Microbial limit test instrument for food detection

Abstract

This invention discloses a microbial limit detector for food testing, relating to the field of microbial detection technology. It includes a limit detector body with an annular platform mounted on its upper surface. A circular groove is formed on the upper surface of the annular platform, and multiple vertically arranged annular grooves are formed at the top edge of the circular groove. A retaining member is inserted into each vertical groove. A filter core is placed in the circular groove, and filter paper is placed on the upper surface of the filter core, contacting the retaining member. An annular groove is formed at the edge of the upper surface of the annular platform, and a sealing member is slidably connected within the annular groove. The inner surface of the upper end of the sealing member contacts the filter paper, and a suction flask is slidably connected to the inner annular surface of the sealing member. This invention uses a retaining structure consisting of a retaining rod, a retaining cylinder, and a retaining plug installed in the vertical grooves to hold the filter core in place. This prevents the filter core from being completely submerged in the circular groove, facilitating the removal of the filter paper and filter core from the circular groove after microbial sampling, thus reducing the probability of filter paper damage.

Description

Technical Field

[0001] This invention relates to the field of microbial detection technology, specifically to a microbial limit detector for food testing. Background Technology

[0002] Microbial limit analyzers are key equipment for food quality control, used to accurately determine the degree of microbial contamination in samples to ensure that products meet safety standards. Their core principle is based on membrane filtration: microorganisms in the test solution are trapped on the surface of a filter membrane with a specific pore size through negative pressure filtration, and then transferred to a culture medium for culture and colony counting, thereby quantitatively analyzing the microbial content. This technology is particularly suitable for liquids, soluble solids, and highly antimicrobial samples (such as beverages and condiments), and can efficiently separate microorganisms from matrix interference, improving the reliability of detection.

[0003] The process of using the microbial limit analyzer is as follows: First, sterilize the filter core and the parts of the analyzer that will come into contact with the liquid to be tested. After sterilization, place the filter core on the annular platform, then place the filter paper on the filter core, and then install the vacuum flask on the annular platform. Finally, pour the liquid to be tested into the vacuum flask, start the vacuum pump in the microbial limit analyzer, and extract the liquid from the vacuum flask through the filter core and filter paper, leaving the microorganisms on the filter paper. After the liquid in the vacuum flask is extracted, remove the vacuum flask, filter paper, and filter core in sequence. At this point, the filter paper can collect the microorganisms in the liquid in the vacuum flask.

[0004] In the use of conventional microbial limit analyzers, the filter core needs to be completely installed in the groove of the annular platform. This makes it difficult to remove the filter core from the annular platform after the experiment. Furthermore, when the filter paper is covering the filter core, it needs to be completely covered to ensure complete collection of microorganisms in the liquid in the filtration flask. After the experiment, the filter paper must be carefully removed from the filter core, and it must be ensured that the filter paper remains intact during the removal process. However, the filter paper is easily damaged when wet, making the entire experiment quite delicate. Summary of the Invention

[0005] The purpose of this invention is to provide a microbial limit tester for food testing, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A microbial limit detector for food testing includes a limit detector body. A drain component is installed inside the limit detector body, and a valve is installed within the drain component, extending to the front of the limit detector body. An annular platform is mounted on the upper surface of the limit detector body. A circular groove is formed on the upper surface of the annular platform. A through groove communicating with the drain component is formed at the bottom of the annular platform. Multiple vertically arranged annular grooves are formed at the top edge of the circular groove. A retaining member is inserted into the vertical groove. A filter core is placed in the circular groove, and filter paper is placed on the upper surface of the filter core, contacting the retaining member. An annular groove is formed at the edge of the upper surface of the annular platform, and a sealing member is slidably connected within the annular groove. The retaining member contacts the sealing member, and the lower end of the sealing member contacts the retaining member. The inner surface of the upper end of the sealing member contacts the filter paper. A vacuum filtration bottle is slidably connected to the annular inner surface of the sealing member.

[0007] Furthermore, the drainage component includes a vacuum pump, which is installed inside the limit instrument body. A water inlet pipe is installed at the input end of the vacuum pump, and a drain pipe is installed at the output end of the vacuum pump. Multiple vertical cylinders are installed on the upper side of the annular surface of the water inlet pipe. The end of the vertical cylinder away from the water inlet pipe is connected to a through groove, and the valve is installed inside the vertical cylinder.

[0008] Furthermore, the supporting member includes a supporting rod, which is inserted into the vertical groove and contacts the filter core. A supporting cylinder is sleeved on the lower end of the supporting rod, and the supporting cylinder is installed in the vertical groove. A supporting plug is installed on one end of the supporting rod in the through groove. The supporting plug is slidably connected in the supporting cylinder. An extrusion member is installed on the annular surface of the supporting cylinder, and the extrusion member contacts the sealing member.

[0009] Furthermore, the extrusion component includes a connecting cylinder, which is mounted on the annular surface of the supporting cylinder. An extrusion cylinder is installed on the side of the connecting cylinder away from the supporting cylinder. An extrusion plug is slidably connected inside the extrusion cylinder. An extrusion rod is installed on the upper surface of the extrusion plug. The end of the extrusion rod away from the extrusion plug is connected to a sealing component.

[0010] Furthermore, the sealing element includes an annular cylinder, which is installed in an annular groove. An annular plate is slidably connected in the annular groove. The extrusion rod passes through the annular cylinder and is connected to the annular plate. Multiple transverse grooves are formed on the inner surface of the annular plate. A pressing component is installed in the transverse groove. The lower surface of the pressing component is in contact with the filter paper. The suction filtration bottle is installed on the annular surface of the annular plate and is in slidable contact with the pressing component.

[0011] Furthermore, the pressing component includes a pressing cylinder, which is installed in a transverse groove. A pressing plate is slidably connected inside the pressing cylinder. A first elastic element is installed at one end of the pressing plate inside the pressing cylinder. The end of the first elastic element away from the pressing plate is installed inside the pressing cylinder. The lower surface of the end of the pressing plate away from the first elastic element is in contact with the filter paper. A pressure-receiving component is installed on the side of the pressing cylinder away from the filter paper. The pressure-receiving component is in contact with the filtration bottle and the pressing plate, respectively.

[0012] Furthermore, the pressure-receiving component includes a pressure-receiving block, which is installed inside the lower pressure cylinder. An inclined block is installed at one end of the pressure-receiving block inside the lower pressure cylinder. The inclined block slides in contact with the lower pressure plate, and the end of the pressure-receiving block away from the inclined block passes through the lower pressure cylinder and contacts the suction filtration bottle.

[0013] Furthermore, a pushing block is installed on the lower surface of the pressure plate, and the pushing block slides in contact with the filter paper.

[0014] Furthermore, a pressure relief cylinder is installed at the end of the connecting cylinder away from the supporting cylinder, and a balance plug is slidably connected inside the pressure relief cylinder. A second elastic element is installed on the side of the balance plug away from the connecting cylinder, and the end of the second elastic element away from the balance plug is installed inside the pressure relief cylinder.

[0015] Furthermore, a sealing ring is installed on the inner surface of the annular plate, and the filtration bottle slides in contact with the sealing ring.

[0016] The microbial limit detector for food testing provided by this invention has the following beneficial effects: 1. This invention uses a supporting structure consisting of a supporting rod, a supporting cylinder, and a supporting plug installed in a vertical groove to support the filter core placed in a circular groove, preventing the filter core from being completely submerged in the groove. This facilitates the removal of the filter paper and filter core from the groove after microbial sampling, reducing the probability of filter paper damage. Furthermore, a squeezing structure consisting of a connecting cylinder, a squeezing cylinder, a squeezing plug, and a squeezing rod is installed on the supporting structure. The supporting structure squeezes the squeezing structure, and the squeezing structure pushes the annular plate upward, thus creating space for the filter paper to be placed on the filter core.

[0017] 2. The present invention has multiple pressing structures installed on the side of the annular cylinder, each consisting of a pressing cylinder, a pressing plate, a pressing block, an inclined block, and a first elastic element. When the filtration bottle moves downward and presses the pressing structure, it drives the pressing structure to move downward and uses the pressing structure to press the filter core into the circular groove. At the same time, when water is poured into the filtration bottle, the pressing plate blocks part of the water flow at the contact point with the filter paper, reducing the probability of the filter paper getting damp, thereby reducing the probability of the filter paper being damaged when it is removed from the filter core and improving the accuracy of experimental data.

[0018] 3. This invention installs a pushing block on the lower surface of the lower pressure plate. The downward movement of the lower pressure plate causes the pushing block to contact the filter paper and push the filter paper to the center of the filter core. This ensures that the filter paper is accurately attached to the filter core, preventing the liquid in the filtration bottle from passing through the filter core and being drawn out by the vacuum pump in areas not covered by the filter paper. This improves the efficiency of the filter paper in collecting microorganisms from the liquid in the filtration bottle. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in this application will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of a microbial limit tester for food testing according to the present invention; Figure 2 This is an internal cross-sectional view of the limit analyzer body of a microbial limit analyzer for food testing according to the present invention. Figure 3 This is a cross-sectional view of the annular platform of a microbial limit tester for food testing according to the present invention. Figure 4 This is a schematic diagram of the assembly of filter paper, filter core, and annular plate in a microbial limit tester for food testing according to the present invention. Figure 5 This is a schematic diagram of the assembly of the support cylinder and the extrusion cylinder of a microbial limit tester for food testing according to the present invention. Figure 6 This is a cross-sectional view of the pressure relief cylinder of a microbial limit tester for food testing according to the present invention; Figure 7 This is a schematic diagram of the assembly of the pressure cylinder and pressure plate of a microbial limit tester for food testing according to the present invention.

[0021] In the diagram: 1. Limiting instrument body; 2. Drain pipe; 3. Filter bottle; 4. Annular plate; 5. Annular cylinder; 6. Annular platform; 7. Valve; 8. Vertical cylinder; 9. Inlet pipe; 10. Vacuum pump; 11. Through groove; 12. Vertical groove; 13. Annular groove; 14. Circular groove; 15. Supporting cylinder; 16. Supporting rod; 17. Sealing ring; 19. Pressure block; 20. Lower pressure cylinder; 21. Lower pressure plate; 22. Filter paper; 23. Filter core; 24. Squeezing rod; 25. Pressure relief cylinder; 26. Squeezing cylinder; 27. Connecting cylinder; 28. Support plug; 29. ​​Squeezing plug; 30. Second elastic element; 31. Balancing plug; 32. Inclined block; 33. First elastic element; 34. Pushing block. Detailed Implementation

[0022] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0024] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments. Please see Figures 1 to 7 The present invention provides a microbial limit tester for food testing, comprising a limit tester body 1, a vacuum pump 10 installed inside the limit tester body 1, a water inlet pipe 9 installed at the input end of the vacuum pump 10, a drain pipe 2 installed at the output end of the vacuum pump 10, a plurality of vertical cylinders 8 installed on the upper side of the annular surface of the water inlet pipe 9, a valve 7 installed inside the vertical cylinder 8, the valve 7 extending to the front of the limit tester body 1, a circular groove 14 opened on the upper surface of the annular platform 6, and a through groove 11 communicating with the vertical cylinder 8 opened at the bottom of the cylinder. When the limit tester is in use, the vacuum pump 10 is turned on first, and then the valve 7 is turned on. After the valve 7 is turned on, water flows from the circular groove 14 into the through groove 11, then flows through the through groove 11 into the vertical cylinder 8, then flows through the vertical cylinder 8 into the water inlet pipe 9, and finally is discharged from the drain pipe 2 through the vacuum pump 10.

[0025] A filter core 23 is placed inside the circular groove 14. Filter paper 22 is placed on the upper surface of the filter core 23. Multiple annularly arranged vertical grooves 12 are opened at the top edge of the circular groove 14. A support rod 16 is inserted into the vertical groove 12. The upper end of the support rod 16 contacts the filter core 23. A support cylinder 15 is sleeved on the lower end of the support rod 16. The support cylinder 15 is installed in the vertical groove 12. A support plug 28 is installed at one end of the support rod 16 in the through groove 11. The support plug 28 is slidably connected in the support cylinder 15. When the filter core 23 is placed in the circular groove 14, the filter core 23 uses its own weight to press the support rod 16, causing the support rod 16 and the support plug 28 to move into the support cylinder 15.

[0026] A connecting cylinder 27 is installed on the annular surface of the supporting cylinder 15. A squeezing cylinder 26 is installed on the side of the connecting cylinder 27 away from the supporting cylinder 15. A squeezing plug 29 is slidably connected inside the squeezing cylinder 26. A squeezing rod 24 is installed on the upper surface of the squeezing plug 29. After the supporting rod 16 moves the supporting plug 28, it squeezes the air inside the supporting cylinder 15. The air inside the supporting cylinder 15 is transported to the squeezing cylinder 26 through the connecting cylinder 27. Then, the air inside the squeezing cylinder 26 squeezes the squeezing plug 29 and causes the squeezing rod 24 installed on the upper surface of the squeezing plug 29 to move upward.

[0027] By installing a holding structure consisting of a holding rod 16, a holding cylinder 15 and a holding plug 28 in the vertical groove 12, the holding structure holds the filter core 23 placed in the circular groove 14, so that the filter core 23 cannot be completely submerged in the circular groove 14. This makes it easier to remove the filter paper 22 and the filter core 23 from the circular groove 14 after the microbial sampling is completed, reducing the probability of damage to the filter paper 22.

[0028] An annular groove 13 is provided at the edge of the upper surface of the annular platform 6. An annular cylinder 5 is slidably connected in the annular groove 13. An annular plate 4 is slidably connected in the annular groove 13. The extrusion rod 24 passes through the annular cylinder 5 and is connected to the annular plate 4. By installing an extrusion structure consisting of a connecting cylinder 27, an extrusion cylinder 26, an extrusion plug 29 and an extrusion rod 24 on the supporting structure, the supporting structure is used to extrude the extrusion structure. Then, the extrusion structure is used to push the annular plate 4 to move upward, thereby making room for the filter paper 22 to be placed on the filter core 23.

[0029] The annular plate 4 has multiple transverse grooves on its inner surface. A lower pressure cylinder 20 is installed in each groove. A lower pressure plate 21 is slidably connected inside the lower pressure cylinder 20. A first elastic element 33, which is a spring, is installed at one end of the lower pressure plate 21 inside the lower pressure cylinder 20. In its normal state, the end of the first elastic element 33 away from the lower pressure plate 21 is installed inside the lower pressure cylinder 20. The lower surface of the end of the lower pressure plate 21 away from the first elastic element 33 is in contact with the filter paper 22. A pressure block 19 is provided on the side of the lower pressure cylinder 20 away from the filter paper 22. An inclined block 32 is installed at one end of the pressure block 19 inside the lower pressure cylinder 20. The inclined block 32 is in slidable contact with the lower pressure plate 21. A sealing ring 17 is installed on the inner surface of the annular plate 4. A suction filtration bottle 3 is slidably connected inside the annular plate 4. The suction filtration bottle 3 is in slidable contact with the sealing ring 17. The end of the pressure block 19 away from the inclined block 32 passes through the lower pressure cylinder 20 and is in contact with the suction filtration bottle 3.

[0030] Multiple pressing structures, consisting of a lower pressing cylinder 20, a lower pressing plate 21, a pressure receiving block 19, an inclined block 32, and a first elastic element 33, are installed on the side of the annular cylinder 5. When the filtration bottle 3 is slidably connected to the annular plate 4 and moves downward, the filtration bottle 3 presses the pressure receiving block 19, causing the pressure receiving block 19 to move downward. The downward movement of the pressure receiving block 19 drives the inclined block 32 to squeeze the lower pressing plate 21, causing the lower pressing plate 21 to move outward from the lower pressing cylinder 20 and move to directly above the filter core 23 until the inclined block 32 moves and contacts the bottom of the lower pressing cylinder 20. At this time, the lower pressing plate 21 no longer moves outward from the lower pressing cylinder 20.

[0031] As the filtration flask 3 continues to move downwards, it presses down on the lower pressure cylinder 20 and uses its own weight to move the annular plate 4 downwards. The downward movement of the annular plate 4 causes the filter paper 22 mounted on the lower pressure plate 21 to come into contact with the filter paper 22, and the filter core 23 is pressed into the circular groove 14 through the filter paper 22. At this time, the filter core 23 is completely submerged in the circular groove 14. Meanwhile, the lower pressure plate 21 comes into contact with the filter paper 22. After water is poured into the filtration flask 3, the lower pressure plate 21 blocks part of the water flow from contacting the filter paper 22, reducing the probability of the filter paper 22 getting damp, thereby reducing the probability of the filter paper 22 being damaged when it is removed from the filter core 23 and improving the accuracy of the experimental data.

[0032] A pusher block 34 is installed on the lower surface of the lower pressure plate 21. The pusher block 34 slides in contact with the filter paper 22. When the lower pressure cylinder 20 of the lower pressure plate 21 moves outward, the lower pressure plate 21 drives the pusher block 34 to contact the filter paper 22 and pushes the filter paper 22 to the center of the filter core 23. This ensures that the filter paper 22 is accurately attached to the filter core 23, preventing the liquid in the filtration bottle 3 from passing through the filter core 23 and being drawn by the vacuum pump 10 in areas not covered by the filter paper 22. This improves the collection efficiency of the filter paper 22 for microorganisms in the liquid of the filtration bottle 3.

[0033] A pressure relief cylinder 25 is installed at the end of the connecting cylinder 27 away from the supporting cylinder 15. A balance plug 31 is slidably connected inside the pressure relief cylinder 25. A second elastic element 30, which is a spring, is installed on the side of the balance plug 31 away from the connecting cylinder 27. In its normal state, the end of the second elastic element 30 away from the balance plug 31 is installed inside the pressure relief cylinder 25. The function of the pressure relief cylinder 25 is that when the suction flask 3 uses its own weight to make the pressure cylinder 20 move downward, the annular plate 4 is squeezed by the annular plate 4. The pressure rod 24 squeezes the air in the pressure cylinder 26 through the pressure plug 29. At this time, the air in the pressure cylinder 26 enters the pressure relief cylinder 25 and pushes the balance plug 31 to move away from the connecting cylinder 27, and gradually compresses the second elastic element 30.

[0034] Specifically, in use, the filter core 23, annular plate 4, pressure block 19, lower pressure plate 21, and lower pressure cylinder 20, which need to come into contact with the liquid to be tested, are first sterilized. Then, the filter core 23 is placed in the circular groove 14. The filter core 23 uses its own weight to press the support rod 16, causing the support rod 16 to move the support plug 28 downward and squeeze the air in the support cylinder 15. The air in the support cylinder 15 enters the squeezing cylinder 26 through the connecting cylinder 27, and drives the squeezing plug 29 and squeezing rod 24 to move upward. The upward movement of the squeezing rod 24 causes the annular plate 4 to move upward, and the lower pressure cylinder 20 and lower pressure plate 21 are separated from the filter core 23. At this time, the filter paper 22 can be easily placed on the filter core 23 through the gap between the lower pressure plate 21 and the filter core 23.

[0035] Then, the filtration bottle 3 is inserted into the annular plate 4. During insertion, the filtration bottle 3 presses against the pressure block 19. The pressure block 19 causes the inclined block 32 to move downward and presses against the lower pressure plate 21, causing the lower pressure plate 21 to move outward from the lower pressure cylinder 20. This causes the pushing block 34 to move towards the filter core 23. After the pushing block 34 contacts the filter paper 22, it pushes the center of the filter paper 22 towards the center of the filter core 23. This prevents the area of ​​liquid in the filtration bottle 3 that has not been covered by the filter paper 22 from passing through the filter core 23 and being drawn by the vacuum pump 10, thereby improving the collection efficiency of the filter paper 22 for microorganisms in the liquid in the filtration bottle 3.

[0036] As the filtration flask 3 continues to move downwards, it presses down on the lower pressure cylinder 20 and uses its own weight to move the annular plate 4 downwards. When the annular plate 4 moves downwards, the lower pressure plate 21 contacts the filter paper 22 and presses the filter core 23 into the circular groove 14 through the filter paper 22. At this time, the filter core 23 is completely submerged in the circular groove 14. Simultaneously, the lower pressure plate 21 contacts the filter paper 22. After water is poured into the filtration flask 3, the lower pressure plate 21 blocks part of the water flow from contacting the filter paper 22, reducing the probability of the filter paper 22 getting damp, thereby reducing the probability of the filter paper 22 being damaged when it is removed from the filter core 23 and improving the accuracy of the experimental data.

[0037] When the filtration bottle 3 uses its own weight to move the lower pressure cylinder 20 and the annular plate 4 downwards, the annular plate 4 squeezes the squeezing rod 24. The squeezing rod 24 squeezes the air in the squeezing cylinder 26 through the squeezing plug 29. At this time, the air in the squeezing cylinder 26 enters the pressure relief cylinder 25 and pushes the balance plug 31 to move away from the connecting cylinder 27, and causes the second elastic element 30 to be gradually compressed. When the liquid in the filtration bottle 3 is completely extracted, the filtration bottle 3 is removed from the annular plate 4. The second elastic element 30 releases its rebound force to restore the positions of the squeezing rod 24 and the holding rod 16. At this time, the filter core 23 is lifted in the circular groove 14. Then the filter paper 22 and the filter core 23 can be taken out in sequence. When taking the filter paper 22, it is clamped from the dry part of the filter paper 22.

[0038] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A microbial limit detector for food testing, comprising a limit detector body, characterized in that, The limit meter body is equipped with a drainage component, and a valve is installed inside the drainage component. The valve extends to the front of the limit meter body. An annular platform is installed on the upper surface of the limit meter body. A circular groove is formed on the upper surface of the annular platform. A through groove communicating with the drainage component is formed at the bottom of the annular platform. Multiple vertical grooves arranged in annular pattern are formed at the top edge of the circular groove. A retaining member is inserted into the vertical groove. A filter core is placed in the circular groove. Filter paper is placed on the upper surface of the filter core and is in contact with the retaining member. An annular groove is formed at the upper edge of the annular platform. A sealing member is slidably connected in the annular groove. The retaining member is in contact with the sealing member. The lower end of the sealing member is in contact with the retaining member. The inner surface of the upper end of the sealing member is in contact with the filter paper. A suction filter bottle is slidably connected to the inner annular surface of the sealing member.

2. The microbial limit detector for food testing according to claim 1, characterized in that, The drainage component includes a vacuum pump, which is installed inside the limit instrument. The vacuum pump has an inlet pipe installed at its input end and a drain pipe installed at its output end. Multiple vertical cylinders are installed on the upper side of the annular surface of the inlet pipe. The end of each vertical cylinder away from the inlet pipe is connected to a through groove. The valve is installed inside the vertical cylinder.

3. A microbial limit detector for food testing according to claim 2, characterized in that, The supporting member includes a supporting rod, which is inserted into the vertical groove and contacts the filter core. A supporting cylinder is sleeved at the lower end of the supporting rod and installed in the vertical groove. A supporting plug is installed at one end of the supporting rod in the through groove. The supporting plug is slidably connected in the supporting cylinder. An extrusion member is installed on the annular surface of the supporting cylinder and contacts the sealing member.

4. A microbial limit detector for food testing according to claim 3, characterized in that, The extrusion component includes a connecting cylinder, which is mounted on the annular surface of the supporting cylinder. An extrusion cylinder is installed on the side of the connecting cylinder away from the supporting cylinder. An extrusion plug is slidably connected inside the extrusion cylinder. An extrusion rod is installed on the upper surface of the extrusion plug. The end of the extrusion rod away from the extrusion plug is connected to a sealing component.

5. A microbial limit detector for food testing according to claim 4, characterized in that, The sealing element includes an annular cylinder, which is installed in an annular groove. An annular plate is slidably connected in the annular groove. The extrusion rod passes through the annular cylinder and is connected to the annular plate. Multiple transverse grooves are formed on the inner surface of the annular plate. A pressing component is installed in the transverse groove. The lower surface of the pressing component is in contact with the filter paper. The suction filtration bottle is installed on the annular surface of the annular plate and is in slidable contact with the pressing component.

6. A microbial limit detector for food testing according to claim 5, characterized in that, The pressing component includes a pressing cylinder, which is installed in a transverse groove. A pressing plate is slidably connected inside the pressing cylinder. A first elastic element is installed at one end of the pressing plate inside the pressing cylinder. The end of the first elastic element away from the pressing plate is installed inside the pressing cylinder. The lower surface of the end of the pressing plate away from the first elastic element is in contact with the filter paper. A pressure-receiving component is installed on the side of the pressing cylinder away from the filter paper. The pressure-receiving component is in contact with the filtration bottle and the pressing plate.

7. A microbial limit detector for food testing according to claim 6, characterized in that, The pressure-receiving component includes a pressure-receiving block, which is installed inside the lower pressure cylinder. An inclined block is installed at one end of the pressure-receiving block inside the lower pressure cylinder. The inclined block slides in contact with the lower pressure plate. The end of the pressure-receiving block away from the inclined block passes through the lower pressure cylinder and contacts the suction filtration bottle.

8. A microbial limit detector for food testing according to claim 7, characterized in that, A pushing block is installed on the lower surface of the pressure plate, and the pushing block slides in contact with the filter paper.

9. A microbial limit detector for food testing according to claim 8, characterized in that, A pressure relief cylinder is installed at the end of the connecting cylinder away from the supporting cylinder. A balance plug is slidably connected inside the pressure relief cylinder. A second elastic element is installed on the side of the balance plug away from the connecting cylinder. The end of the second elastic element away from the balance plug is installed inside the pressure relief cylinder.

10. A microbial limit detector for food testing according to claim 9, characterized in that, A sealing ring is installed on the inner annular surface of the annular plate, and the filtration bottle slides in contact with the sealing ring.

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