Device and test method for verifying bacterial interception performance of hydrophobic membrane

Abstract

The invention relates to a device for verifying the bacterial interception performance of a hydrophobic membrane and a testing method, the device comprises a charging barrel and a plurality of filtering branches which are connected in parallel and connected with the charging barrel, each filtering branch comprises a pump, a membrane filter and an analysis filter which are sequentially connected in series, and each filtering branch and the charging barrel form a circulating loop. According to the test method, the hydrophobic membrane is taken as an experimental subject, and a Tween 80 solution is taken as a carrier of challenging bacteria, so that the bacterial interception capability of the hydrophobic membrane is confirmed. Compared with the prior art, the degerming and filtering process verification device provided by the invention is reasonable and compact in structure and convenient to use, a plurality of experimental groups and a control group are simultaneously unfolded through the installation of a plurality of parallel assemblies, and the repeatability and the accuracy of a test result are ensured; the Tween 80 solution is used as a carrier of challenging bacteria, so that the shape of the hydrophobic membrane is not influenced, the bacteria are not killed, and the bacterial interception capability of the hydrophobic membrane can be rapidly and accurately determined.

Description

Technical Field

[0001] The invention relates to a bacteria retention test device, in particular to a device and a test method for verifying the bacteria retention performance of a hydrophobic membrane. Background Art

[0002] The test method for verifying the bacterial retention performance of the hydrophobic membrane usually includes the following steps: first, the hydrophobic membrane is subjected to an organic solvent process cycle to simulate actual production conditions, and then rinsed with water to remove the organic solvent residue on the hydrophobic membrane; after rinsing, a soy casein broth (SLB) aqueous solution is usually used as a carrier of the challenge bacteria to test the bacterial retention capacity of the hydrophobic membrane to be no less than 1.0×10 7 CFU / cm 2 Challenge level. However, due to the characteristics of the hydrophobic membrane, the SLB aqueous solution is not an ideal carrier, and organic solvents often kill bacteria, which will affect the accuracy of the test. In addition, after the organic solvent circulation treatment, the step of washing the organic solvent residue on the hydrophobic membrane with water will cause the flow rate of the entire test system to become very slow, and sometimes even hinder the addition of challenge bacteria, thereby increasing the difficulty of the test.

[0003] Therefore, there is an urgent need to develop a new carrier liquid, test device, and test method that can keep the properties of the hydrophobic membrane intact while not killing the bacteria, ensuring that the challenge bacteria can be smoothly added to the test system to improve the reliability and accuracy of the test. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide a device and a testing method for verifying the bacterial retention performance of a hydrophobic membrane. The device and the testing method can quickly and accurately determine the bacterial retention capacity of the hydrophobic membrane.

[0005] The conceptual process of the present application is as follows: the present invention adopts a recyclable sterilization filtration process verification device, takes a hydrophobic membrane as an experimental object, and a Tween 80 solution as a carrier of challenge bacteria to confirm the bacterial retention capacity of the hydrophobic membrane. The Tween 80 solution of appropriate concentration provided by the present invention can keep the shape of the hydrophobic membrane intact and will not kill the bacteria.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] In one aspect, the present invention provides a device for verifying the bacterial retention performance of a hydrophobic membrane, comprising:

[0008] The first barrel is used for supplying the actual liquid or the simulated liquid;

[0009] The second barrel is used for supplying bacterial liquid;

[0010] A plurality of filter branches connected in parallel and connected to the first barrel and the second barrel, wherein the filter branches include a pump, a membrane filter, and an analysis filter connected in series in sequence, and each of the filter branches forms a circulating loop with the first barrel;

[0011] A pump, used to provide power for the feed liquid and bacterial liquid to flow in the device;

[0012] Membrane filters, at least 4, connected in parallel, for trapping bacteria;

[0013] The analytical filters, the number of which is the same as that of the membrane filters, are used to retain bacteria not retained in the filtrate of the membrane filters.

[0014] Furthermore, the membrane filter includes a test filter and a control filter, the test filter uses a hydrophobic membrane with a specification of 0.22 μm, and the control filter uses a hydrophobic membrane with a specification of 0.45 μm).

[0015] Preferably, there are at least three test filters.

[0016] Preferably, the hydrophobic membrane is a polytetrafluoroethylene hydrophobic membrane.

[0017] Furthermore, a pump is installed on one side of each filter branch close to the barrel.

[0018] Furthermore, pressure gauges are installed at both the input and output ends of the membrane filter.

[0019] On the other hand, the present invention also provides a test method for verifying the bacterial retention performance of a hydrophobic membrane, comprising the following steps:

[0020] S1. Prepare Tween 80 solution and confirm that Tween 80 solution has no killing effect on bacteria;

[0021] S2, first add the actual liquid into the first barrel, filter the actual liquid within the preset time (customer process temperature), then replace the actual liquid in the first barrel with the Tween 80 solution configured in S1, rinse the verification device with the Tween 80 solution, and after rinsing, add the challenge bacterial solution into the second barrel. The Tween 80 solution is used as a carrier liquid and flows through the membrane filter and analysis filter of the verification device together with the bacterial solution. When the preset challenge level is added, that is, not less than 1.0×10 7 CFU / cm 2 After counting the number of bacteria, take out the analysis membrane on the analysis filter and place it in an incubator at 30℃±2℃ for 24h. If there is no defective Brevundimonas colony or miscellaneous bacteria colony on the analysis membrane, it is considered that the bacterial retention test has passed;

[0022] S3. Dry the hydrophobic membrane soaked in Tween 80 solution, and use an electron microscope to confirm that the properties of the hydrophobic membrane are not affected by the Tween 80 solution.

[0023] Preferably, in S1, the concentration of the Tween 80 solution is 1 wt %.

[0024] Preferably, in S2, the preset time is the time required for the customer's process.

[0025] Preferably, in S2, the challenge bacteria is Brevundimonas defective ATCC19146, which can be purchased commercially.

[0026] Preferably, in S3, the drying temperature is 60°C.

[0027] Furthermore, the test filter has a retention greater than or equal to 1.0×10 7 CFU / cm 2 The challenge bacteria and the fact that the analytical filter did not retain the challenge bacteria demonstrated that the hydrophobic membrane had excellent bacterial retention performance.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) The recyclable sterilization filtration process verification device provided by the present invention has a reasonable and compact structure and is easy to use. The installation of multiple parallel components enables the simultaneous development of multiple experimental groups and control groups, ensuring the repeatability and accuracy of the test results.

[0030] (2) The test method for verifying the bacterial retention performance of the hydrophobic membrane provided by the present invention uses Tween 80 solution as a carrier of the challenge bacteria. Without affecting the activity of the bacteria, there will be no "break" in the entire bacterial addition process, which can ensure the smooth addition of bacteria and ensure that the bacterial retention challenge level of the hydrophobic membrane is not less than 1.0×10 7 CFU / cm 2 . BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic diagram of a device for verifying the bacteria retention performance of a hydrophobic membrane provided in Example 1 of the present invention;

[0032] Figure 2 Photographs of initial survival culture results;

[0033] Figure 3 This is a photo of the survival culture results after 1 hour;

[0034] Figure 4 This is an electron microscope photo of the hydrophobic membrane;

[0035] Figure 5 This is an electron microscope photo of a solution containing Tween 80;

[0036] Figure 6This is an electron microscope photograph of the hydrophobic membrane after washing with Tween 80 solution.

[0037] 1 - first cartridge, 2 - second cartridge, 3 - pump, 4 - pressure gauge, 5 - first test filter, 6 - second test filter, 7 - third test filter, 8 - control filter, 9 - analysis filter. DETAILED DESCRIPTION

[0038] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. Any features such as preparation means, materials, structures or composition ratios not clearly described in this technical solution are regarded as common technical features disclosed in the prior art.

[0039] The test hydrophobic membrane used in the following examples is a 0.22 μm polytetrafluoroethylene hydrophobic membrane produced by Yiming Company, with the article number FN02D47; the analytical hydrophobic membrane used is a 0.45 μm polytetrafluoroethylene hydrophobic membrane produced by Yiming Company, with the article number FN04D47. The effective filtration area of ​​the test membrane filter is 13.8 cm 2 .

[0040] Tween 80 stock solution is commercially available, and 0.5 wt % Tween 80 solution, 1.0 wt % Tween 80 solution, and 1.5 wt % Tween 80 solution were prepared as test solutions.

[0041] The commercially purchased Brevundimonas difficile (ATCC 19146) challenge suspension used in this experiment was prepared by direct culture method. The challenge bacteria obtained by this method have high vitality and the bacteria are in a dispersed state, which is suitable for bacterial challenge testing. Any Brevundimonas difficile (ATCC 19146) challenge suspension should be monodisperse. The batch number of Brevundimonas difficile used in the example is FA1104. The preparation method of the challenge bacterial solution is: 1. Inoculate the seed plate into 10mL sterile trypticase peptone broth medium (TSB) and culture at 30±2℃ for 24h. 2. Take 2mL of the stirred broth culture and transfer it to 1L sterile salt lactose broth medium (SLB), stir to fully mix the inoculum, and culture at 30±2℃ for 24h. Check the concentration of the inoculum (the expected value is 10 7 ~10 8 CFU / mL).

[0042] The experimental challenge was to add 10 ml of bacterial solution with a bacterial concentration of 1.0×10 8 CFU / ml, that is, the total challenge bacteria is 1.0×10 9 CFU, challenge level = total challenge bacteria / effective filtration area = 1.0×10 9 / 4×13.8=1.8×10 7 CFU / cm 2 , meet the challenge level.

[0043] Example 1

[0044] like Figure 1 As shown, this embodiment provides a device for verifying the bacterial retention performance of a hydrophobic membrane, comprising: a first barrel 1, a second barrel 2, and a plurality of filter branches connected in parallel to the first barrel 1 and the second barrel 2, wherein the filter branches comprise a pump 3, a membrane filter, and an analysis filter 9 connected in series in sequence, and each of the filter branches forms a circulating loop with the first barrel 1.

[0045] In this embodiment, the first barrel 1 is used for conveying the actual feed liquid or Tween 80 solution, and the second barrel 2 is used for conveying the bacterial liquid.

[0046] In this embodiment, a pump 3 is installed on the side of each filtration branch close to the barrel for pumping the liquid in the two barrels and providing power for the liquid to flow in the verification device. A pump 3 is provided above the second barrel 2 for pumping the bacterial liquid in the second barrel 2.

[0047] In this embodiment, an exhaust port is provided above the second barrel 2 and at the leftmost end of each filter branch. Figure 1 (not shown) for exhausting air from the system.

[0048] In this embodiment, there are a total of 4 membrane filters connected in parallel for intercepting challenge bacteria, the membrane filters include 3 test filters and 1 control filter, the test filters include a first test filter 5, a second test filter 6, and a third test filter 7, the test filters use a polytetrafluoroethylene hydrophobic membrane with a specification of 0.22μm, and the control filter 8 uses a polytetrafluoroethylene hydrophobic membrane with a specification of 0.45μm.

[0049] In this embodiment, there are four analysis filters 9 installed behind the membrane filter to collect the challenge bacteria that may not be present in the filtrate of the membrane filter.

[0050] In this embodiment, a pressure gauge 4 is installed at each of the input end and the output end of the membrane filter.

[0051] In this embodiment, the first test filter 5, the second test filter 6, and the third test filter 7 are designed as an experimental group, and a polytetrafluoroethylene hydrophobic membrane of 0.22 μm is selected. An appropriate amount of Brevundimonas diminuta (ATCC 19146) challenge suspension is added to the challenge system and filtered through a 0.22 μm filter membrane to make the final challenge level not less than 1.0×10 7 CFU / cm 2The control filter 8 is designed as the control group, and a polytetrafluoroethylene hydrophobic membrane with a specification of 0.45 μm is selected. After all the filtrates of the four groups flow through the analytical filter membrane of the analytical filter 9, the analytical filter membrane is placed on a solid culture medium for culture, and the number of colonies is recorded. The analytical filter membrane of the experimental group should be sterile, and the analytical filter membrane of the control group should detect shortwave monocytogenes, which can prove that the bacterial retention performance of the verified hydrophobic membrane meets the requirements.

[0052] The working principle is: Brevundimonas diminuta (approximately 0.3-0.4 microns in diameter, 0.6-1.0 microns in length, must be single, dispersed cells) is the standard challenge microorganism for bacterial retention tests in sterilization filtration validation. The filter membrane used in the microbial retention test must be exactly the same as the filter material used in actual production, and should include multiple batches (usually three batches). A filter membrane with a pore size of 0.45 microns should be selected as the positive control for each test in the microbial retention test. The size of the challenge microorganism needs to be able to penetrate the 0.45-micron filter membrane to prove that it has been cultured to the appropriate size and concentration. Three different batches of 0.22-micron (or 0.2-micron) test filters and 0.45-micron control filters must be challenged online in parallel in a test system. The bacterial challenge level should not be lower than 10 as specified in ASTM F838-05 and the Pharmacopoeia of the People's Republic of China. 7 CFU / cm 2 , sterile filtrate should be obtained downstream of the test filter, that is, no defective Brevundimonas colonies or foreign bacterial colonies are generated on the analysis membrane.

[0053] Example 2

[0054] Based on the verification device of Example 1, this embodiment provides a test method for verifying the bacteria retention performance of a hydrophobic membrane, comprising the following steps:

[0055] S1. Prepare a Tween 80 solution with a concentration of (1wt%), and mix (4.5)mL of Tween 80 solution and (0.5)mL of bacterial suspension using a vortex oscillator. Take 4.5mL of sterilized 0.9% sodium chloride solution as a positive control, inoculate 0.5mL of the challenge bacteria cultured, and mix using a vortex oscillator. Count the bacterial concentration of the mixed solution: dilute the mixed solution 10 times in volume to 10 with 0.1% peptone aqueous solution. -5 From 10 -3 Up to 10 -5Take 0.1mL of the diluted solution and spread it on the TSA plate for plate counting. Prepare at least 2 plates for each dilution level. Incubate the plates at 30±2℃ for at least 3 days. Select plates with colony counts between 30 and 300 for counting, and calculate the bacterial concentration. Compare the initial bacterial concentration and the bacterial concentration after 1 hour to obtain the survival characteristics of bacteria in Tween 80 solution. The results show that Tween 80 solution has no killing effect on bacteria. The survival results are as follows: Figure 2 , Figure 3 shown.

[0056] S2. After confirming that the Tween 80 solution has no killing effect on bacteria, first add (anhydrous ethanol) to the first barrel 1, perform an actual production cycle (1h) in the verification device, then replace the (anhydrous ethanol) in the first barrel 1 with the Tween 80 solution configured in S1, rinse the verification device with the Tween 80 solution, and after rinsing, add the challenge bacteria solution (Brevetomonas defective) to the second barrel 2, open the valve above the second barrel 2, and under the action of the pump 3, the Tween 80 solution as the carrier liquid flows through the first test filter 5, the second test filter 6, the third test filter 7, the control filter 8 and the analysis filter 9, and the specific flow rate is as shown in the following table.

[0057] Table 1 Test filter 5 membrane challenge cycle parameters

[0058]

[0059] Table 2 Test filter 6 membrane challenge cycle parameters

[0060]

[0061] Table 3 Test filter 7 membrane challenge cycle parameters

[0062]

[0063] Table 4 Control filter 8 membrane challenge cycle parameters

[0064]

[0065] The bacterial concentration of the challenge solution was 1.2×10 8 CFU / ml, the volume of bacteria added was 10ml, the time of bacteria addition was 40min, and the total amount of challenge bacteria in the four groups of membranes was 1.2×10 9 CFU. The total challenge bacteria count of the test film is 3.0×10 8 CFU, effective filtration area is 13.8cm 2 , the diaphragm challenge level is 2.2×10 7 CFU / cm 2 .

[0066] S3. Dry the hydrophobic membrane soaked in Tween 80 solution (60°C) and observe it using a Phenom electron microscope. Figure 4 , Figure 5 , Figure 6 As shown, the properties of the hydrophobic membrane were not affected by Tween 80 solution.

[0067] Comparative Example 1

[0068] Based on the verification device of Example 1, this embodiment provides a test method for verifying the bacteria retention performance of a hydrophobic membrane, comprising the following steps:

[0069] S1. Prepare a (0.5%) concentration of Tween 80 solution, and mix (4.5) mL of Tween 80 solution and (0.5) mL of bacterial suspension using a vortex oscillator. Take 4.5 mL of sterilized 0.9% sodium chloride solution as a positive control, inoculate 0.5 mL of the cultured challenge bacteria, and mix using a vortex oscillator. Count the bacterial concentration of the mixed solution: dilute the mixed solution 10 times in volume to 10 with 0.1% peptone aqueous solution. -5 From 10 -3 Up to 10 -5 0.1 mL of the diluted solution was taken from each solution and spread on a TSA plate for plate counting. At least 2 plates were prepared for each dilution level. The plates were cultured at 30±2℃ for at least 3 days. Plates with colony counts between 30 and 300 were selected for counting, and the bacterial concentration was calculated. The initial bacterial concentration and the bacterial concentration after 1 hour were compared to obtain the survival characteristics of bacteria in Tween 80 solution. The results showed that Tween 80 solution had no killing effect on bacteria.

[0070] S2. After confirming that the Tween 80 solution has no killing effect on bacteria, first add (anhydrous ethanol) to the first barrel 1, perform an actual production cycle (1h) in the verification device, then replace the (anhydrous ethanol) in the first barrel 1 with the Tween 80 solution configured in S1, rinse the verification device with the Tween 80 solution, and after rinsing, add the challenge bacteria solution (Brevetomonas defective) to the second barrel 2, open the valve above the second barrel 2, and under the action of the pump 3, the Tween 80 solution as the carrier liquid flows through the first test filter 5, the second test filter 6, the third test filter 7, the control filter 8 and the analysis filter 9, and the specific flow rate is as shown in the following table.

[0071] Table 5 Test filter 5 membrane challenge cycle parameters

[0072]

[0073] Table 6 Test filter 6 membrane challenge cycle parameters

[0074]

[0075] Table 7 Test filter 7 membrane challenge cycle parameters

[0076]

[0077] Table 8 Comparative filter 8 membrane challenge cycle parameters

[0078]

[0079] The bacterial concentration of the challenge solution was 1.1×10 8 CFU / ml, the volume of bacteria added was 10ml, the time of bacteria addition was 40min, and the total challenge bacteria in the four groups of membranes was 1.1×10 9 CFU. The total number of challenge bacteria in the test film is 2.8×10 8 CFU, effective filtration area is 13.8cm 2 , the diaphragm challenge level is 2.0×10 7 CFU / cm 2 .

[0080] Disadvantages: When Tween 80 solution of this concentration is used as carrier liquid, the flow rate does not drop much at the beginning, because the time required for adding bacteria is long. As time goes by, the flow rate slowly approaches 0, and the bacteria cannot pass through the hydrophobic membrane, and the challenge level cannot be reached. Therefore, Tween 80 solution of this solubility is not an ideal concentration.

[0081] Comparative Example 2

[0082] Based on the verification device of Example 1, this embodiment provides a test method for verifying the bacteria retention performance of a hydrophobic membrane, comprising the following steps:

[0083] S1. Prepare a (1.5wt%) Tween 80 solution, and mix (4.5)mL of Tween 80 solution and (0.5)mL of bacterial suspension using a vortex oscillator. Take 4.5mL of sterilized 0.9wt% sodium chloride solution as a positive control, inoculate 0.5mL of the challenge bacteria cultured, and mix using a vortex oscillator. Count the bacterial concentration of the mixed solution: dilute the mixed solution 10 times in volume to 10 with 0.1% peptone aqueous solution. -5 From 10 -3 Up to 10 -5 0.1 mL of the diluted solution was taken from each solution and spread on a TSA plate for plate counting. At least 2 plates were prepared for each dilution level. The plates were cultured at 30±2℃ for at least 3 days. Plates with colony counts between 30 and 300 were selected for counting, and the bacterial concentration was calculated. The initial bacterial concentration and the bacterial concentration after 1 hour were compared to obtain the survival characteristics of bacteria in Tween 80 solution. The results showed that Tween 80 solution had no killing effect on bacteria.

[0084] S2. After confirming that the Tween 80 solution has no killing effect on bacteria, first add (anhydrous ethanol) to the first barrel 1, perform an actual production cycle (1h) in the verification device, then replace the (anhydrous ethanol) in the first barrel 1 with the Tween 80 solution configured in S1, rinse the verification device with the Tween 80 solution, and after rinsing, add the challenge bacteria solution (Brevetomonas defective) to the second barrel 2, open the valve above the second barrel 2, and under the action of the pump 3, the Tween 80 solution as the carrier liquid flows through the first test filter 5, the second test filter 6, the third test filter 7, the control filter 8 and the analysis filter 9, and the specific flow rate is as shown in the following table.

[0085] Table 5′ Test filter 5 membrane challenge cycle parameters

[0086]

[0087] Table 6′ Test filter 6 membrane challenge cycle parameters

[0088]

[0089] Table 7′ Test filter 7 membrane challenge cycle parameters

[0090]

[0091] Table 8' Control Filter 8 Membrane Challenge Cycle Parameters

[0092]

[0093] The bacterial concentration of the challenge solution was 1.3×10 8 CFU / ml, the volume of bacteria added was 10ml, the time of bacteria addition was 40min, and the total amount of challenge bacteria in the four groups of membranes was 1.3×10 9 CFU. The total number of challenge bacteria in the test film is 3.3×10 8 CFU, effective filtration area is 13.8cm 2 , the diaphragm challenge level is 2.4×10 7 CFU / cm 2 .

[0094] Disadvantages: Although the flow rate did not decrease much when using this concentration of Tween 80 solution as the carrier liquid, typical bacteria grew on the membrane after 24 hours of culture and analysis, and the properties of the membrane did not change. However, it may be that due to the high content of Tween 80, the bacteria "slipped" along with the Tween 80, resulting in the growth of bacteria on the membrane; it is also possible that the membrane could not stop the bacteria and the experimental purpose could not be achieved, so this is not an ideal concentration.

[0095] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A device for verifying the bacterial retention performance of a hydrophobic membrane, characterized in that: include: The first barrel (1) is used for supplying actual liquid or simulated liquid; The second barrel (2) is used for supplying bacterial liquid; A plurality of filter branches connected in parallel and respectively connected to the first barrel (1) and the second barrel (2), the filter branches comprising a pump (3), a membrane filter, and an analysis filter (9) connected in series in sequence, each of the filter branches forming a circulating loop with the first barrel (1); The pump (3) is used to provide power for the feed liquid and bacterial liquid to flow in the device; The membrane filter is used to intercept bacteria; The number of the analytical filters (9) is the same as that of the membrane filters, and they are used to retain bacteria that are not retained in the filtrate of the membrane filter, so as to verify the bacteria retention performance of the hydrophobic membrane.

2. A device for verifying the bacteria retention performance of a hydrophobic membrane according to claim 1, characterized in that: The membrane filter includes a test filter and a control filter, and each filter branch is provided with a test filter or a control filter; The test filter uses a hydrophobic membrane with a specification of 0.22 μm; The control filter uses a hydrophobic membrane with a specification of 0.45 μm.

3. A device for verifying the bacteria retention performance of a hydrophobic membrane according to claim 2, characterized in that: There are at least four filtering branches and at least three test filters.

4. A device for verifying the bacteria retention performance of a hydrophobic membrane according to claim 2, characterized in that: The hydrophobic membrane is a polytetrafluoroethylene hydrophobic membrane.

5. A device for verifying the bacteria retention performance of a hydrophobic membrane according to claim 1, characterized in that: A pump (3) is installed on the side of each filter branch close to the barrel.

6. A device for verifying the bacteria retention performance of a hydrophobic membrane according to claim 1, characterized in that: Pressure gauges (4) are installed at both the input end and the output end of the membrane filter.

7. A test method for verifying the bacterial retention performance of a hydrophobic membrane, characterized in that: The device for verifying the bacterial retention performance of the hydrophobic membrane according to any one of claims 1 to 6 is used to implement the test method, and the test method comprises the following steps: S1. Prepare Tween 80 solution and confirm that Tween 80 solution has no killing effect on bacteria; S2, firstly add the actual liquid into the first barrel (1), filter the actual liquid within a preset time, then replace the actual liquid in the first barrel (1) with the Tween 80 solution configured in S1, after rinsing, add the challenge bacterial solution into the second barrel (2), the Tween 80 solution as the carrier liquid and the bacterial solution flow through the membrane filter and the analysis filter (9) of the verification device in sequence, when the preset challenge level is added, i.e., not less than 1.0×10 7 CFU / cm 2 After measuring the bacterial count, take out the analytical membrane on the analytical filter and place it in an incubator at 30℃±2 for 24h. If there is no defective Brevundimonas colony or miscellaneous bacteria colony on the analytical membrane, it is considered that the bacterial retention test has passed; S3. Dry the hydrophobic membrane soaked in Tween 80 solution to confirm that the properties of the hydrophobic membrane are not affected by the Tween 80 solution.

8. A test method for verifying the bacterial retention performance of a hydrophobic membrane according to claim 7, characterized in that: In S1, the concentration of the Tween 80 solution is 1.0 wt%.

9. A test method for verifying the bacterial retention performance of a hydrophobic membrane according to claim 7, characterized in that: In S2, the challenge bacteria is Brevundimonas diminuta, and the challenge level of the challenge bacteria is not less than 1.0×10 7 CFU / cm 2 .

10. A test method for verifying the bacterial retention performance of a hydrophobic membrane according to claim 7, characterized in that: The test filter retention is greater than or equal to 1.0×10 7 CFU / cm 2 The challenge bacteria and the fact that the analysis filter (9) did not retain the challenge bacteria prove that the bacterial retention performance of the hydrophobic membrane meets the requirements.

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