WO2017089911A1

WO2017089911A1 - Product for microbiology, and related kit and preparation method of solid or semi-solid culture media using a microwave oven

Info

Publication number: WO2017089911A1
Application number: PCT/IB2016/056242
Authority: WO
Inventors: Francesca PIEMONTI
Original assignee: Bioside S.R.L.
Priority date: 2015-11-25
Filing date: 2016-10-18
Publication date: 2017-06-01
Also published as: ITUB20155884A1

Abstract

A product for microbiology (10) for the preparation in a microwave oven of solid or semi-solid culture media, comprises a bag (100) suitable for use in a microwave oven equipped with: a compartment (103) containing a dehydrated culture medium (200) containing a thickener and/or gelling agent; a (102) compartment containing a liquid (300) for the reconstitution of the medium; a vent (900) for the discharge of the excessive pressure generated in the bag (100) during the preparation in the microwave oven. The relative method for the preparation of the medium provides for placing the bag (100) containing the reconstituted medium in a microwave oven and heating the medium to a suitable temperature to activate the gelling agent and thickener.

Description

DESCRIPTION

"PRODUCT FOR MICROBIOLOGY, AND RELATED KIT AND PREPARATION METHOD OF SOLID OR SEMI-SOLID CULTURE MEDIA

USING A MICROWAVE OVEN"

[0001] The present invention relates to a product for microbiology, and in particular a bag for the preparation of solid or semi-solid culture mediums using a microwave oven .

[0002] The cultivation of microorganisms in the laboratory aims to make large quantities of biological material available so as to adequately develop laboratory investigations and for example allow practical applications in which microorganisms are involved.

[0003] These microorganisms are made to reproduce on suitable substrates, called culture media and fed with appropriate nutritional substances. The use of solid or semi-solid media makes it possible to isolate colonies of microorganisms and thus analyse the phenotype, as well as to create suitable conditions for the mobility of said microorganisms .

[0004] Solid and semi-solid culture media are obtained from a solution of various chemical components (synthetic and / or natural) , at defined concentrations, in purified water or water of equivalent quality or in other aqueous solutions. These media have a different composition in relation to the specific nutritional needs of the microorganisms cultivated.

[0005] The solid or semi-solid culture media are prepared starting from respective broths to which a thickener and gelling agent is added, in suitable proportions.

[0006] Careful preparation of the solid or semi-solid culture media is a crucial step for ensuring the integrity of a microbiological examination.

[0007] In the sector the use of dehydrated preparations for solid or semi-solid media is known of, which has the great advantage of a long duration (shelf-life of years) and no special storage or transportation requirements (at room temperature) . When solid or semi-solid dehydrated media are used the operations related to their preparation must be properly performed to avoid alterations of the components and microbial contamination. In particular, the preparation steps required are: weighing the chemical components, determining and adding the volume of liquid, dissolving and dispersion, heating to appropriate temperatures (depending on the gelling agent used, it is essential to mix and activate the thickener and gelling agent), measurement and adjustment of the pH, sterilisation, cooling (to suitable temperatures, depending on the gelling agent used) , possible addition of selective agents and / or growth factors, dispensing (in tubes, bottles, dishes or capsules which the sample for cultivation is placed in) . The sterilisation step is generally performed in an autoclave, at a temperature of about 120°C for 15 minutes, unless indicated otherwise in the production sheets of some types of medium which require the use of lower temperatures (around 100 ⁰ C) for a longer time (20 minutes) . It is therefore evident that the preparation of solid and semi-solid culture media from dehydrated components has considerable drawbacks: considerable expenditure in terms of time (at least two hours to reach the dispensing step) ; high costs, since expensive equipment is required (scales, autoclave, glassware) and accessories (flasks, filters) which must be cleaned and sterilised or thrown away if disposable; high risk of contamination or of operator error in the preparation phase.

[0008] In order to speed up the preparation of solid and semi-solid culture media it is known of to use bottles (glass) containing media already in solid or semi-solid form, which only need to be dissolved, have any additives added and dispensed. However, the step of dissolving the ready medium to permit the dispensing thereof must, in any case, be carried out in an autoclave, with the consequent expenditure of time (at least an hour to reach the dispensing step) and energy. Moreover, such bottles ready for use are normally made of glass, and are therefore heavy and awkward to carry, dangerous for the operators, and constitute voluminous waste at the end of use. The bottles containing media already in solid or semi-solid form have the further drawback of a short duration (shelf-life of a few weeks) and strict storage and transport requirements (at refrigerated temperatures) .

[0009] The object of the present invention is to provide a product for microbiology for the preparation of solid or semi-solid media able to overcome the drawbacks of the prior art .

[0010] In particular, the object of the present invention is to provide a product for microbiology for the preparation of solid or semi-solid media able to drastically reduce the time needed to prepare the medium.

[0011] In addition, the object of the present invention is to provide a product for microbiology for the preparation of solid or semi-solid media able to eliminate any risk of external contamination.

[0012] Furthermore, the object of the present invention is to provide a product for microbiology for the preparation of solid or semi-solid media able to maintain unaltered its characteristics for a considerable length of time and without the need to be refrigerated for storage.

[0013] Such object is achieved by a product for microbiology for the preparation of solid or semi-solid media using a microwave oven according to claim 1, by a kit according to claim 13, and by a method for the preparation of solid or semi-solid media using a microwave oven according to claim 14. The dependent claims describe preferred or advantageous embodiments of the product and the method.

[0014] The characteristics and advantages of the product for microbiology according to the present invention will be evident from the description given below, by way of a non- limiting example, according to the appended drawings, wherein :

[0015] -figure 1 shows a front view of a product for microbiology for the preparation of solid or semi-solid media using a microwave oven according to the present invention, in one embodiment;

[0016] -figure 2 shows an embodiment variant of the product for microbiology in figure 1;

[0017] - figure 3 shows a product for microbiology according to the present invention, in a further embodiment;

[0018] -figure 4 shows an embodiment variant of the product for microbiology in figure 3;

[0019] - figure 5 shows a product for microbiology according to the present invention, in yet a further embodiment;

[0020] - figure 6 shows an embodiment variant of the product for microbiology in figure 5; [0021] - figures 7 and 8 show a product for microbiology according to the present invention, in further embodiments and provided with accessories;

[0022] - figures 9 and 10 show some examples of use of the product for microbiology according to the present invention for the preparation of solid or semi-solid media using a microwave oven; figure 9 summarises the information on the manner in which the tests were conducted, and figure 10 summarises the information on the results obtained.

[0023] With reference to the appended drawings, and in particular to figure 1, a product for microbiology for the preparation of solid or semi-solid media using a microwave oven is shown, indicated by reference numeral 10.

[0024] The product for microbiology 10 comprises:

[0025] - a container 100 suitable for use in a microwave oven and equipped with a compartment 101 provided with a venting element 900 (hereinafter simply called vent 900) adapted to allow the discharge of the excessive pressure generated in the container 100 during the preparation of the culture medium in the microwave oven; said vent element guarantees the perfect integrity of the container 100 and allows it to operate in safe conditions;

[0026] - a dehydrated solid or semi-solid culture medium 200.

[0027] The dehydrated solid or semi-solid culture medium 200 is a set of chemical components (synthetic and / or natural) at defined concentrations in the exact and predefined quantity necessary for the specific use. In particular, the dehydrated solid or semi-solid culture medium 2 0 0 contains a thickener and gelling agent activated by the rise in temperature (heating) .

[0028] Preferably, the thickener and gelling agent is agar (such as Gelidium or Gracilaria or Pterocladiae) , or gelatine, or polyacrylamide, or algin or alginate, or silica gel .

[0029] The dehydrated culture medium 2 0 0 is in solid form, for example in powder or granules, or tablets, or in capsules .

[0030] In an alternative embodiment, the dehydrated culture medium 2 0 0 already comprises within it at least one supplement 4 0 0 (of the type that tolerates microwaves, such as ampicillin or kanamycin) .

[0031] The container 1 0 0 is a bag made of flexible material and suitable for use in a microwave oven.

[0032] The container 1 0 0 is made of polymeric material, such as polyolefin (e.g. PE Polyethylene and Polypropylene PP) , Polyethylene terephthalate (PET) , crystalline polyethylene terephthalate (CPET) , polylactic acid (PLA) , polyvinyl alcohol (PVOH / PVA) , polybutylene succinate (PBS ) , ethyl- vinyl alcohol polymer (EVOH) . [0033] Preferably the bag is made of a multi-layer material comprising one or more barrier layers, water and air-proof, adapted to improve the conservation of the content and to preserve the sterility thereof.

[0034] Preferably the bag is made of a multi-layer material comprising a barrier layer partially or totally impermeable to light to avoid the deterioration of any photosensitive substances.

[0035] Preferably, the bag is made of transparent or partially transparent or non-transparent, or partially or totally coloured, plastic material.

[0036] The bag 100 comprises an upper end 110 and a lower end 120.

[0037] Preferably (as shown in the figures 2, 4, 6, 7, 8) the bag 100 is provided, at the upper end 110, with at least one grip portion 160 by means of which it is possible to firmly and safely grasp the bag 100.

[0038] The grip portion 160 is composed of a portion of the bag 100 in which both walls of the bag are welded together. Consequently, the grip portion 160 is isolated from the rest of bag 100 since it does not come into contact with the culture medium which, after preparation in a microwave oven, is at a high temperature. Consequently, by means of the grip portion 160 the bag 100 can be held without getting burned. [0039] Preferably, the grip portion 160 is provided with a hole 161, suitably dimensioned, to further facilitate the grip and to enable the bag to be hung possibly from a hook.

[0040] Preferably, the grip portion 160 is provided at the opposite end with an outlet channel 180, to facilitate dispensing of the culture medium.

[0041] Preferably, the bag 100, at the lower end 120, comprises a "stand up" system (for example a fold, this allows the bag to maintain a vertical position without the need for other supports.

[0042] In an alternative embodiment (shown in figures 1, 2, 3, 4, 7, 8), the product for microbiology 10 comprises a compartment 102 containing a liquid 300 needed to reconstitute the dehydrated culture medium 200.

[0043] The liquid 300 is, for example, purified water or water of equivalent quality or another aqueous solution.

[0044] During the production of the product for microbiology 10, the bag 100 with compartment 102 containing the liquid 300 is subjected to sterilisation prior to marketing.

[0045] The sterilisation step is carried out for example by gamma radiation means and more generally, by irradiation, or with moist heat or other sterilisation techniques suitable for the purpose.

[0046] The laboratory technician thus has available a product for microbiology 10 ready for use. The bag 100 filled with liquid 300 can be stored for a long time before use since the culture medium has not yet been reconstituted given that the compartment 102 containing the liquid 300 is separated from the compartment 101 containing the dehydrated medium 200.

[0047] In an embodiment variant (shown in figures 5 and 6) , the product for microbiology 10 comprises an empty compartment 102 adapted to be filled via a filling channel 130, with a liquid 300 required for the reconstitution of the dehydrated culture medium 200 .

[0048] On the outer side of the bag 100, the filling channel 130 is closed by a seal 133. Moreover, once the compartment 101 has been filled, the channel 130 is hermetically sealable, for example with a cap. This makes it possible to still have a closed and sterile bag 100. Preferably, the cap is provided as an accessory of the bag, sterilised and individually packaged.

[0049] During the production of the product for microbiology 10, the bag 100 with compartment 102 (for the liquid 300) is subjected to sterilisation prior to marketing.

[0050] The laboratory technician thus has available a product for microbiology 10 comprising an empty compartment 102 adapted to be filled, through the channel 130, with the liquid 300 required for the reconstitution of the dehydrated culture medium 200. The empty bag 100 can thus be stored for a long time before use.

[0051] When necessary, the laboratory technician fills the compartment 102 with the sterile liquid 300 needed to reconstitute the culture medium. Once the compartment 102 has been filled the laboratory technician closes the channel 130 with the cap, so as to still have a closed and sterile bag 100 which can be stored easily in uncontrolled environments. Even the bag 100 filled with liquid 300 can thus be stored for a long time before use since the culture medium has not yet been reconstituted.

[0052] The bag 100 is provided with an outlet channel 180 to allow dispensing of the reconstituted medium (when still in liquid form) into smaller containers intended to host the sample to be analysed (Petri dishes, vials, tubes and so forth) .

[0053] In an embodiment variant (shown in figures 1 and 2), the outlet channel 180 is made by removing an end 111 of the upper portion 110. In such example, the bag is provided with at least one incision 114 (or in any case a weakened portion) adapted to facilitate the opening of the outlet channel 180.

[0054] In an embodiment variant (shown in figures 3-8), the outlet channel 180 is closed by a seal 183 on the outside of the bag 100. Preferably, once the culture medium has been partially dispensed the outlet channel 180 can be closed with a cap. In one embodiment, the cap is a measuring cap used to dispense the exact amount of medium required .

[0055] In an embodiment variant, shown in figures 5 and 6, the outlet channel 180 coincides with the filling channel 130.

[0056] The bag 100 is suitable for preparing from 100 ml (for the dispensing of 5-8 Petri dishes) to 9, 000 ml of medium, even up to 20,000 ml of medium. Preferably, the bag 100 is suitable to be made in different formats.

[0057] In an embodiment variant (shown in figures 1, 3-8), the dehydrated culture medium 200 is housed in a further compartment 103 made in the container 100.

[0058] In this variant, the compartment 102 (containing the liquid 300 or empty and intended to be filled with the liquid 300 via the filling channel 130) and the compartment 103 containing the dehydrated culture medium 200 are kept separate by at least one yielding separation means 105.

[0059] Preferably, the separation means 105 is a yielding weld or gluing made between the two walls of the bag 100. Preferably, the yielding weld is the weld at least partially separating the two compartments 102,103. In this variant the yielding weld or gluing is adapted to be opened, unglued, to connect the compartments 102,103 and permit reconstitution of the medium. [0060] In a further embodiment variant not shown, the container 100 (or bag) comprises a plurality of further compartments 103 containing additional chemical components (synthetic and / or natural) in defined concentrations.

[0061] As shown in the figures, the further compartment 103 containing the dehydrated culture medium 200 is devoid of the filling channel. In fact, in the production process of the product for microbiology 10, one side of the compartment 103 of the bag 100 remains open, even partially, so as to allow easy filling with the solid dehydrated culture medium 200. Once filled, the further compartment 103 is closed, for example by welding the walls, to ensure the integrity of the content.

[0062] Once the further compartment 103 has been filled and closed, the bag 100 is subjected to sterilisation before marketing .

[0063] In an embodiment variant (shown in figure 2), the dehydrated culture medium 200 is housed outside the container 100, for example inside a compartment 202 provided in a capsule 201, external and separate from the container 100.

[0064] In this variant, the bag 100 is provided with an inlet mouth 180, closed by a seal 183.

[0065] The capsule 201 is engageable, for example by screwing or snap or pressure fitting, to the inlet mouth 180 provided on the bag 100.

[0066] The step of engaging the capsule 201 to the mouth 180 permits the connection between the compartments 102, 202 and the reconstitution of the culture medium.

[0067] Advantageously also, once the capsule 201 has been engaged to the mouth 180, the mouth 180 is closed hermetically, and this makes it possible to once again have a closed and sterile bag 100.

[0068] In yet another embodiment variant, the product for microbiology 10 comprises a plurality of capsules 201 each containing chemical components (synthetic and / or natural) at defined concentrations corresponding therefore to a given dehydrated culture medium 200.

[0069] The container 100 has a compartment 101 provided with at least one vent element 900 adapted to allow the escape of the pressurised vapour generated during the preparation of the culture medium in a microwave oven.

[0070] Preferably, the vent element 900 is provided at the upper end 110.

[0071] In one embodiment, the vent element 900 is for example a hole 901, made in a wall of the bag 100, completely covered (to ensure the sterility of the bag 100) by a peelable seal 902 suitable to peel off, by effect of the pressurised vapour inside the bag, and at least partially free the hole 901 (variant in figures 1 and 2) . [0072] In a further embodiment, the vent element 900 is made at a yielding weld 904, made between two opposite walls of the bag 100, and provided with a through hole 903 (passing transversely through the bag) . The yielding weld 904 is adapted to yield, by effect of the pressurised vapour inside the bag, and to allow the passage of the vapour as far as the hole 903 (variant in figures 3 and 4) .

[0073] In yet a further embodiment, the vent element 900 is a yielding weld 905, made between two opposite walls of the bag 100 at an outer edge. The yielding weld 904 is adapted to yield, by effect of the pressurised vapour inside the bag, and to allow the passage of the vapour towards the outside (variant in figures 5 and 6) .

[0074] In a yet further embodiment, the vent element 900 is a valve 906 made at the seal 183 of the outlet channel 180. The valve 906 is adapted to open, by effect of the pressurised vapour inside the bag, and to allow the passage of the vapour towards the outside (variant in figure 7) .

[0075] In a yet further embodiment, the vent element 900 is a micro-perforated portion 907 provided in the wall of the bag. The micro-perforated portion 907 is provided with micro holes adapted to open, by effect of the pressurised vapour inside the bag, and to allow the passage of the vapour towards the outside (variant in figure 8) .

[0076] Preferably, the container 100 is provided with a thermometric band 118, preferably reversible, adapted to detect the temperature of the culture medium inside the bag 100. Advantageously, the thermometric band 118 makes it possible to accurately and instantly determine the temperature of the medium suitable for the addition of the supplements 400, if any. Moreover, the thermometric band 118 makes it possible to accurately and instantly determine the temperature of the medium suitable for dispensing.

[0077] Preferably, the container 100 is provided with a volumetric band 117, adapted to detect the volume of the culture medium inside the bag 100. Advantageously, the volumetric band 117 allows the dispensing of the culture medium in a constant volume without the use of external devices. Moreover, the volumetric band 117 allows the identification of how much culture medium is contained in the bag and, with good approximation, how many constant volumes can be obtained.

[0078] Preferably, the container 100 is equipped with a radio frequency identification band 119 (henceforth referred to as RFID or Radio-Frequency IDentification) band adapted to permit the identification and / or automatic storage of information on the culture medium contained in the bag 100. Advantageously, the container 100 equipped with the RFID band 119 allows automation of the preparation process in a microwave oven of the culture medium. In fact, the heating time in the microwave and the power required are predefined and stored in the RFID band 119 for each type of culture medium and for each volume of medium contained in the bag. In addition, the RFID band 119 automatically sends the time / power parameters to the microwave oven. This guarantees a high reproducibility of the medium and remarkable ease of use of the product for microbiology 100, in addition to full product traceability .

[0079] Preferably, the product for microbiology 100 comprises an outer seal 800 adapted to ensure the tightness over time of the yielding separation means 105 (or yielding weld) . Preferably, the outer seal 800 is a spring clip, for example plastic, externally applied to the bag 100, above the yielding separation means 105. In particular, the outer seal 800 helps to withstand the thrust exerted by the liquid 300 against the yielding separation means 105.

[0080] Preferably, the product for microbiology 100 comprises a supplement 400 housed outside the container 100, for example inside a compartment 402 provided in a capsule 401, external and separate from the container 100.

[0081] The supplement 400 is composed of one or more chemical components (synthetic and / or natural) such as a selective agent (for inhibiting the development of undesired microorganisms) or a buffering agent (for example to maintain a stable pH) , or a growth factor, or a differential agent.

[0082] The capsule 401 is engageable, for example by screwing or snap or pressure fitting, to the inlet mouth 180 provided on the bag 100, or to the outlet channel 180, or to the filling channel 130.

[0083] In another embodiment variant, the product for microbiology 10 comprises a plurality of capsules 401, each containing a particular supplement 400.

[0084] At the moment of use of the culture medium, the laboratory technician implements the connection between the compartment 102 (filled with liquid 300) and the segment 103, 202 containing the dehydrated culture medium 200 for the reconstitution of the medium.

[0085] With reference to the variant shown in figures 1 and 3-8, the laboratory technician breaks the seal made by the yielding separation means 105 (namely the yielding welding or gluing) , and specifically, separates the two walls of the bag 100 previously joined together, thus enabling the dehydrated culture medium 200 to come into contact with the liquid 300 and dissolve in it. Note that at this point the bag 100 is still closed and sterile.

[0086] With reference to the variant of figure 2, the laboratory technician engages the capsule 201 to the mouth 180 far enough to break the seal 183 between the compartments 102,202 , for example by screwing or snap or pressure-fitting, thus allowing the dehydrated culture medium 200 to come into contact with the liquid 300 and dissolve in it. Note that at this point the bag 100 is still closed and sterile.

[0087] Given that the reconstitution of the medium takes place without the need to open the bag, once reconstituted, the medium is still in a closed and sterile bag 100.

[0088] Once the dehydrated medium is dissolved, the activation step of the thickener and gelling agent takes place via the microwave. In particular, the heating of the dissolved medium is achieved by inserting the container (or bag 100) in a microwave oven.

[0089] The object of the present invention also relates to a method for the preparation using a microwave oven of a solid or semi-solid culture medium, comprising the steps of:

[0090] -preparing a bag 100 provided with a compartment 103 containing a dehydrated culture medium 200 containing a thickener and/or gelling agent activated by heating, and a compartment 102 containing a liquid 300 for the reconstitution of the dehydrated culture medium 200;

[0091] -reconstituting the medium by combining the dehydrated culture medium 200 with the liquid 300;

[0092] -inserting the bag 100 containing the reconstituted medium in a microwave oven, and heating the reconstituted medium in a microwave oven at a temperature suitable to activate the thickener and gelling agent.

[0093] The method for preparing a solid or semi-solid culture medium using a microwave oven further comprises, after the step in the microwave oven, the additional steps of:

[0094] -cooling the reconstituted medium after its preparation in the microwave;

[0095] -adding to the medium still in liquid form a supplement 400 and/or dispensing at least partially the medium still in liquid form.

[0096] Preferably, the heating step in the microwave oven provides for heating to a temperature equal to or exceeding 100° C, preferably between 100° C and 110° C.

[0097] Ideally, the heating step of the reconstituted medium in a microwave oven provides for setting the microwave to a power between 300W and 1000W, preferably between 300W and 600W and even more preferably between 300W and 500W.

[0098] Preferably, the heating step of the reconstituted medium in a microwave oven provides for keeping the bag 100 inside the oven for between 300 and 600 seconds, preferably between 360 and 480 seconds.

[0099] Preferably, the cooling step provides for lowering the temperature to about 40 - 50 °C.

[00100] The cooling step can be performed for example in an incubator or heated thermostatic bath. In the case of a bag fitted with a thermometric band 118 no special equipment is needed and the bag can be left to cool on the work counter.

[00101] The culture medium can be directly dispensed or stored directly in the bag 100 for reuse. In the latter case, the culture medium, now solidified, may be dissolved (liquefied) again using the microwave oven.

[00102] Figures 9 and 10 show two summary tables of examples of use of the product for microbiology according to the present invention for the preparation using a microwave oven of solid or semi-solid culture media.

[00103] The table in figure 9 shows different settings of the microwave oven (in terms of the set power expressed in watts and length of time spent in the microwave oven expressed in seconds) used for the preparation of different types of medium, with or without the addition of a supplement. The table in figure 10 summarises, for each preparation test conducted, a qualitative assessment of the medium obtained, evaluated both when extracted from the oven and still in liquid phase (LIQUID MEDIUM RATING) or solidified after cooling (SOLID MEDIUM RATING) . Additionally, an assessment of the quality of the final solid or semi-solid medium obtained inside the dispensing support, as required by the regulations for quality control, is expressed.

[00104] From the examples shown it can be seen that the best results are achieved, depending on the type of medium used, with the following settings of the microwave oven:

[00105] -Plate Count Agar (PCA) : power approximately 320 watts and time about 420 seconds;

[00106] -Dichloran Rose Bengal Chloramphenicol (DRBC)

Agar-: power approximately 320 watts and time about 420 seconds ;

[00107] -Violet Red Bile Agar (VRBL) : power 320-400 watts and time 420-480 seconds;

[00108] -Agar Listeria : power 320-400 watts and time

420-480 seconds:

[00109] -Baird Parker Agar: power 320-400 watts and time

450 - 480 seconds;

[00110] -Tryptic Soy Agar (TSA) : power 320-400 watts and time 420-480 seconds;

[00111] -Xylose Lysine Desoxychlorate (XLD) Agar: power

320-400 watts and time 420-480 seconds.

[00112] The product for microbiology 10 is especially suitable for the preparation of solid or semi-solid culture media for diagnostic use in the food, cosmetic, pharmaceutical, environmental, clinical, medical, veterinary spheres and other areas of microbiological diagnostics . [00113] The present invention also relates to a kit for microbiology 1 comprising a product for microbiology 10 and a plurality of capsules 201, engageable to the container 100, each containing a dehydrated culture medium 200 and/or a plurality of capsules 401, engageable to the container 100, each containing a supplement 400.

[00114] Such a kit allows the laboratory technician to select the dehydrated culture medium 200 and/or the supplement 400 needed for the specific cultivation of microorganisms, in situ.

[00115] Innovat ively , a product for microbiology for the preparation in a microwave oven of solid or semi-solid culture media according to the present invention drastically reduces (to a few minutes) the time needed to prepare the medium.

[00116] Advantageously, a product for microbiology for the preparation in a microwave oven of solid or semi-solid culture media according to the present invention makes it possible to entirely eliminate the risk of external contamination during the preparation step.

[00117] Advantageously, a product for microbiology according to the present invention (in the variant comprising a dehydrated culture medium and a bag with a compartment filled with liquid) enables the laboratory technician to have a product ready for immediate use, transportable and storable at room temperature and in any case with a long life (shelf-life of even 24 months) .

[00118] Advantageously, a product for microbiology according to the present invention (in the variant comprising a dehydrated culture medium and a bag with an empty compartment and filling channel) permits a reduction of transport and storage costs thanks to the reduced dimensions. Moreover, such product has a very long life (shelf-life of years) even at room temperature, without alteration of its characteristics.

[00119] Summarising in points the advantages of a product for microbiology according to the present invention, such product:

[00120] -drastically reduces (from several hours to a few minutes) the time needed to prepare a solid or semi^¬ solid culture medium;

[00121] -has a very long shelf life (even years) ;

[00122] -saves time in weighing chemical components

(thanks to the presence of the pre-measured dehydrated culture medium and any supplements) ;

[00123] -drastically reduces energy consumption;

[00124] -permits improved analytical performance since the sterilisation process used does not produce heat stress

(overheating) ;

[00125] - can be used to prepare any type of medium, with or without supplements;

[00126] -does not require the purchase of expensive equipment (e.g. does not require an automatic dispenser);

[00127] -allows transport and storage at room temperature ;

[00128] -allows quick loading of the liquid directly in situ; the liquid can be pumped directly from the storage tank (without the need to be dosed into more manageable and/or predefined volumes) and loaded directly through the filling channel; the use of RFID technology (which informs the peristaltic pump of the exact volume of liquid to be loaded) also serves to facilitate and standardise the filling process; allows multiple loading sessions, namely the filling of several bags with liquid in single session (weekly, monthly, yearly, according to the needs of the laboratory) without altering its shelf-life (the liquid loaded remains separate from the dehydrated culture medium) . The laboratory can fill the bags according to its needs and the availability of space in the warehouse.

[00129] -the use of RFID technology permits automatic recognition of the type of medium to be prepared, the relative process parameters (automated setup of heating power, heating time, duration parameters) and transmission of said parameters to the microwave oven, this permits standardisation and automation of the preparation process; [00130] -allows, thanks to the presence of the thermometric indicator, quick and accurate identification of the temperature suitable for supplementation and dispensing;

[00131] Summarising in points the advantages of a kit for microbiology according to the present invention, such product in addition to the above:

[00132] -permits a selection of the culture medium and/or dehydrated supplement when needed;

[00133] -ensures maximum management flexibility of the workload (bags independent of the medium) . The system does not "impose" pre-selection of the type of medium which can therefore be chosen at the moment of actual use.

[00134] It is clear that a person skilled in the art may make modifications to the product and method described above, all contained within the scope of protection as defined by the following claims.

Claims

1. Product for microbiology (10) for the preparation of solid or semi-solid culture media using a microwave oven comprising :

- a dehydrated solid or semi-solid culture medium (200) and containing a thickener and/or gelling agent activated by heating;

- a closed bag (100), provided with a compartment containing a liquid (300) needed to reconstitute the dehydrated culture medium (200) or an empty compartment (102) adapted to be filled via a filling channel (130), with a liquid (300) required for the reconstitution of the dehydrated culture medium (200);

wherein said bag (100) is suitable for use in a microwave oven and equipped with a vent (900) for the discharge of the excessive pressure generated inside the bag (100) during the preparation of the culture medium (200) in the microwave oven.

2. Product for microbiology (10) according to claim 1, wherein the thickening and/or gelling agent is agar or gelatine, or polyacrylamide or algin or alginate, or silica-gel .

3. Product for microbiology (10) according to claim 1 or 2, wherein the dehydrated culture medium (200) is housed in a compartment (103) made in the bag (100), said compartment (103) being kept separate from the compartment of the liquid (102) by at least one means of separation (105) yielding to permit the connection between the compartments (103,102) and the reconstitution of the medium .

4. Product for microbiology (10) according to claim 3 comprising an outer seal (800) applied externally to the bag (100) over the yielding means of separation (105) .

5. Product for microbiology (10) according to claim 1 or 2, wherein the dehydrated culture medium (200) is housed inside a compartment (202) provided in a capsule (201), engageable to an inlet mouth (180) provided on the bag (100) at the compartment (100), to permit the connection between the compartments (103,102) and the reconstitution of the medium.

6. Product for microbiology (10) according to any of the preceding claims, wherein the vent element (900) is a hole (901), made in a wall of the bag (100) and completely covered by a peelable seal (902) suitable to peel off, by effect of the increased pressure inside the bag, and to at least partially free the hole (901) .

7. Product for microbiology (10) according to any of the claims from 1 to 5, wherein the vent element (900) is a hole (903) made at a yielding weld (904) made between the walls of the bag, adapted to yield, by effect of the pressure inside the bag, and to free the passage as far as the hole (903) .

8. Product for microbiology (10) according to any of the claims from 1 to 5, wherein the vent element (900) is a weld (905) made between the walls of the bag (100), at an outer edge, yielding and adapted to yield by effect of the increased pressure inside the bag, and to free the passage outwards .

9. Product for microbiology (10) according to any of the claims from 1 to 5, wherein the vent element (900) is a micro-perforated portion (907) of the wall of the bag, provided with micro holes adapted to open, by effect of the increase in pressure inside the bag, and to free the outward passage.

10. Product for microbiology (10) according to any of the preceding claims, wherein the bag (100) is fitted with: a thermometric band (118), preferably reversible; and/or a volumetric band 117; and/or a band for radio frequency identification (RFID band) (119) .

11. Product for microbiology (10) according to any of the preceding claims, comprising a supplement (400), housed in a compartment (103) of the bag (100) or in a compartment (402) provided in an external capsule (401), said supplement (400) being a selective agent or a buffering agent or a growth factor or a differential agent.

12. Product for microbiology (10) according to any of the preceding claims, wherein the bag (100) is made of polymer material selected from the group comprising: Polyolefin, e.g. PE Polyethylene and Polypropylene PP, Polyethylene terephthalate (PET) , crystalline polyethylene terephthalate (CPET) , polylactic acid (PLA) , polyvinyl alcohol (PVOH / PVA) , polybutylene succinate (PBS ) , ethyl- vinyl alcohol polymer (EVOH) .

13. Kit for microbiology (1) comprising a product for microbiology (10) according to any of the preceding claims, and a plurality of capsules (201) engageable to the bag (100), each capsule (201) containing a dehydrated culture medium (200) and/or supplement (400) .

14. Method for the preparation of a solid or semi-solid medium using a microwave oven comprising the steps of: -preparing a bag (100) provided with a compartment (103) containing a dehydrated culture medium (200) containing a thickener and/or gelling agent activated by heating, and a (102) compartment containing a liquid (300) for the reconstitution of the dehydrated culture medium (200); -reconstituting the medium by combining the dehydrated culture medium (200) with the liquid (300);

-inserting the bag (100) containing the reconstituted medium in a microwave oven, and heating the reconstituted medium in a microwave oven at a temperature suitable to activate the gelling agent and thickener.

15. Method for the preparation of a solid or semi-solid culture medium using a microwave oven according to claim 14, wherein the step of heating the reconstituted medium in a microwave oven provides for setting the microwave oven at a power of 300W - 1000W, preferably 300W - 600W and keeping the bag (100) inside the oven for between 300 and 600 seconds, preferably between 360 and 480 seconds.

16. Method for preparing a solid or semi-solid culture medium using a microwave oven according to claim 14 or 15 further comprising, after the step in the microwave oven, the additional steps of:

-cooling the reconstituted medium after preparation in the microwave until a suitable temperature for the addition of a supplement (400);

-adding a supplement (400) to the medium still in liquid form .