIG. 2(a).

In this example as well, the culture vessel 1 is shown as a conventional test tube with a circular cross section. The gas detection instrument 2 is shown as a partition wall 2 made of an elliptical plate-shaped body, and a notch 2a is formed at one end of its major axis.

The major axis and minor axis of the elliptical partition wall are the culture vessel 1.
It is equal to or slightly larger than the major axis and minor axis of the cross-sectional shape (ellipse) of the inner surface of the side wall when the culture container 1 is cut along a plane inclined with respect to the central axis of the culture vessel 1.

[0043] Thus, the partition wall 2 can be attached to the culture container 1 in an inclined manner in the manner shown in the figure. In this embodiment, the partition wall 2 may be made of a plate-shaped material such as polyethylene resin, polypropylene resin, or the like.

[0044] In use, a liquid medium 3 is placed in the culture container 1.
is aseptically injected, and the partition wall 2 is inserted below the liquid surface of the liquid medium 3 with the plate surface inclined with respect to the horizontal plane, so that the oval side surface of the partition wall is brought into close contact with the inner wall surface of the culture container 1. At this time, the notch 2a is positioned at the lowest level of the inclined partition wall 2. Thus, a gas accumulation chamber 4 is formed below the partition wall 2.

A test sample (not shown) is injected into the liquid medium 3 of the culture container 1 above the partition wall 2, and the culture container thus prepared is incubated in an incubator for a predetermined period of time. If microorganisms in the test sample produce gas, the gas bubbles 5 will float along the disc-shaped partition wall 2 and gather in one place near the wall of the culture container 1, producing a trace amount of gas. can be detected easily and reliably. A portion of the gas bubbles 5 may dissipate from the communication means 2a, but by making the area of the communication means 2a smaller than the cross-sectional area of the culture container 1, the amount of dissipation can be minimized. . If necessary, it is also possible to provide a so-called "baffle plate" (not shown) below the communication means 2a to prevent gas bubbles 5 from escaping from the communication means 2a. In this example, it is also possible to culture by making the partition wall into a perfect circle and tilting the culture container 1 so that the part provided with the notch 2a is at the lowest level.

FIG. 3(a) is an elevational cross-sectional view showing a state in which a microorganism-produced gas detection instrument 2 and a liquid medium 3 according to still another embodiment of the present invention are placed in a culture container 1. (
b) is a perspective view of the gas detection instrument 2 of FIG. 3(a).

In this embodiment as well, the culture vessel 1 is shown as a normal test tube with a circular cross section. The gas detection device 2 is a plate-like member that appears elliptical when viewed from above, and has a structure in which a stepped portion 2b is provided perpendicular to its major axis, and a communication means 2a or an opening is provided on the rising surface of the stepped portion 2b. It is shown as. The major axis of the elliptical outer shape of the gas detection device 2 is larger than the major axis of the ellipse formed by the inner surface of the side wall of the culture container 1 when the culture container 1 is cut along the plane with the inclination angle shown in FIG. 3(a). Slightly long. The short axis is equal to or slightly larger than the inner diameter of the side wall of the culture container 1. Thus,
When the gas detection device 2 is inserted with its major axis slightly compressed by tilting it as shown in FIG. Ru. That is, the partition wall portion positioned below functions as a "bending plate" with respect to the communication means 2a.

FIG. 4 is an elevational sectional view of a state in which the liquid medium 3 and the gas detection instrument 2 are placed in each culture container in the plurality of culture container assembly 11.

In this embodiment, the culture vessel 1 is shown as having an inverted truncated cone shape. Gas detection instrument 2 generally has a funnel-like shape. To be more specific, the gas detection device 2 includes a side wall portion 2c of an inverted truncated cone, and a communication means 2.
a disc-shaped or ring-shaped bottom wall portion 2d,
The communication means 2a is surrounded by a surrounding pipe 2e that hangs downward from the lower surface of the bottom wall. The opening area of the communication means 2a has a size and shape sufficient to allow gas bubbles produced by microorganisms to pass therethrough. The communication means 2a having such a size and shape allows the microorganisms to be tested to freely pass therethrough. The side wall portion 2c of the inverted truncated cone is
It has an inverted truncated conical outer shape that contacts the inner surface of the intermediate portion of the side wall of the culture container 1 without a gap, and functions as a support means for supporting the gas detection instrument 2 at a desired position and in a desired posture. In use, after the gas detection device 2 is attached to each culture container 1 in the state shown in FIG. 4, a liquid medium is poured into the culture container. The injected liquid medium also flows into the gas accumulation chamber 4 through the opening. However, some amount of air is left behind in the gas accumulation chamber 4. When the culture container 1 prepared in this way is sterilized with high pressure steam in an autoclave or the like (for example, at 121° C. for 15 minutes), the liquid medium 3 in the gas accumulation chamber 4 generates water vapor, and the liquid medium 3 in the gas accumulation chamber 4
The water vapor is discharged from the air via the communication means 2a, and the water vapor is discharged together with the air. Thereafter, when the culture container 1 is cooled, the inside of the gas accumulation chamber 4 becomes negative pressure, the liquid medium 3 flows into the gas accumulation chamber 4 through the communication means 2a, and air is substantially expelled from the gas accumulation chamber 4. Thereafter, a test sample is inoculated into the liquid medium 3 above the partition wall 2. Microorganisms can freely move into the gas accumulation region 4 through the communication means 2a.

The culture container 1 thus prepared is cultured in an incubator for a predetermined period of time. If the microorganisms in the test sample produce gas, the gas bubbles 5 will be restrained by the disc-shaped bottom wall 2d, and by tilting the culture container 1, the gas bubbles 5 will move along the lower surface of the bottom wall. It floats to the surface and gathers in one place close to the container wall of the culture container 1. In this way, trace amounts of gas can be easily and reliably detected. A portion of the gas bubbles 5 dissipates from the communication means 2a, but by making the area of the communication means 2a considerably smaller than the cross-sectional area of the culture container 1, the amount of dissipation does not become so large. If necessary,
It is also possible to provide a so-called "baffle plate" (not shown) below the communication means 2a to prevent gas bubbles 5 from escaping from the communication means 2a. Alternatively, the communication means 2a is covered with a material (filter material) having micropores that allow the microorganisms to be tested to pass through freely but do not allow air bubbles to pass through.
Alternatively, it may be filled with such materials. In this embodiment, the bottom wall 2d in the shape of an inverted truncated cone has a function as a partition wall, and forms the gas accumulation chamber 4 below it. Also,
The side wall 2c in the shape of an inverted truncated cone is the bottom wall 2 that functions as a partition wall.
It also has the function of increasing the confidentiality of d.

FIG. 5 is an elevational sectional view showing a modification of the gas detection instrument 2 shown in FIG.

In this embodiment, the inverted truncated conical side wall 2c extends from the lower surface of the bottom wall 2d to below the surrounding tube 2e. The side wall 2c in this embodiment is capable of reinforcing the side wall of the culture container 1 by contacting it over the entire height of the side wall of the culture container 1. This is suitable for reinforcing the culture container 1 since the culture container assembly 11 is molded from a thin sheet material such as polyethylene resin when the culture container assembly 11 is disposable. This is also effective for reliably accumulating gas bubbles in the gas accumulation chamber 4. Otherwise,
When the side wall of the culture container 1 is lifted with a finger, the side wall of the culture container 1 may be deformed, and gas bubbles 5 may dissipate from between the side wall of the culture container 1 and the side wall 2c of the gas detection device 2. It is from. Furthermore, in this embodiment, the surrounding pipe 2
(e) A filter 6 formed of a material having micropores with a size and shape that allows the microorganisms to be tested to freely pass through and that does not allow the gas bubbles 5 produced by the microorganisms to pass through.
are packed without any gaps. As a result, the liquid medium 3 and the gas detection device 2 are aseptically enclosed in a culture container, and the gas detection device is more suitable as a gas detection device applied to a culture medium sealed body that is sealed and supplied. This filter 6 prevents air from entering the gas accumulation chamber 4 divided by the gas detection device 2 during transportation of the culture medium sealed body,
This is also because bubbles can be prevented from escaping from the gas accumulation chamber 4. As the filter 6, various porous materials, fiber lumps (for example, cotton-like), felt-like fiber aggregates, non-woven fiber aggregates, fiber bundles, porous membrane materials, etc. can be used. Such a medium sealed body can be stored for a long period of time. Therefore, for example, by supplying such a sealed culture medium to a food processing company, and after inoculating the test sample into the culture medium, the company can outsource the cultivation and determination of the presence or absence of microorganisms to a testing facility, thereby relieving the burden of microbial testing. .

In the embodiment of FIGS. 4 and 5, the surrounding tube 2
When the diameter of e is increased upward, when the test sample is injected below the septum, the pipette (
This is useful for guiding the tip of a tube (not shown). However, sample injection is generally performed above the partition wall.

FIG. 6 is a sectional view similar to FIG. 5, showing a modification of the embodiment of FIG. In this embodiment, a ring-shaped flange 2f is provided at the upper end of the side wall 2c, and a recess 1f for receiving the flange 2f is provided above the culture container 1.
is formed. Thus, by fitting them together and adhering and sealing them as necessary, the gas detection instrument 2 is stably supported in the culture container 1. Features other than those described above are completely similar to those in FIG. 5, and like parts are designated with like reference numerals.

FIGS. 7 and 8 are views similar to FIGS. 5 and 6 showing a further modification of the embodiment shown in FIG. In this embodiment, the detection instrument 2 includes a cylindrical side wall 2c, a bottom wall 2d,
It has a plurality of legs 2g extending downward from the lower surface of the bottom wall 2d. The legs 2d are shown in this example as having three legs 2d arranged along a vertical plane including lines extending radially from the center of the bottom wall, which This is just an example of a convenient arrangement and orientation.
The arrangement and orientation of the leg portions 2d are not limited thereto. The outer surface of the cylindrical side wall 2c has an outer shape that comes into close contact with the side wall of the culture container 1 when the lower end of the leg 2g comes into contact with the bottom wall of the culture container 1, and the bottom wall 2d serves as a communication means. It has at least one opening 2a, and the lower surface of the bottom wall 2d slopes upward from the opening 2a toward the side wall to form a partition. In this embodiment, the circumference of the small hole 2a is shown as having an upwardly projecting surrounding wall 2e, contrary to the embodiments shown in FIGS. Although the small hole 2a is depicted in the center of the bottom wall 2d, it does not necessarily have to be in the center.

Furthermore, in this embodiment, three outwardly protruding protrusions 2h are provided that are spaced apart in the radial direction from the outer peripheral edge of the upper end of the side wall 2c. The purpose of these protrusions 2h is to lock the protrusions 1a formed in a ring shape on the inner wall surface of the culture container 1, and to separate and lock the lower end of the leg 2g from the bottom wall of the culture container 1. have When the detection device 2 is pressed from above, the detection device 2 and/or the culture container 1 are deformed, and the lower ends of the legs 2g can be easily brought into contact with the bottom wall of the culture container 1. The embodiment having this protrusion 2h is excellent in the following points. That is, when the gas detection device 2 of this embodiment is supplied to a consumer as a product that is sterilized and sealed together with the liquid medium 3 in the culture container 1, there is no possibility that air will escape during transportation, except for the examples shown in FIGS. 1, 5, and 6. Partition wall (bottom wall 2d of detection instrument
), but in this embodiment, if the protrusion 2h on the peripheral edge of the detection device 2 is locked in the above-mentioned locking position, the outside of the side wall 2c of the detection device 2 A gap is created between the side surface and the inner surface of the side wall of the culture container 1, and when the gas detection device 2 is pressed downward, the liquid medium 3 is pushed upward through the opening 2a and the gap, and at this time, in case air escapes If it remains below the bottom wall 2d (partition wall),
It is discharged along with the liquid flow. Further, the liquid flow from the opening 2a has the effect of eliminating particles that may be included in the test sample even if the opening is blocked. Thus, microorganisms in the test sample can easily enter the lower part of the partition wall through the opening 2a. Further, a recess formed at the periphery of the surrounding wall 2e projecting upward functions as a precipitate reservoir for particles in the test sample, thus preventing the opening 2a from being blocked. In the illustrated embodiment, a truncated conical space is formed below the surrounding wall 2e, and when gas produced by microorganisms is trapped in this space, it is difficult to detect it. (Bottom wall) Area of 2d and surrounding wall 2e
If the ratio between the area of the base of the truncated cone and the area of the base of the truncated cone is sufficiently small, there will be no problem with the inspection. Further, if necessary, the inner surface of the truncated cone of the surrounding wall can be made cylindrical, or the shape of the surrounding wall can be made cylindrical. Further, instead of providing the projection 2h on the detection instrument side, a projection protruding inward may be provided on the inner surface of the side wall of the culture container 1.

FIG. 9 shows a further embodiment of the present invention, and FIG. 9(a) shows the state in which the culture solution 3 and the gas detection device 2 are placed in the culture container 1 with solid lines. and
FIG. 9(b) shows a plan view of the gas detection instrument 2 of FIG. 9(a). The gas detection device 2 of this embodiment is made of an elastic material, such as polypropylene resin, and has no biological activity against microorganisms, and has a cylindrical side wall 2.
c, and a truncated conical partition wall 2 formed by folding back into the cylindrical side wall 2c from the lower end of the cylindrical side wall 2c.
d, and has an opening 2a on the top surface of the truncated cone with a size and shape that allows air bubbles to freely pass under the liquid surface, and the partition wall 2d is as shown by the dotted line in FIG. 9(a). It can be inverted below the cylindrical side wall 2c. (b) in Figure 9
), the opening 2a is shown as a cross-shaped opening, but it is not limited thereto. In use, the gas detection device 2 shown in the figure is placed in the inverted truncated cone-shaped culture container 1.
is pushed in and locked in the state shown by the solid line. At this time, the detection device 2 is submerged below the surface of the culture solution. The bubbles that have entered the lower part of the partition wall 2d are discharged from the opening 2a to the upper part of the partition wall along with the liquid flow. The test sample is partition wall 2d
The truncated cone-shaped partition wall 2d is inverted to the state shown by the dotted line, and culture is performed for a desired time. Gas bubbles produced by the microorganisms are collected on the side wall of the culture container 1 along the inclined surface of the partition wall 2d. A portion of the gas produced by the microorganisms is dissipated through the opening 2a, but as long as the ratio of the area of the opening 2a to the total area of the partition wall 2d is sufficiently small, there is no problem with the inspection. If necessary, it is also possible to provide a baffle plate below the opening 2a to avoid dissipation of the gases produced by the microorganisms.

In addition, when the pores, notches, or openings serving as communication means in each of the above-mentioned embodiments are designed to have a size and shape that allows air bubbles to freely pass through, the ratio of the opening area to the total area of the partition wall should be made as small as possible. , it is necessary to prevent the dissipation of air bubbles, preferably by providing a baffle plate, and if the opening is sized and shaped to allow the microorganisms to be tested to pass through freely and to substantially prevent the passage of air bubbles, The upper limit of the caliber is such that the tip of a sterilized instrument (e.g., pipette) used to open the lid (not shown) that seals the top of the culture container 1 will not fit (e.g., It is desirable that the diameter is 1 mm) or smaller. In addition, the concentration of carbon dioxide gas dissolved in the liquid medium above and below the partition wall tends to become homogenized, and since the dissolved carbon dioxide gas evaporates from the surface of the liquid medium above the partition wall, the pores ( It is desirable that the total opening area) and the area of the notch or opening be as small as possible, and
It is desirable that the cross-sectional area of the culture container at the sample medium injection level be as small as possible, and furthermore, it is desirable to take care to reduce the surface area of the liquid medium as the opening area of the communication means increases.

In each of the above-mentioned embodiments, if the size of the pore, cutout, or opening serving as the communication means is small, there may be some difference in the number of microorganisms that can enter the lower part of the partition wall. The proliferation of these animals increases the number of individuals in an incongruous manner, so it does not cause errors in test results.

Although some embodiments and variations thereof of the present invention have been described in detail above, the present invention is not limited to the above-mentioned embodiments, and various modifications may be made within the scope of the technical idea of the present invention. Deformation is possible. For example, a test kit can be provided in which a liquid medium and the gas detection instrument of the present invention are aseptically sealed in each culture container in an assembly of a plurality of culture containers using a sealing lid.

[0061]

[Effects of the Invention] The effects of the present invention are as follows.

(1) Since gas bubbles produced by microorganisms accumulate close to the wall of the culture container,
Visual observation is easy and the generation of trace amounts of gas can be reliably observed.

(2) Handling and use of the gas detection device is easier than with the Durham fermentation tube.

(3) The gas detection device can be manufactured at low cost and is suitable for disposable use.

(4) Routine microbial testing, especially in the food field, can be performed easily, reliably, and at low cost by aseptically sealing a liquid medium in a culture container and pre-sealing it in a sealed liquid medium enclosure. This makes it possible to save labor in inspection.

[Brief explanation of the drawing]

FIG. 1 is an elevational cross-sectional view of a gas detection device and a liquid culture medium placed in a culture container according to an embodiment of the present invention.

FIG. 2 shows another embodiment of the invention, FIG.
1 is a vertical cross-sectional view of a state in which a gas detection device and a liquid culture medium according to the example are placed in a culture container. Figure 2b is Figure 2a
FIG. 2 is a perspective view of a gas detection instrument.

3 shows still another embodiment of the present invention, FIG. 3a is an elevational cross-sectional view of the gas detection device and liquid medium according to this embodiment placed in a culture container, and FIG. 3b is the same as that of FIG. 3a. It is a perspective view of a gas detection instrument.

FIG. 4 is an elevational cross-sectional view of a gas detection device and a liquid medium placed in a culture container according to another embodiment of the present invention.

5 is an elevational sectional view showing a modification of the gas detection instrument of FIG. 4. FIG.

6 is a sectional view similar to FIG. 5 showing a modification of the embodiment of FIG. 5;

7 is a diagram similar to FIG. 5 showing a further modification of the embodiment of FIG. 4;

FIG. 8 is a diagram corresponding to FIG. 6 of the embodiment of FIG. 7;

FIG. 9 shows a further embodiment of the present invention, in which (a) shows a culture medium 3 and a gas detection device 2 in a culture container 1;
The solid line shows the state in which the gas detection device is arranged, and (b) shows a plan view of the gas detection device of (a).

[Explanation of symbols]

1: Culture container, 1f: recess, 2: Gas detection equipment (bulkhead), 2a: opening, 2b: step part, 2c: side wall of gas detection device, 2d: bottom wall of gas detection device, 2e: Surrounding pipe of gas detection device, 2f: flange, 2g: legs, 2h: protrusion, 3: Liquid medium, 4: Gas accumulation chamber, 5: Gas bubbles, 6: Filter.

Claims (8)

[Claims] Claim 1: Below the liquid surface of a liquid medium contained in a culture container, a partition wall is provided that partitions the inside of the culture container to form at least one gas accumulation chamber, and a microorganism to be tested is free in at least a portion of the partition wall. a communication means sized and shaped to allow gas bubbles produced by the microorganisms to be collected in one of the compartments, such that the collected air bubbles can be observed in an area proximate to the inner wall of the culture vessel. A microbial gas production detection device characterized by: 2. The gas production detection device according to claim 1, wherein at least a portion of the partition wall has a size and shape that allows at least microorganisms to be tested to freely pass through, and substantially prevents air bubbles from passing below the liquid surface. 1. An instrument for detecting gas production from microorganisms, characterized in that the device is made of a porous material having a plurality of pores, and the communication means is constituted by the pores. 3. The gas production detection device according to claim 1, wherein the partition wall is made of a material that does not allow liquid or gas to pass through, and the communication means has a size that is smaller than the size that allows air bubbles to pass through below the liquid surface. 1. A gas production detection device for microorganisms, characterized in that the cutout or opening has a large opening size, and the cutout or opening can be placed at a lower level than the gas accumulation chamber during culturing. 4. The gas production detection device according to claim 1, wherein the partition wall is formed of a material that does not allow passage of liquid or gas, the communication means allows at least microorganisms to be tested to freely pass through, and A microbial gas production detection device characterized by having at least one cutout or opening of a size and shape that substantially prevents air bubbles from passing under the liquid surface. 5. The microorganism gas production detection device according to any one of claims 1 to 4, further comprising support means for supporting the partition wall at a desired position in the culture container in a desired posture. A microbial gas production detection device characterized by: 6. The microorganism gas production detection device according to claim 3 or 4, wherein the detection device is made of an elastic material, and has a cylindrical side wall and a cylindrical side wall. a truncated conical partition wall tapering upwardly and formed by folding back into the cylindrical side wall from the lower end, the communication means being formed on the top surface of the truncated cone; A gas production detection device for microorganisms, characterized in that the partition wall can be inverted into a tapered shape toward the bottom of the cylindrical side wall. 7. The microorganism gas production detection device according to claim 3 or 6, characterized in that a sediment reservoir is provided in the periphery of the communication means. Gas production detection instrument. 8. A test kit in which the following is aseptically sealed in one culture container or in each culture container in a concatenation of a plurality of culture containers and sealed with a sealing lid. (a) a liquid medium, and (b) a partition wall that partitions the inside of the culture container to form at least one gas accumulation chamber below the liquid surface of the liquid medium contained in the culture container, and at least a portion of the partition wall is inspected. A communication means with a size and shape that allows the target microorganisms to freely pass through is provided, gas bubbles produced by the microorganisms are collected in one compartment, and the collected air bubbles are observed in an area close to the inner wall of the culture container. An instrument for detecting gas production from microorganisms.