A method for sterilizing soy sauce using liquid cross-flow membrane filtration technology
The sterilization of soy sauce through liquid cross-flow membrane filtration technology solves the problems of high equipment costs of existing methods and affecting the quality of soy sauce, and achieves efficient sterilization and maintaining the natural flavor of soy sauce.
Patent Information
- Application Number
- CN202411925578.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-25
- Publication Date
- 2025-04-01
AI Technical Summary
Existing soy sauce sterilization methods such as heating sterilization and continuous sterilization have problems such as high equipment costs and affecting the quality and flavor of soy sauce.
The liquid cross-flow membrane filtration technology is used to rinse the membrane through liquid cross-flow to prevent membrane blockage, improve filtration efficiency, and filter through hollow fiber membranes to maintain the natural flavor of soy sauce.
It has achieved efficient sterilization, with a sterilization rate of ≥99.9%, and maintained the natural sauce flavor of the soy sauce, fresh and refreshing taste, and complying with food safety standards.
Smart Images
Figure CN119732486A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of soy sauce production, and in particular to a method for sterilizing soy sauce by applying liquid cross-flow membrane filtration technology. Background Art
[0002] There are several main methods for sterilizing semi-finished soy sauce: 1. Heating sterilization: Put the semi-finished soy sauce into a sandwich pot and heat it to above 95°C, and keep the temperature for about 20-30 minutes, which can effectively kill most bacteria and microorganisms. This method is relatively simple to operate and has low equipment cost, but if the temperature is too high or the time is too long, it may affect the flavor and quality of the soy sauce and produce unpleasant burnt odors. 2. Continuous sterilization: Use equipment such as tubular heat exchange continuous heat sterilizers to allow the soy sauce to pass quickly through the pipeline and be heated to a certain temperature, and keep it for a short time to achieve the sterilization effect. This method can achieve continuous production with high efficiency, but the equipment investment and maintenance costs are also relatively high. Summary of the invention
[0003] The purpose of the present invention is to provide a method for sterilizing soy sauce by using liquid cross-flow membrane filtration technology, wherein the membrane is flushed by liquid cross-flow, thereby preventing the membrane from being blocked and effectively improving the filtration efficiency; the soy sauce filtered by the membrane retains the natural soy sauce aroma unique to the soy sauce, the filtrate is reddish brown, clear, transparent, free from burnt smell and other peculiar smell after high-temperature sterilization, and has a fresh taste.
[0004] The above technical objectives of the present invention are achieved through the following technical solutions: A method for sterilizing soy sauce using liquid cross-flow membrane filtration technology comprises the following steps: Step 1: pre-treatment of semi-finished soy sauce: filtering large particles of semi-finished soy sauce through a common filter membrane; Step 2: The liquid cross-flow membrane filtration system sterilizes the pre-treated semi-finished soy sauce; The liquid cross-flow membrane filtration system comprises a plurality of cross-flow membrane filtration components arranged in parallel, the cross-flow membrane filtration components comprising a shell, a plurality of hollow fiber membranes are arranged in the shell, and both ends of the hollow fiber membranes are fixed on isolation rubber heads; two isolation rubber heads are respectively fixed on both ends of the shell; the shell is provided with a filtrate outlet, a raw liquid outlet and a raw liquid inlet; The pretreated semi-finished soy sauce enters from the stock liquid inlet, and a portion of the semi-finished soy sauce flows out from the filtrate outlet after being filtered by the hollow fiber membrane. The finished soy sauce meets the requirements of the GB2717-2018 soy sauce food safety standard; a portion of the semi-finished soy sauce flows out from the stock liquid outlet after flushing the outer wall of the hollow fiber membrane to prevent the hollow fiber membrane from being blocked, and the reflux liquid after flushing can enter from the stock liquid inlet again; Step 3: Cleaning the liquid cross-flow membrane filtration system: After the filtration is completed or when the filtration speed does not meet the requirements, clean the liquid cross-flow membrane filtration system; Step 3-1: flush the system with cold water until the reflux liquid is colorless; Step 3-2: Use 0.8% to 0.9% NaOH solution to circulate and clean for 30 to 35 minutes, then soak for 10 to 12 hours; Step 3-3: Rinse with clean water until the pH value of the rinse water is neutral.
[0005] The present invention is further configured as follows: the pore size of the hollow fiber membrane is 0.18-0.25 μm.
[0006] The present invention is further configured as follows: the transmembrane pressure in step 2 is ≤0.2 Mpa.
[0007] The present invention is further configured as follows: the liquid cross-flow membrane filtration system further comprises a semi-finished soy sauce storage cylinder, which is arranged higher than other components of the system, so that the semi-finished soy sauce can flow out with a certain initial pressure and can also ensure smooth feeding. A liquid outlet pipe and a liquid return pipe are connected to the bottom of the semi-finished soy sauce storage cylinder; the liquid outlet pipe is connected to a liquid separation main pipe, and the liquid separation main pipe is connected to the raw liquid inlet of multiple cross-flow membrane filtration components through multiple first liquid-passing pipes; The liquid return pipe is connected to a liquid collecting main pipe, and the liquid collecting main pipe is connected to the raw liquid outlets of multiple cross-flow membrane filtration components through multiple second liquid passing pipes; The filtrate outlets of the multiple cross-flow membrane filtration components are connected to the finished soy sauce conveying pipe through the third liquid pipe.
[0008] The present invention is further configured as follows: a first pump is provided between the liquid outlet pipe and the liquid separation main pipe, and the first pump slightly increases the pressure of the semi-finished soy sauce entering the shell, and the pressure is controlled at 0.2 Mpa or less; The finished soy sauce delivery pipe is provided with a composite pump, which is located at the downstream side of the plurality of third liquid-passing pipes. The composite pump can both pump water and vacuum, thereby increasing the pressure difference inside and outside the membrane and improving the filtering efficiency.
[0009] The present invention is further configured as follows: the liquid cross-flow membrane filtration system further comprises a cleaning liquid cylinder, the upper portion of the cleaning liquid cylinder is connected to a tap water pipe, the lower portion of the cleaning liquid cylinder is connected to a cleaning liquid outlet pipe, and the cleaning liquid outlet pipe and the liquid outlet pipe are bypassed; The liquid outlet pipe is connected to a first liquid discharge pipe in a bypass manner, the finished soy sauce delivery pipe is connected to a second liquid discharge pipe in a bypass manner, and the downstream end of the second liquid discharge pipe is connected to the first liquid discharge pipe; The liquid return pipe is provided with a first transparent pipe, and the second liquid discharge pipe is provided with a second transparent pipe; The liquid outlet pipe is provided with a first valve, and the first valve is located between the first liquid discharge pipe and the cleaning liquid outlet pipe; The finished soy sauce delivery pipe is provided with a second valve, and the second liquid discharge pipe is located at the upstream side of the second valve; The first liquid discharge pipe is provided with a third valve, and the second liquid discharge pipe is provided with a fourth valve.
[0010] The present invention is further configured as follows: the steps of the cold water cleaning system in step 3 are: step 3-1-1: closing the first valve and the second valve, and opening the third valve and the fourth valve; Step 3-1-2: The water pipe supplies clean water to the cleaning liquid cylinder; Step 3-1-3: Clean water enters the liquid separation main pipe through the cleaning liquid outlet pipe, and the liquid separation main pipe transports the clean water to the shell through multiple first liquid pipes. A part of the clean water passes through the hollow fiber membrane and cleans the inside of the hollow fiber membrane and the finished soy sauce delivery pipe. The cleaned waste liquid is discharged from the second liquid discharge pipe to the first liquid discharge pipe; the other part of the clean water flushes the outer wall of the hollow fiber membrane and the inner wall of the shell. The flushed liquid is converged into the liquid collecting main pipe through multiple second liquid discharge pipes, and then passes through the return pipe, the semi-finished soy sauce storage cylinder, and the liquid outlet pipe in turn and is discharged from the first liquid discharge pipe, thereby flushing the return pipe, the semi-finished soy sauce storage cylinder, and the liquid outlet pipe.
[0011] The present invention is further configured as follows: the liquid collecting main pipe is connected to a first alkali solution return pipe in a bypass manner, and the first alkali solution return pipe and the second liquid discharge pipe are connected via a second alkali solution return pipe; The liquid return pipe is provided with a fifth valve, and the first alkali solution return pipe is located at the upstream side of the fifth valve; The first alkali solution reflux pipe is provided with a sixth valve, and the second alkali solution reflux pipe is located at the downstream side of the sixth valve; The second liquid discharge pipe is provided with a seventh valve, and the seventh valve is located between the first liquid discharge pipe and the second alkali solution reflux pipe.
[0012] The present invention is further configured as follows: the step of circulating cleaning with NaOH solution in step 3 is: Step 3-2-1: Prepare a NaOH solution with a mass concentration of 0.8% to 0.9% in the cleaning liquid cylinder; Step 3-2-2: Close the second valve, the fifth valve, and the seventh valve, and open the fourth valve and the sixth valve; Step 3-2-3: the NaOH solution enters the liquid separation main pipe through the cleaning liquid outlet pipe, and the liquid separation main pipe transports the NaOH solution to the shell through multiple first liquid pipes. A part of the NaOH solution passes through the hollow fiber membrane to clean the inside of the hollow fiber membrane and the finished soy sauce delivery pipe. The cleaned NaOH solution is discharged from the second liquid discharge pipe to the second alkali solution reflux pipe, and then refluxes into the cleaning liquid cylinder through the first alkali solution reflux pipe; another part of the NaOH solution flushes the outer wall of the hollow fiber membrane and the inner wall of the shell. The flushed NaOH solution converges to the liquid collecting main pipe through multiple second liquid pipes, and then refluxes into the cleaning liquid cylinder through the first alkali solution reflux pipe; Step 3-2-4: Follow the path of step 3-2-3 and cycle for 30 to 35 minutes; Step 3-2-5: Soak in NaOH solution for 10 to 12 hours.
[0013] Step 3-3: Rinse with clean water until the pH value of the rinse water is neutral. The clean water flushing path is the same as step 3-1.
[0014] The outstanding effects of the present invention are: Compared with the existing technology, the membrane is flushed by liquid cross-flow to prevent membrane clogging, which can effectively improve the soy sauce filtration efficiency; the soy sauce filtered through the membrane retains the natural soy sauce flavor unique to soy sauce, the filtrate is reddish brown, clear, transparent, without the burnt smell and other odors after high-temperature sterilization, and tastes fresh; the microbial indicators of the soy sauce after filtration: meet the requirements of the GB2717-2018 soy sauce food safety standard. The sterilization rate can reach ≥99.9%.
[0015] Membrane filtration is performed with a transmembrane pressure of less than 0.2 Mpa. Low-pressure filtration can effectively increase the service life of the membrane, and at the same time prevent the problem of incomplete sterilization caused by the deformation of high-pressure filtration microorganisms that are forced to pass through the membrane.
[0016] Through circulating flushing with alkali solution and long-term soaking, the microorganisms in the system can be effectively removed. Flushing after soaking can prevent the residual alkali solution and avoid chemical reactions between the alkali solution and certain components in the soy sauce, which may change the flavor of the soy sauce. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 A sterilization flow chart of an embodiment of the present invention; Figure 2 It is a structural schematic diagram of a liquid cross-flow membrane filtration system according to an embodiment of the present invention; Figure 3 It is a schematic structural diagram of a cross-flow membrane filtration assembly according to an embodiment of the present invention; Figure 4 for Figure 3 A partial enlarged view of A; Figure 5The flow path of soy sauce sterilization, the thick arrow in the figure is the flow direction of semi-finished soy sauce, and the thin arrow is the flow direction of finished soy sauce after filtration; Figure 6 It is the cleaning path of the clean water cleaning system; Figure 7 This is the cleaning path for the NaOH solution cleaning system.
[0018] Figure numerals: 10, cross-flow membrane filtration assembly; 11, semi-finished soy sauce storage cylinder; 12, liquid outlet pipe; 13, liquid return pipe; 14, liquid separation main pipe; 15, first liquid pipe; 16, liquid collection main pipe; 17, second liquid pipe; 18, third liquid pipe; 19, finished soy sauce delivery pipe; 20, first pump; 21, compound pump; 22, cleaning liquid cylinder; 23, tap water pipe; 24, cleaning liquid outlet pipe; 25, first liquid discharge pipe; 26, second liquid discharge pipe; 27, first transparent pipe; 28, second transparent pipe; 29, first alkali solution reflux pipe; 30, second alkali solution reflux pipe; 31, first valve; 32, second valve; 33, third valve; 34, fourth valve; 35, fifth valve; 36, sixth valve; 37, seventh valve; 101, shell; 102, hollow fiber membrane; 103, isolation rubber head; 1011, filtrate outlet; 1012, raw liquid outlet; 1013, raw liquid inlet. DETAILED DESCRIPTION
[0019] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.
[0020] The following references Figures 1 to 7 The embodiments of the present invention are described as follows: A liquid cross-flow membrane filtration system, such as Figures 2 to 4 As shown, it includes a plurality of cross-flow membrane filtration components 10 arranged in parallel, and the cross-flow membrane filtration components 10 include a shell 101, in which a plurality of hollow fiber membranes 102 are arranged, and both ends of the hollow fiber membranes 102 are fixed on isolation rubber heads 103; two isolation rubber heads 103 are respectively fixed on both ends of the shell 101; the shell 101 is provided with a filtrate outlet 1011, a raw liquid outlet 1012 and a raw liquid inlet 1013.
[0021] A method for sterilizing soy sauce using liquid cross-flow membrane filtration technology comprises the following steps: Step 1: pre-treatment of semi-finished soy sauce: filtering large particles of semi-finished soy sauce through a common filter membrane; Step 2: The liquid cross-flow membrane filtration system sterilizes the pre-treated semi-finished soy sauce; The pretreated semi-finished soy sauce enters from the stock solution inlet 1013, and a portion of the semi-finished soy sauce is filtered through the hollow fiber membrane 102 and then flows out from the filtrate outlet 1011. The finished soy sauce meets the requirements of the GB2717-2018 soy sauce food safety standard; a portion of the semi-finished soy sauce flushes the outer wall of the hollow fiber membrane 102 and then flows out from the stock solution outlet 1012 to prevent the hollow fiber membrane 102 from being blocked, and the flushed reflux liquid can enter from the stock solution inlet 1013 again; Step 3: Cleaning the liquid cross-flow membrane filtration system: After the filtration is completed or when the filtration speed does not meet the requirements, clean the liquid cross-flow membrane filtration system; Step 3-1: flush the system with cold water until the reflux liquid is colorless; Step 3-2: Use 0.8% to 0.9% NaOH solution to circulate and clean for 30 to 35 minutes, then soak for 10 to 12 hours; Step 3-3: Rinse with clean water until the pH value of the rinse water is neutral.
[0022] Preferably, the pore size of the hollow fiber membrane 102 is 0.18-0.25 μm.
[0023] Preferably, the transmembrane pressure in step 2 is ≤0.2 Mpa.
[0024] The liquid cross-flow membrane filtration system of the present embodiment further includes a semi-finished soy sauce storage cylinder 11, which is arranged higher than other components of the system, so that the semi-finished soy sauce can flow out with a certain initial pressure, and can also ensure smooth feeding. The bottom of the semi-finished soy sauce storage cylinder 11 is connected to a liquid outlet pipe 12 and a liquid return pipe 13; the liquid outlet pipe 12 is connected to a liquid separation main pipe 14, and the liquid separation main pipe 14 is connected to the raw liquid inlet 1013 of the multiple cross-flow membrane filtration components 10 through multiple first liquid pipes 15; The liquid return pipe 13 is connected to a liquid collecting main pipe 16, and the liquid collecting main pipe 16 is connected to the raw liquid outlets 1012 of the multiple cross-flow membrane filtration components 10 through multiple second liquid passing pipes 17; The filtrate outlets 1011 of the multiple cross-flow membrane filtration components 10 are connected to the finished soy sauce delivery pipe 19 through the third liquid pipe 18 .
[0025] A first pump 20 is provided between the liquid outlet pipe 12 and the liquid separation main pipe 14, and the first pump slightly increases the pressure of the semi-finished soy sauce entering the housing; The finished soy sauce delivery pipe 19 is provided with a compound pump 21, which is located at the downstream side of the plurality of third liquid pipes 18. The compound pump can both pump water and vacuum, thereby increasing the pressure difference between the inside and outside of the membrane and improving the filtration efficiency.
[0026] The specific steps for sterilizing soy sauce are as follows: Figure 3, Figure 4 , Figure 5 As shown: the processed semi-finished soy sauce is pumped to the semi-finished soy sauce storage cylinder, the semi-finished soy sauce in the semi-finished soy sauce storage cylinder enters the first pump through the liquid outlet pipe, and is pumped into the shell through the liquid separation main pipe and multiple first liquid pipes under the pressurization of the first pump. Then, a part of the semi-finished soy sauce in the shell passes through the hollow fiber membrane to become the sterilized finished soy sauce, and the finished soy sauce flows to the finished soy sauce delivery pipe at both ends through the central hole of the hollow fiber membrane and is delivered to the packaging workshop; while the other part of the semi-finished soy sauce flushes the outer wall of the hollow fiber membrane and then flows out from the raw liquid outlet 1012 to the liquid collecting main pipe, and finally flows back to the semi-finished soy sauce storage cylinder through the return liquid pipe for circulation filtration and flushing.
[0027] The microbial indicators of the filtered soy sauce products (after the product was diluted 10 times, the total colony count of ten products was tested according to the GB 4789.2-2022 method, and the results were: all <10; the coliform group was tested according to the second method of GB 4789.3-2016 for ten products, and the results were: all <10) are 100% in line with food safety requirements, with a sterilization rate of 99.99%. It is easy to operate and is controlled by a microcomputer throughout the process, and can be equipped with a fully automated production and filling line.
[0028] The liquid cross-flow membrane filtration system of this embodiment further includes a cleaning liquid cylinder 22, the upper portion of which is connected to a tap water pipe 23, the lower portion of which is connected to a cleaning liquid outlet pipe 24, and the cleaning liquid outlet pipe 24 is arranged in a bypass manner with the liquid outlet pipe 12; The liquid outlet pipe 12 is connected to a first liquid discharge pipe 25 in a bypass manner, and the finished soy sauce delivery pipe 19 is connected to a second liquid discharge pipe 26 in a bypass manner, and the downstream end of the second liquid discharge pipe 26 is connected to the first liquid discharge pipe 25; The return pipe 13 is provided with a first transparent pipe 27, and the second discharge pipe 26 is provided with a second transparent pipe 28; The liquid outlet pipe 12 is provided with a first valve 31, and the first valve 31 is located between the first liquid discharge pipe 25 and the cleaning liquid outlet pipe 24; The finished soy sauce delivery pipe 19 is provided with a second valve 32, and the second liquid discharge pipe 26 is located at the upstream side of the second valve 32; The first liquid discharge pipe 25 is provided with a third valve 33 , and the second liquid discharge pipe 26 is provided with a fourth valve 34 .
[0029] The specific steps of the cold water cleaning system are as follows: Figure 6 As shown, Step 3-1-1: Close the first valve 31 and the second valve 32, and open the third valve 33 and the fourth valve 34; Step 3-1-2: The water pipe 22 supplies clean water to the cleaning liquid cylinder 22; Step 3-1-3: Clean water enters the liquid separation main pipe 14 through the cleaning liquid outlet pipe 24, and the liquid separation main pipe 14 transports the clean water to the shell 101 through multiple first liquid pipes 15. A part of the clean water passes through the hollow fiber membrane 102 and cleans the inside of the hollow fiber membrane 102 and the finished soy sauce delivery pipe 19. The cleaned waste liquid is discharged from the second drainage pipe 26 to the first drainage pipe 25; the other part of the clean water flushes the outer wall of the hollow fiber membrane and the inner wall of the shell. The flushed liquid is converged into the liquid collecting main pipe 16 through multiple second liquid pipes 17, and then passes through the return pipe 13, the semi-finished soy sauce storage cylinder 11, and the liquid outlet pipe 12 in turn, and is discharged from the first drainage pipe 25, thereby flushing the return pipe 13, the semi-finished soy sauce storage cylinder 11, and the liquid outlet pipe 12.
[0030] The liquid collecting main pipe 16 of this embodiment is connected to a first alkali solution return pipe 29 in a bypass manner, and the first alkali solution return pipe 29 and the second liquid discharge pipe 26 are connected via a second alkali solution return pipe 30; The liquid return pipe 13 is provided with a fifth valve 35, and the first alkali solution return pipe 29 is located at the upstream side of the fifth valve 35; The first alkali solution reflux pipe 29 is provided with a sixth valve 36, and the second alkali solution reflux pipe 30 is located at the downstream side of the sixth valve 36; A seventh valve 37 is disposed on the second liquid discharge pipe 26 , and the seventh valve 37 is located between the first liquid discharge pipe 25 and the second alkali solution reflux pipe 30 .
[0031] The specific steps of NaOH solution circulation cleaning are as follows: Figure 7 As shown, Step 3-2-1: Prepare a NaOH solution with a mass concentration of 0.8% to 0.9% in the cleaning liquid cylinder 22; Step 3-2-2: Close the second valve 32, the fifth valve 35, and the seventh valve 37, and open the fourth valve 34 and the sixth valve 36; Step 3-2-3: NaOH solution enters the liquid separation main pipe 14 through the cleaning liquid outlet pipe 24, and the liquid separation main pipe 14 transports the NaOH solution to the shell 101 through multiple first liquid pipes 15. A part of the NaOH solution passes through the hollow fiber membrane 102 and cleans the inside of the hollow fiber membrane 102 and the finished soy sauce delivery pipe 19. The cleaned NaOH solution is discharged from the second liquid discharge pipe 26 to the second alkali solution reflux pipe 30, and then refluxes into the cleaning liquid cylinder 22 through the first alkali solution reflux pipe 29; another part of the NaOH solution flushes the outer wall of the hollow fiber membrane and the inner wall of the shell, and the flushed NaOH solution converges to the liquid collecting main pipe 16 through multiple second liquid pipes 17, and then refluxes into the cleaning liquid cylinder 22 through the first alkali solution reflux pipe 29; Step 3-2-4: Follow the path of step 3-2-3 and cycle for 30 to 35 minutes; Step 3-2-5: Soak in NaOH solution for 10 to 12 hours.
[0032] Step 3-3: Rinse with clean water until the pH value of the rinse water is neutral. The clean water flushing path is the same as step 3-1.
[0033] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications of the above assumptions should also be regarded as the scope of protection of the present invention.
Claims
1. A method for sterilizing soy sauce using liquid cross-flow membrane filtration technology, characterized in that: The following steps are involved: Step 1: pretreatment of semi-finished soy sauce; Step 2: The liquid cross-flow membrane filtration system sterilizes the pre-treated semi-finished soy sauce; The liquid cross-flow membrane filtration system comprises a plurality of cross-flow membrane filtration assemblies (10) arranged in parallel, the cross-flow membrane filtration assembly (10) comprising a shell (101), a plurality of hollow fiber membranes (102) being arranged in the shell (101), the two ends of the hollow fiber membranes (102) being fixed on an isolation rubber head (103); the two isolation rubber heads (103) being respectively fixed on the two ends of the shell (101); the shell (101) being provided with a filtrate outlet (1011), a raw liquid outlet (1012) and a raw liquid inlet (1013); The semi-finished soy sauce after pretreatment enters from the stock liquid inlet (1013), and a portion of the semi-finished soy sauce is filtered through the hollow fiber membrane (102) and then flows out from the filtrate outlet (1011), and the finished soy sauce meets the requirements of the GB2717-2018 soy sauce food safety standard; a portion of the semi-finished soy sauce flushes the outer wall of the hollow fiber membrane (102) and then flows out from the stock liquid outlet (1012) to prevent the hollow fiber membrane (102) from being blocked, and the reflux liquid after flushing can enter from the stock liquid inlet (1013) again; Step 3: Cleaning the liquid cross-flow membrane filtration system: After the filtration is completed or when the filtration speed does not meet the requirements, clean the liquid cross-flow membrane filtration system; Step 3-1: flush the system with cold water until the reflux liquid is colorless; Step 3-2: Use 0.8% to 0.9% NaOH solution to circulate and clean for 30 to 35 minutes, then soak for 10 to 12 hours; Step 3-3: Rinse with clean water until the pH value of the rinse water is neutral.
2. The method for sterilizing soy sauce by using liquid cross-flow membrane filtration technology according to claim 1, characterized in that: The pore size of the hollow fiber membrane (102) is 0.18-0.25 μm.
3. The method for sterilizing soy sauce by using liquid cross-flow membrane filtration technology according to claim 1, characterized in that: The transmembrane pressure in step 2 is ≤0.2 Mpa.
4. The method for sterilizing soy sauce by using liquid cross-flow membrane filtration technology according to claim 1, characterized in that: The liquid cross-flow membrane filtration system further comprises a semi-finished soy sauce storage cylinder (11), the bottom of which is connected to a liquid outlet pipe (12) and a liquid return pipe (13); the liquid outlet pipe (12) is connected to a liquid separation main pipe (14), and the liquid separation main pipe (14) is connected to the raw liquid inlet (1013) of the plurality of cross-flow membrane filtration assemblies (10) via a plurality of first liquid passage pipes (15); The liquid return pipe (13) is connected to a liquid collecting main pipe (16), and the liquid collecting main pipe (16) is connected to the raw liquid outlets (1012) of the plurality of cross-flow membrane filtration components (10) through a plurality of second liquid passing pipes (17); The filtrate outlets (1011) of the multiple cross-flow membrane filtration components (10) are connected to a finished soy sauce delivery pipe (19) via a third liquid-passing pipe (18).
5. The method for sterilizing soy sauce by using liquid cross-flow membrane filtration technology according to claim 4, characterized in that: A first pump (20) is provided between the liquid outlet pipe (12) and the liquid separation main pipe (14); The finished soy sauce delivery pipe (19) is provided with a compound pump (21), and the compound pump (21) is located at the downstream side of the plurality of third liquid passage pipes (18).
6. The method for sterilizing soy sauce by using liquid cross-flow membrane filtration technology according to claim 4, characterized in that: The liquid cross-flow membrane filtration system further comprises a cleaning liquid cylinder (22), the upper portion of the cleaning liquid cylinder (22) being connected to a tap water pipe (23), the lower portion of the cleaning liquid cylinder (22) being connected to a cleaning liquid outlet pipe (24), and the cleaning liquid outlet pipe (24) and the liquid outlet pipe (12) being arranged in a bypass manner; The liquid outlet pipe (12) is connected to a first liquid discharge pipe (25) in a bypass manner, the finished soy sauce delivery pipe (19) is connected to a second liquid discharge pipe (26) in a bypass manner, and the downstream end of the second liquid discharge pipe (26) is connected to the first liquid discharge pipe (25); The liquid return pipe (13) is provided with a first transparent tube (27), and the second liquid discharge pipe (26) is provided with a second transparent tube (28); The liquid outlet pipe (12) is provided with a first valve (31), and the first valve (31) is located between the first liquid discharge pipe (25) and the cleaning liquid outlet pipe (24); The finished soy sauce conveying pipe (19) is provided with a second valve (32), and the second liquid discharge pipe (26) is located on the upstream side of the second valve (32); The first liquid discharge pipe (25) is provided with a third valve (33), and the second liquid discharge pipe (26) is provided with a fourth valve (34).
7. The method for sterilizing soy sauce by using liquid cross-flow membrane filtration technology according to claim 6, characterized in that: The steps of the cold water cleaning system in step 3 are as follows: step 3-1-1: closing the first valve (31) and the second valve (32), and opening the third valve (33) and the fourth valve (34); Step 3-1-2: The water pipe (22) supplies clean water to the cleaning liquid cylinder (22); Step 3-1-3: clean water enters the liquid separation main pipe (14) through the cleaning liquid outlet pipe (24), and the liquid separation main pipe (14) transports the clean water into the shell (101) through a plurality of first liquid-passing pipes (15). A portion of the clean water passes through the hollow fiber membrane (102) and cleans the inside of the hollow fiber membrane (102) and the finished soy sauce conveying pipe (19). The waste liquid after cleaning is discharged from the second liquid discharge pipe (26) to the first liquid discharge pipe (25); another portion of the clean water flushes the outer wall of the hollow fiber membrane and the inner wall of the shell. The flushed liquid passes through a plurality of second liquid-passing pipes (17) and converges to the liquid collection main pipe (16), and then passes through the return liquid pipe (13), the semi-finished soy sauce storage cylinder (11), and the liquid outlet pipe (12) in sequence and is discharged from the first liquid discharge pipe (25), thereby flushing the return liquid pipe (13), the semi-finished soy sauce storage cylinder (11), and the liquid outlet pipe (12).
8. The method for sterilizing soy sauce by using liquid cross-flow membrane filtration technology according to claim 6, characterized in that: The liquid collecting main pipe (16) is connected to a first alkali liquid return pipe (29) in a bypass manner, and the first alkali liquid return pipe (29) and the second liquid discharge pipe (26) are connected via a second alkali liquid return pipe (30); The liquid return pipe (13) is provided with a fifth valve (35), and the first alkali solution return pipe (29) is located at the upstream side of the fifth valve (35); The first alkali solution reflux pipe (29) is provided with a sixth valve (36), and the second alkali solution reflux pipe (30) is located at the downstream side of the sixth valve (36); The second liquid discharge pipe (26) is provided with a seventh valve (37), and the seventh valve (37) is located between the first liquid discharge pipe (25) and the second alkali solution reflux pipe (30).
9. The method for sterilizing soy sauce by using liquid cross-flow membrane filtration technology according to claim 8, characterized in that: The steps of circulating cleaning with NaOH solution in step 3 are as follows: Step 3-2-1: Prepare a NaOH solution with a mass concentration of 0.8% to 0.9% in the cleaning liquid cylinder (22); Step 3-2-2: Close the second valve (32), the fifth valve (35), and the seventh valve (37), and open the fourth valve (34) and the sixth valve (36); Step 3-2-3: the NaOH solution enters the liquid separation main pipe (14) through the cleaning liquid outlet pipe (24), and the liquid separation main pipe (14) transports the NaOH solution to the shell (101) through a plurality of first liquid passing pipes (15). A portion of the NaOH solution passes through the hollow fiber membrane (102) to clean the inside of the hollow fiber membrane (102) and the finished soy sauce conveying pipe (19). The cleaned NaOH solution is discharged from the second liquid discharge pipe (26) to the second alkali solution reflux pipe (30), and then refluxes into the cleaning liquid cylinder (22) through the first alkali solution reflux pipe (29); another portion of the NaOH solution flushes the outer wall of the hollow fiber membrane and the inner wall of the shell. The flushed NaOH solution flows into the liquid collecting main pipe (16) through a plurality of second liquid passing pipes (17), and then refluxes into the cleaning liquid cylinder (22) through the first alkali solution reflux pipe (29); Step 3-2-4: Follow the path of step 3-2-3 and cycle for 30 to 35 minutes; Step 3-2-5: Soak in NaOH solution for 10 to 12 hours.