阅读说明：本技术 微生物测试装置、提供这种装置的方法及其用途 (microbial testing device, method of providing such a device and use thereof ) 是由 弗洛里安·米歇尔 弗雷德里克·富科 克里斯蒂娜·罗藏 于 2018-04-10 设计创作，主要内容包括：本发明涉及一种微生物测试装置(10),用于测试易于含有至少一种微生物的待分析的液体,该微生物测试装置的类型包括：-封闭内部空间(12)；-微生物过滤构件(32),-入口(40),其特征在于,该装置(10)包括与过滤构件(32)接触的营养层(36),并且在用于提供该装置(10)的构造中：-入口(40)的打开/关闭构件(46)处于关闭状态；-封闭内部空间(12)内的绝对气体压力严格小于标准大气压力,使得该装置能够在打开/关闭构件(46)的第一次打开期间通过入口产生抽吸。本发明还涉及提供这种装置的方法和这种装置的用途。(the invention relates to a microbiological test device (10) for testing a liquid to be analyzed susceptible to containing at least one microorganism, of the type comprising: -an enclosed inner space (12); -a microbial filtration member (32), -an inlet (40), characterized in that the device (10) comprises a nutrition layer (36) in contact with the filtration member (32), and in a configuration for providing the device (10): -the opening/closing member (46) of the inlet (40) is in a closed condition; -the absolute gas pressure inside the closed internal space (12) is strictly less than the standard atmospheric pressure, so that the device is able to generate suction through the inlet during the first opening of the opening/closing member (46). The invention also relates to a method of providing such a device and to the use of such a device.)

1. A microbiological test device (10) for testing a liquid to be analyzed susceptible to containing at least one microorganism, said microbiological test device (10) being of the type comprising:

-a closed inner space (12) delimited by a chamber and configured to receive the liquid to be analyzed;

-a microbial filtration member (32) arranged in the closed interior space (12) and separating a first compartment (12a) from a second compartment (12b) of the closed interior space in the closed interior space;

-an inlet (40) for the liquid to be analyzed, which inlet opens into the first compartment (12a) of the closed inner space,

Characterized in that said microbiological detection device (10) comprises, within said closed inner space, a nutrient layer (36), said nutrient layer (36) comprising a component of a microbiological culture medium, said nutrient layer (32) being in contact with said filtering means (32), said inlet (40) of said microbiological test device comprising an opening/closing means (46), and in a configuration for providing said microbiological test device (10) prior to use:

-the opening/closing member (46) of the inlet (40) is in a closed condition for closing in a gastight manner the inlet (40) and the closed inner space (12);

-the absolute gas pressure inside the closed internal space (12), with respect to the temperature of 25 ℃, is strictly less than the standard atmospheric pressure of 1 bar at 25 ℃, so that the device is able to generate suction through the inlet during the first opening of the opening/closing member (46).

2. The microbiological test device according to claim 1 wherein, in a configuration for providing said microbiological test device (10) prior to use, said enclosed interior space (12) is isolated from any external source of suction.

3. the microbiological test device according to any one of the previous claims wherein in a configuration for providing said device (10) prior to use, said microbiological culture medium of said nutritive layer (36) is dehydrated.

4. The microbiological test device according to any one of the previous claims, wherein said microbiological test device (10) comprises a support (48) for said filter member (32) and said nutrient layer (36).

5. The microbiological testing device according to claim 4, wherein said nutrient layer (36) is locally fixed between said filter member (32) and said support (48) for said filter member (32).

6. The microbiological test device according to any one of the claims 4 or 5, wherein said support (48) for said filter member (32) comprises a support partition (50) arranged in said second compartment (12 b).

7. The microbiological test device according to any one of the claims 4 or 5 wherein said support (48) for said filter member (32) comprises a screen (49), said screen (49) extending through a closed inner space between said first compartment (12a) and said second compartment (12 b).

8. The microbiological test device according to any one of the previous claims wherein a water absorbent material is arranged in said second compartment (12 b).

9. Device according to any one of the preceding claims, wherein said opening/closing means (46) of said inlet (40) comprise a valve.

10. The microbiological test device according to any one of the previous claims, wherein said chamber of said microbiological test device comprises at least one body (14) at least partially delimiting said second chamber (12b) and comprises a cover (16) at least partially delimiting said first chamber (12a), said body and said cover being formed by separate parts assembled together to form said microbiological test device.

11. The microbiological test device according to any one of the previous claims wherein said chamber of said microbiological test device includes at least one transparent portion.

12. The microbiological test device according to any one of the previous claims wherein said inlet (40) comprises a distributor (46), said distributor (46) comprising several separate channels for said liquid to be analyzed.

13. Device according to any one of the preceding claims, characterized in that, in the configuration for providing the device (10) before use, the absolute gas pressure inside the closed internal space (12) is such as to enable, during the entry of a predetermined volume of sample to be analyzed, the entry of a predetermined volume of said sample to be analyzed without the exit of fluid from said internal space.

14. Device according to any one of the preceding claims, characterized in that, in the configuration for providing the device (10) before use, the absolute gas pressure inside the closed internal space (12) is strictly less than the standard atmospheric pressure times the ratio of the final free volume in the internal space, after the entry of a predetermined volume of the sample to be analyzed, divided by the total volume of the internal space.

15. Device according to any one of the preceding claims, characterized in that, in the configuration for providing the microbiological test device (10) before use, the absolute gas pressure inside the closed internal space (12) is strictly less than 600 mbar absolute pressure, preferably strictly less than 300 mbar absolute pressure, more preferably strictly less than 200 mbar absolute pressure, with respect to a temperature of 25 ℃.

16. A method for providing a microbiological test device for testing a liquid to be analyzed susceptible to containing at least one microorganism, the method comprising providing a microbiological test device (10), the microbiological test device (10) comprising:

-a chamber arranged for delimiting an enclosed inner space (12), said enclosed inner space (12) being configured to receive said liquid to be analyzed;

-a microbial filtration member (32) arranged to be arranged in the closed interior space and to separate a first compartment (12a) from a second compartment (12b) of the closed interior space in the closed interior space;

-an inlet (40) for the liquid to be analyzed, which inlet opens into the first compartment (12a) of the closed inner space (12),

characterized in that the method comprises providing a nutrient layer (32), the nutrient layer (32) being arranged to be received within the enclosed interior space (12) and comprising a component of a microbiological culture medium, the nutrient layer (36) being in contact with the filter member (32),

And the method comprises, before connecting the microbiological test device (10) to the container of liquid to be analyzed, sequentially and in the following order:

-a pressure reduction step to reduce the absolute gas pressure inside the closed internal space (12) to strictly less than 1 bar with respect to a temperature of 25 ℃;

-a closing step of closing the closed inner space (12) in a gastight manner.

17. The method of claim 16, wherein the depressurizing step reduces the absolute gas pressure within the enclosed interior space (12) to a value that enables a predetermined volume of the sample to be analyzed to enter without exhausting fluid from the interior space during entry of the predetermined volume of the sample to be analyzed.

18. the microbiological test method according to any one of claims 16 and 17, wherein said depressurization step reduces the absolute gas pressure within said closed interior space (12) to a value strictly less than the standard atmospheric pressure multiplied by the ratio of the final free volume in said interior space divided by the total volume of said interior space after the entry of a predetermined volume of said sample to be analyzed.

19. The microbiological test method according to any one of claims 16 to 18, wherein said depressurization step reduces said absolute gas pressure within said closed internal space (12) to a value strictly less than 600 mbar absolute pressure, preferably strictly less than 300 mbar absolute pressure, more preferably strictly less than 200 mbar absolute pressure, relative to a temperature of 25 ℃.

20. use of a microorganism testing device according to any one of claims 1 to 15 in a method for testing a liquid to be analyzed susceptible to containing at least one microorganism.

21. Use according to claim 20, characterized in that it comprises the following steps:

-connecting a container of a liquid to be analyzed to the inlet (40);

-an opening/closing member (46) opening the inlet (40) to enable the liquid to be analyzed to pass from the reservoir towards the closed inner space (12).

22. Use according to claim 21, characterized in that it comprises the following subsequent steps:

-said opening/closing member (46) closing said inlet (40);

-disconnecting the container of the liquid to be analyzed;

-incubating in the microbiological test device (10) the microorganisms potentially initially contained in the liquid to be analyzed.

23. Use according to claim 22, characterized in that it comprises a subsequent step consisting in visually detecting, counting, identifying and/or characterizing the microorganisms potentially initially contained in the liquid to be analyzed by observing the transparent portion of the chamber of the microorganism testing device (10).

Technical Field

The present invention relates generally to the field of microbiological analysis. It relates more particularly to a microbiological test device for testing a liquid to be analyzed, which liquid is liable to contain at least one microorganism. It also relates to a method of providing such a device and to the use of such a device in a method of testing a liquid to be analysed, which liquid is susceptible to containing at least one microorganism.

the invention relates more particularly to the field of microbiological testing in the food processing, pharmaceutical or cosmetic industry.

The invention was developed after benefiting from the research participated in by the national space research Center (CNES) [ french national space research center ].

background

there are many instances where it is attempted to test a liquid for the presence of at least one microorganism, usually in order to be able to notice the absence of such a microorganism.

Of course, the liquid to be analyzed may be a biological liquid (whole blood, serum, plasma, urine, cerebrospinal fluid, organ secretions, etc.). Nevertheless, the liquid may also be an industrial liquid, in particular a food liquid (water, beverages in general, in particular fruit juices, milk, soda, etc.) or a pharmaceutical or cosmetic liquid.

A number of laboratory techniques are known which make it possible to filter the liquid to be analyzed to collect the microorganisms which may be contained in the liquid, culture them so as to be able to detect them subsequently, count them, characterize them and/or identify them. These techniques require a number of processing operations well known to those skilled in the laboratory.

In these techniques, it is generally necessary to use a filtration device comprising an enclosed interior space bounded by a chamber and configured to receive the liquid to be analyzed. This technique is particularly called "membrane filtration". A microbial filtration member, such as a filtration membrane, is disposed in the enclosed interior space and separates a first compartment from a second compartment of the enclosed interior space within the enclosed interior space. The device comprises an inlet for the liquid to be analyzed, which inlet opens into a first compartment enclosing an inner space.

In known filtering devices, such as those of document EP-1.783.494, a suction opening is provided, which is configured to be connected to an external suction source. Thus, in the use of such devices, it is necessary to connect an external source of suction to the suction inlet in order to create a negative pressure within the enclosed interior space when the liquid to be analysed is introduced into the device via the inlet, such negative pressure facilitating, or even being necessary for, filtration.

Once filtration has taken place, the microorganisms are retained on the filter member, the device is opened to recover the filter member, and the filter member is transferred to a culture device to enable incubation of the microorganisms.

This technique is readily performed in the laboratory.

However, this technique is difficult to perform in an operating environment, particularly an industrial environment where liquids are produced, packaged, dispensed, or used. Indeed, in such a case, it would be beneficial to be able to have elements for detecting potential contamination of the liquid by undesirable microorganisms. However, the usual techniques as described above require the transport of the liquid sample to be analysed to a laboratory where the usual methods can be carried out. In fact, it is difficult to envisage carrying out these usual operations on site in an industrial field to produce, package, distribute or use liquids. This is because handling contaminated liquids in such environments poses the risk of propagating contamination if not handled correctly. Furthermore, the step of culturing any microorganisms that may be present requires the presence of a nutrient medium, which by definition promotes the growth of the microorganisms. Of course, the introduction of such nutrient media in such industrial environments is undesirable. Furthermore, the usual detection techniques also require protection of the sample to be analyzed from any external contamination, and therefore work in an environment as sterile as possible to avoid false positives.

disclosure of Invention

It is therefore an object of the present invention to propose a device and a method for microbiological testing of a liquid to be analyzed, which enable particularly simplified testing operations, even if use or performance outside a microbiological laboratory, including use or performance in an industrial environment, can be envisaged.

To this end, the invention proposes, firstly, a microbiological testing device for testing a liquid to be analyzed, the liquid being liable to contain at least one microorganism, the device comprising:

-an enclosed interior space bounded by a chamber and configured to receive a liquid to be analyzed;

-a microbial filtration member disposed in the enclosed interior space and separating a first compartment from a second compartment of the enclosed interior space within the enclosed interior space;

-an inlet for a liquid to be analyzed, the inlet opening into a first compartment enclosing an inner space.

Such a device is characterized in that, in a configuration for providing a microbiological testing device prior to use, the microbiological testing device comprises, within the closed inner space, a nutrient layer comprising a component of a microbiological culture medium, the nutrient layer being in contact with the filter means, and in that the inlet of the microbiological testing device comprises an opening/closing means, and in that, in a configuration for providing a microbiological testing device prior to use:

-the opening/closing member of the inlet is in a closed state for closing the inlet and closing the inner space in a gastight manner;

The absolute gas pressure inside the closed internal space, with respect to the temperature of 25 ℃, is strictly less than the standard atmospheric pressure of 1 bar at 25 ℃, so that the device is able to generate suction through the inlet during the first opening of the opening/closing member.

Other optional features of the device according to the invention, used alone or in combination:

in a configuration for providing a microbiological testing device prior to use, the closed internal space is isolated from any external source of suction.

The second compartment of the enclosed interior space is free of ports in fluid communication with the exterior of the enclosed interior space.

-in a configuration for providing a device prior to use, the microbiological media of the nutritive layer is dehydrated.

Any fluid exchange between the first and second compartments enclosing the inner space is performed by the filter member.

The microbiological testing device comprises a support for the filtering means and the nutrient layer.

The support for the filter member comprises a screen, for example in the form of a perforated plate, which extends through the closed inner space between the first and second compartments.

The nutrient layer is arranged between the filter member and the support for the filter member.

The nutrient layer is locally fixed between the filtering member and the support for the filtering member.

the support for the filtering member comprises a support baffle arranged in the second compartment.

-the supporting partition is perforated to enable fluid flow on either side of said partition in the second compartment.

-a water absorbent material is arranged in the second compartment.

The opening/closing member of the inlet comprises a valve.

The opening/closing member of the inlet comprises a leakproof membrane and is brought into an open state by rupturing the membrane.

The chamber of the microbiological testing device comprises at least one body at least partially delimiting the second compartment and comprises a lid at least partially delimiting the first compartment, the body and the lid being formed by separate parts assembled together to form the microbiological testing device.

The chamber of the microbiological testing device comprises at least one transparent portion.

The inlet comprises a distributor comprising several individual channels for the liquid to be analyzed.

The inlet comprises an inner portion of the first compartment leading to the closed inner space and an outer portion for connection to a container of the liquid to be analyzed, and the opening/closing member of the inlet is interposed between the inner and outer portions of the inlet.

In a configuration for providing a microbiological testing device prior to use, the absolute gas pressure within the closed inner space enables, during the entry of the predetermined volume of sample to be analyzed, the entry of the predetermined volume of sample to be analyzed without the exit of fluid from the inner space. In particular, the absolute gas pressure within the closed inner space is preferably strictly less than the standard atmospheric pressure times the ratio of the final free volume in the inner space after entry of the predetermined volume of the sample to be analyzed divided by the total volume of the inner space. In practice, in the configuration for providing a microbiological testing device prior to use, the absolute gas pressure within the closed interior space is strictly less than 600 mbar absolute, preferably strictly less than 300 mbar absolute, more preferably strictly less than 200 mbar absolute.

The present invention also relates to a method of providing a microbiological test device for testing a liquid to be analyzed susceptible to containing at least one microorganism, the method comprising providing a microbiological test device comprising:

-a chamber arranged for defining an enclosed interior space configured to receive a liquid to be analyzed;

-a microbial filtration member arranged to be disposed in the enclosed interior space and to separate the first compartment from a second compartment of the enclosed interior space within the enclosed interior space;

An inlet for a liquid to be analyzed, the inlet opening into a first compartment enclosing an inner space,

Wherein the method includes providing a nutritive layer configured to receive a composition of a microbiological culture medium impregnated within the enclosed interior space, the nutritive layer in contact with the filter member.

And in that, before connecting the microbiological testing device to the container of the liquid to be analysed, the method comprises, in this order, in sequence:

-a pressure reduction step to reduce the absolute gas pressure within the enclosed interior space;

-a closing step of closing the closed inner space in a gastight manner.

The invention also relates to the use of a microbiological test device having one of the above-mentioned features in a method for testing a liquid to be analyzed, which liquid is liable to contain at least one microorganism.

The use may further comprise the steps of:

-connecting a container of a liquid to be analyzed to the inlet;

-an opening/closing member opening the inlet to enable the passage of the liquid to be analyzed from the reservoir towards the closed inner space.

it may also include subsequent steps including:

-an opening/closing member closing the inlet;

-disconnecting the container of liquid to be analyzed;

-incubating the microorganisms, which may initially be contained in the liquid to be analyzed, in the microorganism testing device.

It may comprise further subsequent steps including visual detection, counting, identification and/or characterization of the microorganisms that may be initially contained in the liquid to be analyzed by observing the transparent portion of the chamber of the microorganism testing device.

drawings

various other characteristics emerge from the following description with reference to the attached drawings, which show, by way of non-limiting example, embodiments of the subject of the invention.

fig. 1 is an exploded perspective view of a first exemplary embodiment of a device according to the present invention.

Fig. 2 is a perspective view of the assembled device of fig. 1.

Fig. 3 is a cross-sectional view of the device of fig. 2, the cross-section being shown in fig. 1.

Fig. 4 is a perspective view from below of the cover of the device of fig. 1.

Fig. 1-4 depict exemplary embodiments of a microbiological testing device 10 for testing a liquid to be analyzed that is susceptible to containing at least one microorganism.

Fig. 5 is an exploded perspective view of a second exemplary embodiment of a device according to the present invention.

Fig. 6 is a perspective view from below of the body and the additional bottom of the second exemplary embodiment of the device according to the present invention.

fig. 7 is a cross-sectional view of the device of fig. 5, the cross-section being shown in fig. 5.

Detailed Description

For the purposes of the present invention, the term microorganism specifically encompasses gram-positive or gram-negative bacteria, yeasts, amoeba, viruses and, more generally, unicellular organisms which are invisible to the naked eye and which can be handled and propagated in the laboratory.

According to a preferred embodiment of the invention, the microorganism is a gram-negative or gram-positive bacterium or yeast.

The microbiological testing device, a first exemplary embodiment of which is depicted in fig. 1 to 4 and a second exemplary embodiment of which is depicted in fig. 5 to 7, has, in its operating state depicted in fig. 2 and 3 of the first exemplary embodiment and fig. 7 of the second exemplary embodiment thereof, a closed inner space 12, which closed inner space 12 is delimited by a chamber and is configured to receive a liquid to be analyzed. The two exemplary embodiments depicted will be described substantially simultaneously. When they occur, reference will be made to features that distinguish them from each other.

In the depicted example, the chamber of the microbiological testing device includes at least one body 14 and a lid 16. The body 14 and the lid 16 are formed from separate components that are assembled together to form the chamber of the microbiological testing device. A lid 16 encloses the body 14 to define the enclosed interior space 12 of the microbiological testing device 10. Thus, the cover 16 has a shape complementary to the shape of the body 14 so as to provide for its closure.

in the depicted example, the body 14 has a bottom wall 18 and a peripheral side wall 20 such that the body 14 is open through an end opposite its bottom wall 18. In the depicted example, the peripheral sidewall 20 has a central axis a 1. In the depicted case, the bottom wall 18 is a transverse wall perpendicular to the central axis a1 of the body 14. In the first exemplary embodiment, the bottom wall 18 is produced as a single piece together with the peripheral side wall 20, whereas in the second exemplary embodiment, the bottom wall 18 is produced in the form of a separate piece, which closes off the closed interior space 12 from the bottom. In the case where the bottom wall 18 is produced in the form of a separate component, it may be assembled to the peripheral side wall 20 in any known manner, for example by simple tight fitting, by gluing, by welding, by tightening with clips for mechanical connection, etc., and then a seal may be provided to ensure that when the bottom wall 18 is assembled to the peripheral side wall 20, it closes off the closed interior space 12 in a leak-proof manner.

For clarity of description, in the remainder of the description, considering that central axis a1 is oriented vertically and that bottom wall 18 is disposed at the lower end of the microbiological testing device, peripheral side wall 20 extends upwardly from bottom wall 18 in the direction of axis a 1. However, the verticality, levelness and the concepts of "top", "bottom", "upper" and "lower" are only used with reference to the orientation of the microbiological testing devices relative to each other as shown in the figures, and do not have a limiting effect on the scope of the present invention or the orientation of the microbiological testing devices in use.

The peripheral sidewall 20 is, for example, a surface that rotates about a central axis a 1. In the depicted example, the sidewall 20 is substantially cylindrical. However, other forms may be proposed.

thus, the lid 16 has a transverse wall 22 perpendicular to the central axis a1, in which case the transverse wall 22 has a substantially circular shape corresponding to the geometry of the upper edge 24 of the peripheral side wall 20 of the body 14. In the depicted example, the lid 16 has a cylindrical skirt 26, in this case a cylinder that rotates about a central axis a1, that extends downwardly from a lower surface of the lid's transverse wall 22. The cylindrical skirt 26 is configured to engage within the upper end of the peripheral sidewall 20 of the main body 14 in a vertical direction along the central axis a 1.

it should be noted that in the first exemplary embodiment, the upper end of the peripheral side wall 20 of the main body has a lateral recess on the inner surface that defines the annular bearing surface 28 of the upturned central axis a 1. The cylindrical skirt 26 has a lower edge 30, the lower edge 30 facing the annular bearing surface 28 when the cap 16 is assembled on the body 14.

The microbiological testing device 10 according to the present invention includes a microbiological filtration member 32, the microbiological filtration member 32 being disposed within the enclosed interior space 12 and separating the first compartment 12a from the second compartment 12b of the enclosed interior space 12 within the enclosed interior space.

In the depicted example, first compartment 12a is at least partially defined by cover 16, while second compartment 12b is at least partially defined by body 14.

Indeed, the microbial filtration member 32 extends substantially transversely within the enclosed interior space 12 along any cross-section of the enclosed interior space. In this example, the microbial filtration member 32 has a substantially planar shape, in this case a disc shape. It is preferably arranged perpendicular to the central axis a 1.

in the first depicted example, the microbial filtration member 32 has a peripheral edge 34 that has the same shape and the same dimensions as the cross-section of the inner surface of the peripheral sidewall 20 of the body 14. In the first depicted example, the peripheral edge 34 is configured to directly or indirectly axially abut downward against the annular bearing surface 28 of the body 14. As shown below, in the first depicted example, the peripheral edge 34 of the microbial filter element 32 is preferably arranged to be axially secured between the lower edge 30 of the cylindrical skirt 26 of the cover 16 and the annular bearing surface 28 of the body 14.

The microbiological testing device includes a nutrient layer 36 impregnated with a composition of microbiological media within the enclosed interior space 12, the nutrient layer 36 being in contact with the microbiological filtration member 32.

in the depicted embodiment, nutritive layer 36 is a separate element from microbial filtration member 32, while nutritive layer 36 is in contact with microbial filtration member 32. Once the device is assembled, nutritive layer 36 and microbial filtration member 32 are in contact with each other within the microbial testing device.

In this case, the nutrient layer 36 is preferably located below the microbial filtration member 32 under the conditions as set forth above. In this case, the nutritive layer 36 is located in the second compartment 12b enclosing the interior space 12. However, under the conditions as set forth above, there is nothing to prevent the nutritive layer from being located above the microbial filtration member 32. In this particular case, the nutritive layer advantageously comprises at least one chromogenic and/or fluorogenic substrate which enables the direct or indirect detection of the enzymatic or metabolic activity of the target microorganism. The visual signal generated by the at least one substrate is then visible through at least a portion of the thickness of the nutritive layer.

In the depicted example, the nutritive layer 36 has a substantially planar shape, in this case a disc shape. Nutritive layer 36 has a peripheral edge 38 that preferably mates with peripheral sidewall 34 of microbial filtration member 32. Thus, the nutritive layer 36 and the filter member 32 have the same shape. This means that, in the first depicted example, the peripheral edge 38 may be inserted axially downward against the annular bearing surface 28 between the annular bearing surface 28 of the body 14 and the peripheral edge 34 of the microbiological filtration member 32. In the first depicted example, the peripheral edge 38 of the nutritive layer 36 is preferably arranged to be axially secured with the peripheral edge 34 of the microbial filter element 32 between the lower edge 30 of the cylindrical skirt 26 of the lid 16 and the annular bearing surface 28 of the body 14.

For the purposes of the present invention, nutritive layer 36 comprises a support containing a microbiological culture medium.

The support may be based on various absorbent compounds, preferably with very high water retention capacity, for example rayon, cotton, natural or chemically modified cellulose fibers, such as carboxymethyl cellulose, absorbent or superabsorbent chemical polymers, such as polyacrylate salts, acrylate/acrylamide copolymers. Such a support member may be impregnated with a microbial culture medium in liquid form. Such a microbial culture medium can advantageously be dehydrated, i.e.have an "AW" (water activity) incompatible with microbial growth. Alternatively, the support may be coated or impregnated with the microbial culture medium or a component thereof in powder form under dry conditions. Alternatively, the liquid impregnation may be supplemented by adding powder after dewatering.

"microbial culture medium" is configured to mean a culture medium comprising the nutrient elements necessary for the survival and/or growth of the microorganism, in particular one or more from the group of carbohydrates, including sugars, peptones, growth factors, mineral salts and/or vitamins, etc. In practice, the skilled person will select the microbial culture medium as a function of the target microorganism according to criteria well known and within the grasp of the skilled person.

The nutrition layer 36 may contain optional additional elements such as:

-one or more selective agents, such as inhibitors or antibiotics, to promote the growth and development of one specific microbial species/strain relative to another;

-buffer, stain.

In general, nutritive layer 36 may also contain a substrate capable of detecting the enzymatic or metabolic activity of a target microorganism by a directly or indirectly detectable signal. For direct detection, the substrate may be linked to a moiety that serves as a fluorescent or chromogenic label. For indirect detection, the nutrition layer according to the invention may also comprise a pH indicator which is sensitive to pH changes caused by substrate consumption and shows the growth of the target microorganism. The pH indicator may be a chromophore or a fluorophore. As examples of chromophores, mention will be made of neutral red, aniline blue, bromocresol blue. Fluorophores include, for example, 4-methylumbelliferone, hydroxycoumarin derivatives, or resorufin derivatives. Thus, the fluorescent PC-PLC substrate that is preferentially used in carrying out the method of the invention corresponds to 4-methylumbelliferyl choline phosphate (4 MU-CP).

according to a preferred embodiment of the present invention, the microbiological media of the nutrition layer 36 is dehydrated in a configuration for providing a microbiological testing device prior to use. In this case, the nutritive layer 36 may be subjected to a calendaring operation after drying the support impregnated with the nutritive layer with the dehydrated microbial culture medium. The calendering by the generated pressure and heating temperature enables the dehydrated microbial culture medium to be stably retained and maintained in the support member of the nutritive layer over time, ensuring that the nutritive elements and optional additional elements remain in the nutritive layer.

Calendering of the nutrition layer 36 also enables a smooth and flat surface of the nutrition layer to be obtained. Calendering can also accelerate rehydration of the nutritional layer as compared to a non-calendered nutritional layer due to the compression of the nutritional layer thereby induced. In the case of a support formed from fibres, this compression, combined with the presence of a dewatering medium within the nutrition layer 36, greatly increases the capillary capacity of the nutrition layer, resulting in its almost instantaneous rehydration. This may also contribute to the suction phenomenon of the individual microbial filtration members 32 arranged against their surface. Thus, microbial filtration member 32 may be pressed against nutritive layer 36, ensuring that there is no space or reduced space between the two, which facilitates optimal microbial growth and/or survival over the entire surface of microbial filtration member 32. Thus, when microbial filtration member 32 is separated from nutritive layer 36, the presence of adhesive members therebetween (e.g., the presence of an adhesive layer) may be avoided. This represents a significant advantage, as such a bonding member will slow the passage of nutrient elements and optional additional elements from the rehydrated nutrient layer 36 to the microorganisms present on the microbial filtration member 32, thereby reducing the chances of growth and/or survival of these microorganisms.

The microbial filtration member 32 comprises a water permeable filter which retains microorganisms, particularly at its surface. With microbial filtration member 32 separated from nutrient layer 36, microbial filtration member 32 is permeable to nutrient elements and optional additional elements contained in nutrient layer 36 located below microbial filtration member 32. Such a filter may include a porous body, which may be formed of a material having properties thereof by its properties, its size, its spatial arrangement. Such porous bodies may have these properties by the arrangement of the pores.

the microbial filtration member 32 may, for example, be based on one or more materials from latex, polytetrafluoroethylene, poly (vinylidene fluoride), polycarbonate, polystyrene, polyamide, polysulfone, polyethersulfone, cellulose, a mixture of cellulose and nitrocellulose, or derivatives of these materials. Preferably, the microbial filtration member 32 is produced in the form of a porous membrane that is permeable to the nutrient elements and optional additional elements contained in the nutrient layer 36 and is capable of retaining microorganisms on its surface. Preferably, the microbial filtration member 32 covers the entire nutritive layer 36. Applicants have found that currently marketed microfiltration membranes for water (often referred to as liquids) typically have the properties required for use as the microbial filtration member 32. They make it possible to obtain good tear resistance, controlled porosity, smooth surfaces, thinness and a high level of hydrophilicity for the majority of the time during processing. Their color is usually white, which makes it possible to optimize the differentiation of colored colonies on their surface. Exploiting the filtering capacity and the hydrophilicity of such a filter membrane enables and optimizes the passage of the nutrient elements and optional additional elements present in the nutrient layer (optionally after rehydration thereof) towards the upper surface of the microbial filtration member 32, while preventing or limiting the migration of bacteria, yeasts and the like filtered at the upper surface of the microbial filtration member 32 in the opposite direction. For the purposes of the present application, the abovementioned filtration membranes are referred to without distinction as "filtration membranes", "microfiltration membranes" or "filtration membranes", these expressions being synonymous with one another. These filter membranes are included in the group formed by porous membranes.

The microbial filtration member 32 allows the elements of the nutrient medium and selective agents or reagents to pass through. Advantageously, the filtering member comprises pores having a diameter comprised between 0.01 and 0.8 microns, preferably between 0.2 and 0.6 microns, so as to retain bacteria, yeasts and moulds on their surface. According to a particular embodiment, the filter member comprises pores having a diameter between 0.25 and 0.6 microns, such as between 0.3 and 0.6 microns, or between 0.4 and 0.6 microns. Alternatively, this may be a layer without measurable pores, such as a dialysis membrane.

For example, the microbial Filtration member may be a "Fisher brandt General Filtration membranes" Filtration Membrane sold by Fisher Scientific Company l.l.c,300industrial drive, pittsburgh, PA 15275, USA, or a "nitrocellulose Membrane filter" Filtration Membrane manufactured by Zefon International, inc.,5350SW 1st Lane, Ocala, FL 34474, USA, or similar Membrane.

In some variations, the nutrient layer may be integral with the microbial filtration member 32, which serves as a support for the microbial culture medium. In this case, it will be understood that the nutrient layer is in contact with the microbial filtration member 32.

the microbiological testing device 10 according to the invention comprises an inlet 40 for the liquid to be analyzed. The inlet 40 enables liquid to be analyzed to be introduced into the enclosed interior space defined by the chamber when the microbiological testing device 10 is assembled such that the chamber defines the enclosed interior space, such as when the cover 16 is assembled with the body 14, the source of liquid being from outside the enclosed interior space 12.

In the depicted exemplary embodiment, the inlet 40 comprises an inner portion 42, which inner portion 42 opens into the first compartment 12a of the enclosed inner space 12, and an outer portion 44 for connection to a container of the liquid to be analyzed, which container may be, for example, a syringe, a tube, a bag, a funnel, etc.

in the depicted example, the inlet 40 is vertically disposed along a central axis a 1. The inlet is advantageously arranged on the cover 16, in this case for example in the centre of its transverse wall 22.

The inner portion 42 of the inlet 40 may comprise a distributor 56, the distributor 56 comprising several individual channels for the liquid to be analyzed. Such a distributor 56 facilitates distribution of the liquid to be analyzed, introduced via inlet 40, over a greater portion of the surface area of the microbiological filtration member 32. Particularly with the configuration of the exemplary embodiment, the inner portion 42 of the inlet 40 may include a distributor 56 having orifices, each opening at least partially in a radial direction relative to the central axis a1, the orifices preferably being angularly distributed to the right about the central axis a1 of the inlet 40.

The external connection portion 44 of the inlet 40 may include elements for coupling to a container. The external connection portion 44 itself may have a funnel shape. The external connection portion 44 may also include mechanical docking means for docking the container at the inlet 40.

The microbiological testing device 10 includes an opening/closing member 46, which opening/closing member 46 is, in the exemplary embodiment, interposed between the inner portion 42 and the outer portion 44 of the inlet, so as to block the inlet 40, preventing any circulation of gas between the closed inner space 12 of the microbiological testing device 10 and the outside through the inlet 40 in the closed state of the opening/closing member.

Preferably, the inlet 40 is a reclosable port. In this case, as depicted, the opening/closing member 46 may include a valve. Such a valve may preferably be brought from the open state to the closed state a number of times in succession and back again.

In some cases, the opening/closing member may include a leakage-proof film, and the opening/closing member may be in an open state by rupturing the film. In this case, the membrane cannot be reclosed. In this case, the inlet 40 may be re-closed by a second opening/closing member added to the external connection portion 44. Such a second opening/closing member (not shown) may be formed, for example, by a cap, a leakproof film or a plug.

It should be noted that such a second opening/closing member may also be provided in the case where there is an opening/closing member of the valve type as described above. Such second opening/closing means make it possible, for example, to reinforce the air-tightness, in particular the air-tightness, of the valve and, in particular, the long-term air-tightness during storage of the device 10 before use.

in both cases, such second opening/closing member makes it possible to protect the inlet from any contamination during storage of the device 10 before use.

In the depicted example, once assembled, the microbiological testing device 10 includes only a single port, in this case the inlet 40, for fluid communication between the enclosed interior space 12 and the exterior. In the depicted example, it will be noted that the second compartment 12b of the enclosed interior space 12 has no ports in fluid communication with the exterior of the enclosed interior space. However, this does not prevent the microbiological testing device 10 from being able to include several ports for fluid communication, including the inlet 40, all of which open into the first compartment 12a of the enclosed interior space. .

In the exemplary embodiment, microbial filtration member 32 has a reduced thickness relative to its length. For example, the diameter of the filter member is greater than 50 mm, for example between 80 mm and 100 mm. The thickness is of the order of a few millimetres, typically less than 5 millimetres.

It is also advantageous to provide the microbiological testing device 10 with a support 48 including a support for the microbiological filtration member 32 and for the nutrition layer 36.

Support 48 allows microbial filtration member 32 and nutrient layer 36 to be held in place between first compartment 12a and second compartment 12 b.

In the first exemplary embodiment depicted, support 48 for microbial filtration member 32 and for nutrition layer 36 includes a support partition 50 disposed in second compartment 12 b.

for example, the support baffles 50 may be planar in shape, each disposed in a radial plane containing the central axis a 1. They may, for example, extend from the bottom wall 18 of the body 14 and have an upper edge 52 against which the microbial filtration member 32 and the nutrient layer 36 may directly or indirectly rest vertically downward. In the first example depicted, each support baffle 50 extends radially across the entire second compartment 12b, and is therefore laterally bounded by two diametrically opposed portions of the peripheral sidewall 20 of the body 14. In this particular embodiment, it will be appreciated that the support baffle 50 performs its supporting function by virtue of its upper edge 52. In the depicted example, the upper edges 52 of the support baffles 50 all extend in the same transverse plane perpendicular to the central axis a 1.

Between them, however, supporting partitions are between them, in the second compartment 12b, delimiting a subsection of this second compartment 12 b. Such a supporting partition 50 may be perforated to enable fluid flow on either side of the partition in the second compartment 12 b. In the depicted example, it is chosen to provide the supporting partition 50 with a through hole 54, the through hole 54 enabling fluid communication between two adjacent subsections of the second compartment 12b, which subsections are separated by one of these supporting partitions 50. These through holes 54 are optional. In the depicted example, they are produced in the form of slits which extend from a low point located substantially halfway the second compartment 12b in the direction of the central axis a1 and which open in an open manner in the upper edge 52. These through holes can have completely different geometries and are produced, for example, in the form of holes, in particular circular holes. They do not necessarily lead to the upper edge 52.

In the depicted example, the supporting bulkhead 50 also makes it possible to mechanically strengthen the chamber of the device, in particular to make it more resistant to the pressure difference between the inside and the outside of the chamber.

The support 48 for the microbial filtration member 32 can be produced in different ways. Producing different effects. It may for example be produced in the form of a screen extending in a transverse plane perpendicular to the central axis a 1. Such a screen may be supported, for example, by bearing on a bearing surface 28 of the body 14. The support for the microbial filtration member 32 may be produced in the form of one or more posts extending vertically from the transverse bottom wall 18 of the main body 14 in the direction of axis a 1. The support for the microbial filtration member 32 may also be created in the form of one or more brackets extending transversely from the inner surface of the peripheral sidewall 20.

In a second example depicted in fig. 5 to 7, the support 48 for the filtering member comprises a screen 49. Such screens may be formed from intersecting wire meshes or intersecting bar meshes. In the example depicted in fig. 5 to 7, the screen is formed by a perforated plate extending perpendicular to the central axis a1 between the first and second compartments. In the depicted case, the screen 49 is produced as a single component with the peripheral sidewall 20 of the body 14. It will be appreciated that such a screen 49 in the form of a perforated plate provides better support for the microbiological filter element 32, especially if the latter is not very rigid. This results in better flatness of the microbial filtration member 32 and nutrient layer 36, especially when the filtration process is performed.

In the depicted example, the plate extends through the body 14 over its entire inner diameter. The plate has an annular outer peripheral portion 51, the annular outer peripheral portion 51 extending radially from the inner cylindrical surface of the peripheral sidewall 20 toward the central axis a 1. The peripheral portion 51 of the plate is solid, i.e. without perforations. The plate has a perforated central portion in the centre of which it forms a screen 49. The upper surface of the perforated central portion 49 is offset downwardly relative to the upper surface of the peripheral portion. In this way, the peripheral portion 51 defines a recess in the upper surface of the plate, the diameter of which corresponds to the diameter of the perforated central portion 49. In the depicted example, filter member 32 and nutritive layer 36 have an outer diameter that is equal to or less than the diameter of the recess. Thus, the filter member 32 and the nutritive layer 36 may be received in the recess, radially wedged in the recess. It should be noted that in this second exemplary embodiment, unlike the first exemplary embodiment, the filter member 32 and the nutritive layer 36 are not sandwiched between the cover 16 and the main body 14.

It is worth noting that in fig. 6, in a view from below, the second exemplary embodiment comprises a partition 53 in the second compartment 12b, which partition 53 has the same function and substantially the same geometry as the supporting partition of the first exemplary embodiment, except for the function of direct support of the filtering member.

The support 48 is dimensioned to form a limited resistance, or even a negligible resistance, to the flow of fluid between the first and second compartments enclosing the inner space. In the case of a perforated plate, for example, it will be ensured that the cumulative total surface area projected along the central axis a1 of the perforations 55 represents at least 30% of the surface area of the filter member 32, preferably at least 50% of the surface area of the filter member. The perforated plate has a plurality of perforations 55 distributed within a defined circle (the smaller circle containing all perforations) corresponding to at least 50%, preferably at least 70%, of the surface area of the filter member 32. In the example envisaged, the number of perforations 55 is greater than 20, preferably greater than 50. However, for larger perforations, and optionally with different geometries, such as stars, fans, etc., a smaller number of perforations may be used.

In the depicted example, the support 48 for the microbial filtration member 32 is produced as a single component with the body 14. However, such a support may be produced in the form of one or more separate parts. These components may simply be placed within the second compartment 12b or may be assembled to the body 14, for example, by bonding, welding, snapping, or interlocking.

in the depicted example, it should be noted that the nutritive layer 36 is disposed between the microbial filtration member 32 and the support 48 for the filtration member.

advantageously, a nutrient layer 36 may be provided to be locally secured between the microbial filtration member 32 and its support 48. For example, lid 16 may include bearing elements, e.g., corresponding to upper edges of one or more support baffles 50, such that when the microbiological testing device is assembled, microbiological filtration member 32 and nutrient layer 36 are secured between these bearing elements of lid 16 and supports 48. In the depicted example, dispenser 56 has such bearing elements on a lower surface for clamping the microbial filtration member 32 and nutrient layer 36 on a support 48 in the center of the microbial testing device.

In the depicted example, the volume of the second compartment 12b enclosing the interior space 12 is greater than the volume of the first compartment 12a enclosing the interior space. Preferably, the volume of the second compartment 12b enclosing the interior space 12 is at least twice the volume of the first compartment 12a enclosing the interior space 12, preferably at least three times the volume of the enclosed interior space 12 a. In one embodiment, for a device configured for analyzing a 100 ml sample, the volume of the second compartment 12b enclosing the inner space 12 is for example at least 100 ml, preferably more than 100 ml and less than 150 ml, in order to be able to contain the volume of all the liquid to be analyzed. The total volume of the enclosed interior space defined by the chamber is, for example, 120 ml to 300 ml, which is, for example, 150 ml.

In the configuration for providing the microbiological testing device 10 prior to use, the opening/closing member 46 is in a closed state to close the inlet 40 and enclose the interior space 12 in an airtight manner.

In this provided configuration, the microbiological testing device 10 is therefore closed in a leak-proof manner, without possible gaseous communication between the closed internal space 12 delimited by the chamber and the outside. In this provided configuration, the microbial filtration member 32 and the nutrient layer 36 are contained within the enclosed interior space 12 defined by the chamber, thereby forming a ready-to-use microbial testing device for filtering liquid to be analyzed so as to collect therefrom potential microorganisms on the microbial filtration member 32 and enable growth of such microorganisms for detection, enumeration, characterization and/or identification.

Furthermore, in this configuration for providing the microbiological testing device 10 prior to use, the absolute gas pressure within the enclosed interior space is at a reduced initial pressure value, enabling the device to generate suction through the inlet during the first opening of the opening/closing member 46.

As a result of the first two paragraphs, in this configuration for providing a microbiological testing device 10 prior to use, and therefore prior to introduction of a sample into the enclosed interior space 12 defined by the chamber, the microbiological filtration means 32 and the nutrient layer 36 comprising constituents of the microbiological culture media are contained within the enclosed interior space 12 defined by the chamber, and the absolute gas pressure within the enclosed interior space is at a reduced initial pressure value, enabling the device to generate suction through the inlet during the first opening of the opening/closing means 46.

for this purpose, the reduced initial pressure value of the absolute gas pressure in the closed interior space (12) is strictly less than the standard atmospheric pressure of 1 bar at 25 ℃ relative to the temperature of 25 ℃.

In practice, this suction phenomenon will be reflected by a predetermined amount of liquid entering the inner space of the device more quickly during the first opening of the opening/closing means than if the initial pressure in the inner space is equal to the atmospheric pressure.

It should be noted that the exact value of the reduced initial pressure need not be known exactly. In practice, this value is first determined so as to be sufficient to draw at least part or even all of the predetermined volume of sample to be analysed into the device.

Preferably, the value is determined to be sufficient to enable the device to aspirate a full predetermined volume of the sample to be analysed within the device without having to subject the sample to be analysed to a pressure greater than the standard atmospheric pressure to cause it to enter the device.

preferably, such a reduced initial pressure value is sufficiently low to enable the entire predetermined volume of the sample to be analyzed to enter into the interior space without draining fluid from the interior space during the entry of the predetermined volume of the sample to be analyzed. This makes it possible to ensure easy entry of the entire sample into the device. This also makes it possible to avoid any propagation to the outside of the elements initially contained in the device, in particular of the elements of the culture medium, during the entry of the sample into the device.

The person skilled in the art, by optionally supplementing the initial evaluation of some tests, will be able to determine the desired reduced initial pressure of the device as a function of the conditions envisaged for the use of the device (total volume of the enclosed internal space 12 defined by the chamber of the device, volume of the sample, temperature and pressure conditions at the time of use of the device, etc.).

The desired reduced initial pressure may be actually evaluated in the following manner. The total volume VT of the enclosed interior space 12 defined by the chamber is considered. A predetermined volume VE of the sample to be analyzed is then determined, which it is desired to be able to introduce into the device 10 for analysis. From which the final free volume VL in the inner space after the predetermined volume of sample to be analyzed has entered the inner space is then deduced. This final free volume VL is therefore equal to the total volume VT of the closed internal space 12 delimited by the chambers, from which the predetermined volume VE of the sample to be analyzed that is expected to be able to be introduced into the device 10 for analysis is subtracted:

VL＝VT–VE

The ideal gas law then applies as an approximation to the change in conditions in the closed internal space 12 defined by the chamber between the instant immediately before the entry of the sample and the instant immediately after the entry of this sample, assuming that only the liquid containing the sample is introduced without significant temperature changes. This entry of the sample is reflected by a pressure variation, from a reduced initial pressure value Pi, which is the absolute gas pressure value within the closed internal space in the configuration provided, to a final value Pf, which is the absolute gas pressure value within the internal space after the entry of the predetermined volume of sample to be analyzed.

Thus, the following equation is obtained:

Pf×VL＝Pf×(VT–VE)＝Pi×VT

this makes

Pi＝Pf×(VT–VE)/VT＝Pf×VL/VT

It follows that in a configuration for providing a microbiological testing device 10 prior to use, the absolute gas pressure within the enclosed interior space 12 (referred to as the reduced initial pressure) is preferably strictly less than atmospheric pressure multiplied by the ratio of the final free volume in the interior space after entry of a predetermined volume of sample to be analyzed divided by the total volume of the interior space.

The value of the standard atmospheric pressure can be fixed virtually arbitrarily at 1 bar at 25 ℃.

in practice, it is generally considered that the volume VE of the sample must be at least 20 ml, preferably at least 50 ml, more preferably at least 100 ml. On the other hand, it is generally considered that the volume VE of the sample must be 300 ml or less, preferably 200 ml or less, more preferably 150 ml or less.

In the case of a total volume VT of the interior space of the device of 150 ml, and for a sample with a volume VE of 100 ml, the above-described rapid calculation gives the desired reduced initial pressure, which is strictly less than 333 mbar absolute for the absolute gas pressure within the closed interior space 12 used in the construction of the device provided prior to use. In practice, however, it is preferable to provide a reduced initial pressure of strictly less than 300 mbar absolute, taking into account the approximations associated with the differences between the proposed assumptions and the experimental reality. More preferably, an initial pressure of strictly less than 200 mbar absolute will preferably be provided, in particular in order to facilitate rapid entry of the sample into the device.

It should be noted that for a total volume VT of 300 ml of the inner space of the device, a desired reduced initial pressure of strictly less than 666 mbar absolute is thus determined, preferably strictly less than 600 mbar absolute, more preferably strictly less than 400 mbar absolute.

It should be noted that the above values are indicative values, including indicative values for given and given usage conditions. In fact, it is better that the initial pressure drop in the device is actually less than the above value.

In practice, these values will be able to serve as a basis for developing a device according to the invention, and manufacturing conditions that will enable the device to operate correctly can be readily determined using some routine testing.

Thus, the above values can be measured by connecting a pressure gauge to the inlet of the inlet, as close as possible to the open/close member 46, even if this leads to uncertainties regarding the actual value of the reduced initial pressure, including if the uncertainties are as high as 50 mbar.

This means that when the microbiological testing device is prepared, an at least partial vacuum is created in the closed inner space. This at least partial vacuum can be generated, for example, by assembly under vacuum, or at least at a pressure less than or equal to the desired reduced initial pressure, in any case strictly less than 1 bar at 25 ℃, or by depressurizing the closed interior space after assembly of the microbiological test device.

it will be appreciated that in this configuration for providing the microbiological testing device 10 prior to use, the enclosed interior space is isolated from any external source of suction. This therefore explains the need to provide the chamber in its closed state and the inlet 40 is airtight, in particular airtight. This is achieved by any means known to the person skilled in the art.

In the depicted example, the cover 16 and the body 14 are thus assembled in an airtight manner.

The assembly may be a detachable assembly such that the microbiological testing device can be opened after its use without damage, for example to remove the microbiological filtration member 32. For example, the removable assembly may be produced using complementary threads disposed on the cap 16 and the body 16, respectively. In the depicted configuration, such complementary threads (not shown) may fit on the outer surface of the cylindrical skirt 26 of the cap 16 and the inner surface of the upper end of the peripheral sidewall 20 of the body 14, respectively. Another possible example of a detachable assembly can be obtained by a system of bayonet assemblies. Yet another example of a detachable assembly may be obtained by providing an external assembly flange or by providing screws for assembling the cover 16 on the body 14.

The assembly may be a non-detachable assembly that cannot be used to open the microbiological testing device 10 after its use without damage, for example by gluing, by welding or by riveting.

To provide the required gas tightness, in particular gas tightness, one or more seals (not shown) may be provided between the body 14 and the cover 16, especially in case of detachable assemblies.

in a configuration for providing a microbiological testing device prior to use, the microbiological media of the mesh layer 36 is advantageously dehydrated. Rehydration of the microbial culture medium at the time of use is then provided. This rehydration may be performed by the liquid itself to be analyzed.

indeed, the microbial filtration member 32 and the nutrient layer 36 are arranged such that any fluid exchange between the first compartment 12a and the second compartment 12b enclosing the interior space occurs through the microbial filtration member 32 and the nutrient layer 36. Thus, it may be impossible for fluid to flow from first compartment 12a to second compartment 12b bypassing microbial filtration member 32 or nutrient layer 36. In the depicted embodiment, this is due to the microbial filtration member 32 and the nutrient layer 36 extending through the entire portion of the enclosed interior space 12 of the microbial testing device between the first compartment 12a and the second compartment 12b of the enclosed interior space.

Advantageously, it may be provided that a water absorbing material is arranged in the second compartment. In the depicted example, such material may be disposed within one, several, or all sections of the second compartment 12b between the support partitions 50. The water-absorbing material can be based on various absorbent compounds, preferably with very high water retention capacity, for example rayon, cotton, natural or chemically modified cellulose fibers, such as carboxymethyl cellulose, absorbent or superabsorbent chemical polymers, such as polyacrylate salts, acrylate/acrylamide copolymers. Thus, this material is available from industry Absorbent Co, 1Moody Lane, Grimsby, DN 312 SS, UK under the trade designation "Super Absorbent Fiber".

The chamber of the microbiological testing device may advantageously be made of a polymeric material. However, other materials are possible, including at least partially glass. In the depicted example, the body 14, the cover 16, and the support 48 may be made of the same material or different materials.

Preferably, the chamber of the microbiological testing device comprises at least one transparent portion. In particular, the transparent portion may be arranged such that an observer may see at least a portion of the upper surface of the microbial filtration member 32 facing the first compartment 12 a. Preferably, the transparent portion is arranged so that an observer can see all of the upper surface of the microbial filtration member 32 facing the first compartment 12 a. This is because any potential microorganisms are visible on this surface after incubation. In the depicted example, the transparent portion of the chamber is thus preferably arranged at least in the transverse wall 22 of the cover 16. The entirety of the cover 16 may be transparent. In some embodiments, it will be provided that the entire chamber is made of a transparent material. The transparent part of the chamber is made of, for example, Polymethylmethacrylate (PMMA) or glass.

thus, the microbiological testing device as described above is configured for use in a method of testing a liquid to be analyzed susceptible to containing at least one microorganism.

In such use, the microorganism testing apparatus is provided in advance in a configuration provided before use. As mentioned above, in this configuration the microbiological testing device has the microbiological filtration means 32 and the nutrient layer 36 housed in a leaktight manner in the closed internal space 12 and in which the negative pressure level prevails, this negative pressure level corresponding to a reduced initial pressure, in any case to the absolute gas pressure inside the closed internal space, strictly less than 1 bar with respect to a temperature of 25 ℃.

In order to provide a microbiological test device for testing a liquid to be analyzed which is liable to contain at least one microorganism, it is first necessary to provide a microbiological test device comprising, as described above:

A chamber arranged to delimit an enclosed internal space 12 configured to receive a liquid to be analyzed, for example in the form of a body 14 and a lid 16;

A microbial filtration member 32 arranged to be arranged in the enclosed interior space 12 and to separate the first compartment 12a from the second compartment 12b of the enclosed interior space in the enclosed interior space;

An inlet 40 for the liquid to be analyzed, arranged to open into the first compartment 12a of the closed inner space, the inlet can for example comprise an inner portion 42 and an outer connecting portion 44, the inner portion 42 being arranged to open into the first compartment 12a of the closed inner space.

further, the method provided prior to use includes providing a nutritive layer 36, the nutritive layer 36 configured to be received within the enclosed interior space and including a component of the microbiological media, the nutritive layer 36 configured to be in contact with the filtration member. As noted above, the nutritive layer 36 may be separate from the microbial filtration member 32, or, as a variation, the nutritive layer and the microbial filtration member may be provided integral with one another.

According to the invention, the method for providing a microbiological testing device in the configuration for providing, before any use, and therefore before any connection with a container of the liquid to be analyzed, comprises in this order, in succession:

a depressurization step to reduce the absolute gas pressure within the enclosed interior space 12;

A closing step of closing the closed internal space 12 in a gastight manner.

It should be noted that at the time of the depressurization step, the microbiological testing device 10 including the above-described elements may have been assembled such that the chamber is closed and contains the above-described elements. In this case, the depressurization step can be carried out by connecting the enclosed interior space 12 of the microbiological testing device, for example, via the inlet 40, to a source of suction, for example, a vacuum pump, the inlet 40 thus being in an open state. The pressure is thereby reduced to the desired reduced initial pressure, which is in any case strictly less than 1 bar with respect to the temperature of 25 ℃.

In another variant, the depressurizing step may be accompanied by an assembling step. Indeed, in the example depicted, it is possible to provide, for example, an assembly of the cover 16 on the body 14, which makes it possible to close the chamber and thus to delimit the closed internal space 12, this assembly being possible at an absolute gas pressure which is equal to or less than the desired reduced initial pressure, i.e. in particular a pressure strictly less than 1 bar with respect to a temperature of 25 ℃.

In the first case, the closing step may comprise closing the valve of the inlet 40 or placing a sealing membrane, as long as there is still an absolute gas pressure equal to or less than the desired reduced initial pressure. In the second case, the closing step may comprise assembling the lid 16 on the body 14 in a leaktight manner, which makes it possible to close the chamber. In this case, the opening/closing member of the inlet 40 is preferably in a closed state in advance.

Thus, a microbiological testing device 10 is obtained which is configured to position the microbiological filtration member 32 and the nutrient layer 36 within the closed internal space 12 delimited by the chamber, the closed internal space 12 being at a predetermined initial level of negative pressure, called reduced initial pressure, and which corresponds to a gas pressure in the closed internal space which is less than a predetermined threshold value, itself strictly less than standard atmospheric pressure, for example an absolute pressure of 200 mbar with respect to 25 ℃.

It should be noted that in this provided configuration, the microbiological testing device can be stored, transported, etc., and in this provided configuration, the liquid to be analyzed is not introduced into the enclosed interior space 12 of the microbiological testing device.

The use of the microbiological testing device according to the invention corresponds to the introduction of the liquid to be analyzed into the closed internal space 12 through the inlet 40. This introduction generally corresponds to the connection of the container in which the liquid to be analyzed is found to the inlet 40. This connection may take various forms, simply assuming that a fluid connection is established between the container and the inlet 40. Preferably, the connection is a fluid-tight connection, and preferably a gas-tight, in particular a gas-tight, connection. Such connection may include a mechanical interface between the container and the inlet 40.

Thus, the use of the microbiological test device according to the invention comprises the following steps:

Connecting a container of the liquid to be analyzed to the inlet 40, in particular to the external connection portion 42 of the inlet 40 in the exemplary embodiment;

an opening/closing member 46 that opens the inlet to enable the liquid to be analyzed to pass from the container towards the closed inner space 12 of the microbiological testing device.

The step of opening the inlet opening/closing member 46 is the first opening of the opening/closing member after the closing step for closing the closed inner space 12 in a leakproof manner during the supply process.

In this step, a predetermined initial level of negative pressure has a particularly important role. In fact, the presence of this negative pressure facilitates the introduction of the liquid to be analyzed into the closed internal space 12 of the microbiological testing device. On the one hand, this is due to the phenomenon of suction being exerted on the liquid to be analyzed if it is initially, for example, at atmospheric pressure. On the other hand, this is because the negative pressure of the predetermined level is reflected by the presence of a small amount of gas in the microbiological test device before the introduction of the liquid to be analyzed, so that the microbiological test device does not have to discharge a corresponding amount of gas during the introduction of the liquid to be analyzed. This not only facilitates the entry of the liquid to be analyzed into the closed inner space of the microbiological testing device, but also avoids the discharge of particles or molecules initially contained in the microbiological testing device to the outside.

It should be noted that during this step of using the microbiological testing device, the closed internal space 12 can be isolated from any external source of aspiration, during the opening of the opening/closing member enabling the passage of the liquid to be analyzed from the container to the closed internal space 12. In fact, before the first opening of the device following the closing step of closing the closed internal space 12 in a leaktight manner during the supply process, the suction is advantageously obtained by means of the reduced initial pressure present in the device.

Thus, the introduction of the liquid to be analyzed into the microbiological testing device 10 according to the invention through the inlet 40 enables the liquid to be first introduced into the first compartment 12a of the closed inner space 12, and then the liquid to be analyzed naturally comes into contact with the microbiological filtration member 32. The liquid to be analyzed is thus filtered by the microbial filtration member 32 such that at least some potential microbes, especially those for the intended test, are retained by the microbial filtration member 32. On the other hand, the liquid part of the liquid to be analyzed migrates towards the second compartment 12b of the closed inner space 12. To this end, it should be understood that, at least for this step, the microbiological testing device is advantageously in the orientation shown in the figures, with the second compartment 12b enclosing the internal space 12 below the first, these two compartments being separated from each other by a microbiological filtration member 32, which in the example depicted extends along a plane that is then horizontal.

The liquid to be analyzed enables rehydration of the nutritive layer 36. Because the nutritive layer 36 is in contact with the filtration member, the nutritive elements and optional additional elements thereof may migrate toward the microorganisms retained by the microbial filtration member 32. Thus, if the microbiological testing device 10 is placed in a favourable environment, in particular temperature, an incubation of the microorganisms can be obtained within the microbiological testing device 10 itself, without having to open the microbiological testing device 10, in any case without having to remove the microbiological filtration means 32 from the chamber of the microbiological testing device 10.

Thus, after the step of introducing the liquid to be analyzed into the enclosed interior space 12 of the microbiological testing device, the use of the microbiological testing device 10 according to the present invention may include the following subsequent steps:

An opening/closing member 46 closing the inlet 40;

-incubating the microorganisms, which may initially be contained in the liquid to be analyzed, in the microorganism testing device.

After this incubation period, the use may comprise a subsequent step comprising visual detection, counting, identification and/or characterization of the microorganisms that may be initially contained in the liquid to be analyzed, in particular by observing the transparent part of the chamber of the microbiological testing device. Here again, this testing step may be performed without the need to open the microbiological testing device 10, the microbiological filtration member 32 upon which the potential microorganisms are located, thereby remaining within the enclosed interior space of the microbiological testing device 10.

The invention is not limited to the examples described and depicted, since various modifications may be made thereto without departing from the scope of the invention.