A propagation system for dairy starter cultures

Abstract

The application relates to the technical field of dairy product processing, and discloses an expansion culture system for dairy product strains, a sterile online mixing device and an expansion culture tank for strain expansion culture; a feeding line is arranged between the sterile online mixing device and the expansion culture tank, an expansion culture tank feeding valve is installed on the feeding line; a heat preservation layer is arranged on the periphery of the expansion culture tank, and an ice water inlet valve is arranged on the heat preservation layer to cool the expansion culture stock solution in the expansion culture tank; a discharging line is arranged at the other end of the expansion culture tank, and a material quantitative discharging valve and a flow controller are arranged on the discharging line. The application has the effects of reducing strain waste in the production process and reducing production cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of dairy product processing, and in particular to an expansion system for dairy product strains. BACKGROUND

[0002] Fermentation tanks are one of the main equipment for dairy product processing, such as the pre-fermentation of products such as yogurt. At present, in order to meet the demand of people for yogurt with different flavors and different viscosities, different strains need to be added to the fermentation tank to produce products with different flavors.

[0003] In the current production process of yogurt, different proportions of different strains are usually added in the fermentation tank according to the requirements of the production process, such as adding 50 grams of A strain, 30 grams of B strain, and 20 grams of C strain for the fermentation of one ton of raw material liquid when producing yogurt with a certain flavor.

[0004] However, the existing strains are usually purchased from abroad, which is relatively expensive, and most of them are packaged in 100g. If only two tons of raw material liquid need to be prepared at a time, then the B strain and the C strain after opening cannot be used up at one time. Once the strain bag is opened, the unadded strains in the strain bag will also lose activity and cannot be used again after being sealed again, thereby causing waste of strains and increasing production costs. SUMMARY

[0005] In order to reduce the waste of strains in the production process and reduce the production cost, the present application provides an expansion system for dairy product strains.

[0006] The expansion system for dairy product strains provided by the present application adopts the following technical scheme:

[0007] An expansion system for dairy product strains, a sterile online mixing device, and an expansion tank for strain expansion fermentation;

[0008] A feed line is provided between the sterile online mixing device and the expansion tank, and an expansion tank feed valve is installed on the feed line;

[0009] A heat preservation layer is provided on the outer periphery of the expansion tank, and an ice water inlet valve is provided on the heat preservation layer to cool the expansion raw liquid in the expansion tank;

[0010] A discharge line is provided at the other end of the expansion tank, and a material quantitative discharge valve and a flow controller are provided on the discharge line.

[0011] By adopting the above technical solution, sterile raw material solution and inoculum are added to the aseptic online mixing device. The sterile raw material solution and inoculum are thoroughly mixed. Then, the feed valve of the expansion tank is opened, and the mixed solution enters the expansion tank for expansion fermentation. After fermentation is completed and the acidity of the raw material solution reaches 70%, the ice water inlet valve is opened, and ice water enters the insulation layer to cool the expansion stock solution stored in the expansion tank. The temperature inside the expansion tank is controlled to be reduced to 2℃-6℃ for storage. When it is necessary to retrieve the expansion stock solution, the material is extracted through the material metering outlet valve, and the flow controller can control the extraction speed of the liquid. Through the expansion effect of the expansion tank, the raw material can be fermented in large quantities at one time. The unused expansion stock solution can still be stored in the expansion tank and reused later, which can effectively reduce the waste of inoculum and effectively reduce production costs.

[0012] Optionally, it also includes a CIP cleaning station, and a culture tank cleaning and disinfection line is provided between the CIP cleaning station and the culture tank. A culture tank spray cleaning valve for cleaning and sterilizing the culture tank is provided on the culture tank cleaning and disinfection line.

[0013] The expansion tank cleaning and disinfection line is also equipped with an expansion tank cleaning return valve, so that the cleaning solution after cleaning is returned to the CIP cleaning station through the expansion tank cleaning and disinfection line.

[0014] By adopting the above technical solution, the expansion tank is cleaned and disinfected before expansion culture. The CIP cleaning station and the spray cleaning valve of the expansion tube are opened, and the cleaning solution enters the expansion tank along the cleaning and disinfection line to clean and sterilize it. After cleaning and disinfection, the cleaning solution is returned to the CIP cleaning station. Cleaning and disinfecting the expansion tank effectively prevents contamination of the sterile raw material solution and inoculum during fermentation, effectively ensuring the quality of the expansion stock solution and reducing production losses.

[0015] Optionally, a pressure sensor is installed inside the expansion tank, and a cleaning and breathing valve is installed on the expansion tank. When cleaning the expansion tank, the cleaning and breathing valve is opened to release pressure.

[0016] By adopting the above technical solution, the pressure inside the expansion tank will change during cleaning. The cleaning breather valve can effectively prevent the pressure inside the expansion tank from becoming too high, thus avoiding the expansion tank from rupturing and affecting the subsequent production schedule.

[0017] Optionally, it also includes a sterile air generating station and a sterile air line disposed between the sterile air generating station and the expansion tank;

[0018] The sterile air generator produces sterile air and introduces it into the expansion tank.

[0019] By adopting the above technical solutions, sterile air can provide a good fermentation environment for the strains, avoid contamination of the sterile raw material liquid and the strains during the fermentation process, ensure the quality of the expansion culture solution, and reduce production losses.

[0020] Optionally, it also includes a sterile steam generating station, one end of which is connected to the sterile air line, and the sterile air line is also connected to the CIP cleaning station;

[0021] A sterile air inlet valve is installed on the sterile air line to control the entry of sterile air into the expansion tank.

[0022] Before introducing sterile air into the expansion tank, the sterile steam generator is turned on and the sterile air inlet valve is turned off. The sterile steam disinfects the sterile air line and flows back to the CIP cleaning station.

[0023] By adopting the above technical solutions, sterile steam disinfection can further ensure the environmental quality within the sterile air line, prevent sterile air from being contaminated, that is, prevent the sterile raw material liquid and strains from being contaminated during the fermentation process, and ensure the quality of the expansion culture solution.

[0024] Optionally, a sampling valve for extracting the expansion raw material solution in the expansion tank is also provided on the expansion tank;

[0025] The sterile steam generator is also connected to the sterile cleaning line, and a sampling steam shut-off valve is installed on the sterile cleaning line. The sampling steam valve is located at the end of the sampling valve near the expansion tank.

[0026] The other end of the sampling valve is connected to the cleaning and disinfection line of the expansion tank.

[0027] When the expansion tank spray valve is closed, sterile steam enters the sampling valve through the sterile cleaning line to clean the sampling valve, and then flows back to the CIP cleaning station through the expansion tank cleaning and disinfection line.

[0028] By adopting the above technical solution, the sampling valve operator can conduct real-time testing of the mixture of sterile raw material liquid and inoculum fermenting in the expansion tank to monitor the fermentation degree of the mixture and ensure the quality of the expansion liquid. When the sampling valve is opened, air inevitably enters it; therefore, the sampling valve must be cleaned and sterilized after each sampling to minimize its impact on the fermenting mixture in the expansion tank.

[0029] Optionally, one end of the discharge line is connected to the CIP cleaning station, and the discharge line is also connected to the cleaning return line;

[0030] An expansion tank discharge valve is provided on the expansion tank, and the discharge line is connected to the expansion tank discharge valve;

[0031] The expansion tank discharge valve and the material metering discharge valve are closed, the cleaning fluid cleans the discharge line, and then flows back to the CIP cleaning station via the cleaning return line.

[0032] By adopting the above technical solution, the discharge line needs to be cleaned after each material extraction to prevent the residual propagation solution in the discharge line from continuing to ferment and affecting the environment inside the discharge line, and also to avoid affecting the propagation solution that will be extracted again.

[0033] Optionally, a cleaning return filter, a cleaning self-priming pump, and a cleaning check valve are provided on the cleaning return line.

[0034] By adopting the above technical solution, the cleaning return filter screen can remove impurities, allowing the cleaning fluid returned to the CIP cleaning station to be reused, thus reducing cleaning costs.

[0035] Optionally, multiple expansion tanks are provided, and the multiple expansion tanks are used alternately;

[0036] When using one expansion tank, close the feed valve and discharge valve of the other expansion tank.

[0037] By adopting the above technical solution, the setup of multiple expansion tanks allows for the simultaneous expansion of various flavors of yogurt, further improving the utilization rate of the starter culture and reducing production costs. Furthermore, when the demand for a particular flavor of yogurt is high, multiple expansion tanks can simultaneously expand that flavor, ensuring a normal supply of the expansion solution.

[0038] Optionally, a tank temperature sensor is installed inside the expansion tank, and an ice water return valve is also installed on the insulation layer.

[0039] During the process of cooling the raw material solution for expansion culture with ice water, the ice water return valve is opened to recover the ice water, and new ice water is introduced to continuously keep the raw material solution in the expansion culture tank warm.

[0040] By adopting the above technical solution, continuous heat preservation of the expansion tank can be achieved, and the utilization rate of ice water can be effectively improved, thereby reducing production costs.

[0041] In summary, this application includes at least one of the following beneficial technical effects:

[0042] 1. By setting up an aseptic online mixing device, a propagation tank, and a discharge line, the propagation tank can achieve one-time large-scale fermentation of raw materials. Unused propagation stock solution can still be stored in the propagation tank and can be used again later, which can effectively reduce the waste of strains and effectively reduce production costs.

[0043] 2. By setting up CIP cleaning stations, expansion tank cleaning and disinfection lines, and expansion tank spray cleaning valves, the cleaning and disinfection of expansion tanks can effectively prevent contamination of sterile raw material liquid and inoculum during fermentation, thus effectively ensuring the quality of the expansion stock solution and reducing production losses.

[0044] 3. By setting up a pressure sensor and a cleaning breather valve, the pressure inside the expansion tank will change during the cleaning process. The cleaning breather valve can effectively prevent the pressure inside the expansion tank from becoming too high, thus avoiding the expansion tank from rupturing and affecting the subsequent production schedule. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of a system for propagating microbial cultures used in dairy products.

[0046] Figure labeling: 1. Aseptic online mixing device; 11. Mixing feed valve; 12. Mixing discharge valve; 2. Expansion tank; 21. Insulation layer; 211. Ice water inlet valve; 212. Ice water return valve; 22. Pressure sensor; 23. Cleaning breather valve; 24. Sampling valve; 25. Sampling steam shut-off valve; 26. Tank temperature sensor; 3. Feed line; 31. Expansion tank feed valve; 32. Feed line shut-off valve; 33. Feed line cleaning check valve; 4. Discharge line; 41. Discharge line cleaning valve; 42. Discharge line anti-mixing valve; 43. Material quantitative discharge valve; 44. Flow controller; 45. Expansion tank discharge valve; 5. CIP cleaning station; 6. Expansion tank cleaning... Disinfection line; 61. Spray cleaning valve for expansion tank; 62. Cleaning return valve for expansion tank; 7. Sterile air generator station; 71. Sterile air line; 711. Sterile air inlet valve; 72. Compressed air valve; 73. Primary filter; 74. Compressed air regulating valve; 75. Compressed air shut-off valve; 76. Sterile air filter; 77. Steam shut-off valve; 8. Sterile steam generator station; 81. Sterile steam line; 82. Steam main valve; 83. Steam pressure gauge; 84. Steam pressure regulating valve; 85. Steam filter; 9. Sterile cleaning line; 10. Cleaning return line; 101. Cleaning return filter; 102. Cleaning self-priming pump; 103. Cleaning one-way pump. Detailed Implementation

[0047] In the description of this application, it should be noted that the terms "horizontal," "vertical," "closer," "farther," "upper," "lower," and "inner," etc., are based on the relative relationships shown in the accompanying drawings and are used only for the convenience of describing the invention and simplifying the description, and are not intended to indicate or imply that the process or module referred to must have a specific orientation, state, or operation, and therefore should not be construed as a limitation of the invention. The following description, in conjunction with the accompanying drawings... Figure 1 This application will be described in further detail below.

[0048] This application discloses a system for propagating microbial strains for dairy products.

[0049] A sterile online mixing device 1 for the propagation system of dairy product strains, a propagation tank 2 for the propagation and fermentation of strains, a feed line 3 connecting the sterile online mixing device 1 and the propagation tank 2, a discharge line 4 connected to the propagation tank 2, a CIP cleaning station 5, a propagation tank cleaning and disinfection line 6, a sterile air generating station 7, a sterile steam generating station 8, a sterile cleaning line 9, and a cleaning return line 10.

[0050] The aseptic online mixing device 1 is equipped with a mixing feed valve 11 and a mixing discharge valve 12, which are used to control the feeding and discharging of the aseptic online mixing device 1.

[0051] An insulation layer 21 is provided on the outer periphery of the expansion tank 2. An ice water inlet valve 211 and an ice water return valve 212 are installed on the insulation layer 21 to control the inflow and outflow of ice water within the insulation layer 21. A tank temperature sensor 26 is also installed inside the expansion tank 2. An expansion tank inlet valve 31 is installed on the feed line 3 between the aseptic online mixing device 1 and the expansion tank 2 to control the entry of the expansion stock solution into the expansion tank 2.

[0052] Open the mixing discharge valve 12 and add sterile raw material liquid and inoculum into the sterile online mixing device 1. The sterile raw material liquid and inoculum are thoroughly mixed. Then, open the mixing discharge valve 12 and the feed valve of the expansion tank 2. The mixed liquid enters the expansion tank 2 for expansion fermentation. After fermentation is completed, when the acidity of the raw material liquid reaches 70%, open the ice water inlet valve 211. Ice water enters the insulation layer 21 to cool the expansion liquid stored in the expansion tank 2. The temperature inside the expansion tank 2 is observed through the tank temperature sensor 26. The temperature inside the expansion tank 2 is controlled to drop to 2℃-6℃ and stored. While cooling the expansion raw material liquid with ice water, open the ice water return valve 212 to recover the ice water and introduce new ice water to continuously keep the raw material liquid in the expansion tank 2 warm.

[0053] A sampling valve 24 is also installed on the expansion tank 2. During the fermentation process, the staff can open the sampling valve 24 at any time to conduct real-time testing on the mixture of sterile raw material liquid and inoculum in the expansion tank 2, so as to keep track of the fermentation degree of the mixture and ensure the quality of the expansion liquid.

[0054] At the other end of the feed line 3, there is a feed line shut-off valve 32 and a feed line cleaning check valve 3. After the feed line 3 is cleaned, the cleaning fluid will flow back into the CIP cleaning station 5.

[0055] An expansion tank discharge valve 45 is installed on the discharge line 4 to control the entry and exit of the expansion tank 2. The expansion tank solution is discharged through the discharge line 4. A material metering discharge valve 43 and a flow controller 44 are installed sequentially at the discharge end of the discharge line 4. The material metering discharge valve 43 can control the extraction volume of the expansion tank solution, and the flow controller 44 can control the extraction speed of the expansion tank solution.

[0056] In this embodiment, two expansion tanks 2 are provided. It can be understood that the number of expansion tanks 2 can be adjusted according to production needs. The two expansion tanks 2 are used alternately. When one expansion tank 2 is in use, the expansion tank inlet valve 31 and expansion tank outlet valve 45 of the other expansion tank 2 can be closed.

[0057] The setup of multiple propagation tanks 2 allows for the simultaneous propagation of various flavors of yogurt, further improving the utilization rate of the starter culture and reducing production costs. Furthermore, when the demand for a particular flavor of yogurt is high, multiple propagation tanks 2 can simultaneously propagate that flavor, ensuring a stable supply of the propagation stock solution.

[0058] One end of the discharge line 4 is connected to the CIP cleaning station 5. A discharge line cleaning valve 41 of the first expansion tank is provided on the discharge line 4 between the CIP cleaning station 5 and the expansion tank discharge valve 45 of the first expansion tank. A discharge line anti-mixing valve 42 of the first expansion tank is provided on the other side of the expansion tank discharge valve 45.

[0059] On the other side of the discharge valve 45 of the second expansion tank, there is a discharge line anti-mixing valve 42 of the second expansion tank.

[0060] When it is necessary to add the culture medium, the discharge anti-mixing valve 42 of the discharge line can effectively prevent mixing between the first and second culture tanks during the extraction of the culture medium, which would affect the quality of the yogurt. The culture expansion function of culture tank 2 enables large-scale fermentation of raw materials in a single operation. Any unused culture medium can be stored in culture tank 2 and used again later, effectively reducing waste of the culture medium and lowering production costs.

[0061] The discharge line 4 is also connected to the cleaning return line 10. At the end of the cleaning return line 10, a cleaning return filter 101, a cleaning self-priming pump 102, and a cleaning one-way pump 103 are installed in sequence. The cleaning return line is connected to the CIP cleaning station. After each extraction of the expansion culture medium, the CIP cleaning station 5 is opened and the expansion tank discharge valve 45 is closed to clean the discharge line 4. This is to prevent the expansion culture medium remaining in the discharge line 4 from continuing to ferment and affecting the quality of the expansion culture medium discharged from the expansion tank 2 during subsequent extractions.

[0062] Before expansion culture, in addition to cleaning and disinfecting the aseptic online mixing device 1 and the feeding line 3 as necessary, the expansion tank 2 also needs to be cleaned and disinfected.

[0063] There are two expansion tank cleaning and disinfection lines 6, each corresponding to one of the two expansion tanks 2. One end of the expansion tank cleaning and disinfection line 6 is connected to the CIP cleaning station 5, and then to the expansion tank 2. An expansion tank spray cleaning valve 6 is installed on the expansion tank cleaning and disinfection line 6 to control the entry of cleaning solution into the expansion tank.

[0064] When it is necessary to clean the expansion tank 2, simply open the expansion tank spray cleaning valve 6. The expansion tank spray cleaning valve 6 will clean the expansion tank 2. The expansion tank cleaning and disinfection line 6 is connected to the discharge line 4, and an expansion tank cleaning return valve 62 is installed at the end of the expansion tank cleaning and disinfection line 6 so that the cleaning solution can flow back into the CIP cleaning station 5.

[0065] Meanwhile, a pressure sensor 22 is installed inside the expansion tank 2, and a cleaning breather valve 23 is installed on the expansion tank 2. When the expansion tank 2 is cleaned, the pressure inside the expansion tank 2 will change. The cleaning breather valve 23 can effectively prevent the pressure inside the expansion tank 2 from becoming too high, thus avoiding the expansion tank 2 from rupturing and affecting the subsequent production progress.

[0066] During fermentation, sterile air needs to be introduced into the expansion tank 2 to ensure the normal fermentation of the microorganisms. The sterile air generating station 7 can generate sterile air and continuously replenish sterile air into the expansion tank 2. A sterile air inlet valve 711 is installed on the sterile air line 74 to control the entry of sterile air into the expansion tank 2.

[0067] The sterile air generating station 7 is connected to a sterile air line 71. On the sterile air line 71, between the sterile air generating station 7 and the expansion tank 2, there are a compressed air valve 72, three primary filters 73, a compressed air regulating valve 74, a compressed air shut-off valve 75, and a sterile air filter 76 arranged in sequence.

[0068] The multiple filters ensure the compressed air is purified, creating a favorable fermentation environment for the microorganisms. Simultaneously, to control the pressure within expansion tank 2 during fermentation and prevent excessive or insufficient pressure, compressed air regulating valve 74 adjusts the compressed air to meet the fermentation requirements while maintaining a balanced pressure within expansion tank 2.

[0069] Similarly, before introducing sterile air into the expansion tank 2, the sterile steam generator station 8 needs to be turned on to sterilize the sterile air line 71. The sterile steam generator station 8 is connected to the sterile steam line 81, which is connected to the sterile air line 71. On the sterile steam line 81, between the connection point of the sterile steam generator station 8 and the sterile steam line 81 and the sterile air line 71, a steam main valve 82, a steam pressure gauge 83, a steam pressure regulating valve 84, another steam pressure gauge 83, and a steam filter 85 are installed in sequence.

[0070] The sterile steam generated in the sterile steam generator station 8 is pressurized. In order to ensure the safety of the pipeline, the pressure of the sterile steam needs to be tested first. After being adjusted by the steam pressure regulating valve 84, it is tested again and filtered before it can enter the sterile air line 71 to disinfect the sterile air line.

[0071] A steam shut-off valve 77 is provided at the connection between the sterile steam line 81 and the sterile air line 71 to control the entry and exit of sterile steam into the sterile air line 71.

[0072] Since the sterile air line 71 is also connected to the expansion tank 2, when sterilizing the sterile air line, the two sterile air inlet valves 711 that control the entry of sterile air into the expansion tank 2 should be closed to prevent sterile steam from entering the expansion tank 2.

[0073] Meanwhile, the sterile air line 71 is also connected to the CIP cleaning station 5, so after the sterile steam completes the disinfection of the sterile air line 71, it will flow back into the CIP cleaning station.

[0074] After the steam shut-off valve 77, the sterile air line 71 is connected to the sterile cleaning line 9. The sterile cleaning line 9 is equipped with a sampling steam shut-off valve 25 to control the entry of sterile steam into the sampling valve 25. The other end of the sterile cleaning line 9 is connected to the expansion tank cleaning and sterilization line 6.

[0075] Before disinfecting the sampling valve, the expansion tank spray cleaning valve 61 must be closed. Sterile air enters the sampling valve 24 through the sterile cleaning line 9 to clean and disinfect the sampling valve 24. Sterile steam will flow back to the CIP cleaning station along the expansion tank cleaning and sterilization line 6. Closing the expansion tank spray cleaning valve 61 can effectively prevent sterile steam from entering the expansion tank 2 and contaminating the expansion tank stock solution.

[0076] The implementation principle of the dairy product strain propagation system according to this application embodiment is as follows: Aseptic raw material solution and strain are added to the aseptic online mixing device 1. The aseptic raw material solution and strain are thoroughly mixed. Then, the feed valve of the propagation tank 2 is opened, and the mixed solution enters the propagation tank 2 for propagation and fermentation. After fermentation is complete and the acidity of the raw material solution reaches 70%, the ice water inlet valve 211 is opened, and ice water enters the insulation layer 21 to cool the propagation stock solution stored in the propagation tank 2. The temperature inside the propagation tank 2 is controlled to be reduced to 2℃-6℃ for storage. When the propagation stock solution needs to be retrieved, the material is extracted through the material metering discharge valve 43, and the flow controller 44 controls the extraction speed of the liquid. Through the propagation function of the propagation tank 2, large-scale fermentation of raw materials can be achieved in one go. Unused propagation stock solution can still be stored in the propagation tank 2 and reused later, effectively reducing strain waste and lowering production costs.

[0077] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A system for propagating microbial cultures for dairy products, characterized in that: An aseptic online mixing device (1) and an expansion tank (2) for the expansion and fermentation of microbial strains; a feed line (3) is provided between the aseptic online mixing device (1) and the expansion tank (2), and an expansion tank feed valve (31) is installed on the feed line (3); an insulation layer (21) is provided on the outer periphery of the expansion tank (2), and an ice water inlet valve (211) is provided on the insulation layer (21) to cool the expansion stock solution in the expansion tank (2); a discharge line (4) is provided at the other end of the expansion tank (2), and a material metering discharge valve (43) and a flow controller (44) are provided on the discharge line (4); It also includes a CIP cleaning station (5), and a culture tank cleaning and disinfection line (6) is provided between the CIP cleaning station (5) and the culture tank (2). A culture tank spray cleaning valve (61) for cleaning and sterilizing the culture tank (2) is provided on the culture tank cleaning and disinfection line (6); A culture tank (2) cleaning return valve is also provided on the culture tank cleaning and disinfection line (6), and the cleaning solution after cleaning is returned to the CIP cleaning station (5) through the culture tank cleaning and disinfection line (6); It also includes a sterile air generating station (7) and a sterile air line (71) disposed between the sterile air generating station (7) and the expansion tank (2); the sterile air generating station (7) generates sterile air and introduces it into the expansion tank (2); It also includes a sterile steam generator station (8), one end of which is connected to the sterile air line (71), which is also connected to the CIP cleaning station (5); a sterile air inlet valve (711) for controlling the entry of sterile air into the expansion tank (2) is provided on the sterile air line (71); before introducing sterile air into the expansion tank (2), the sterile steam generator station (8) is opened and the sterile air inlet valve (711) is closed, and the sterile steam disinfects the sterile air line (71) and flows back to the CIP cleaning station (5); A sampling valve (24) for extracting the culture raw material liquid in the culture tank (2) is also provided on the culture tank (2); a sterile cleaning line (9) is also connected to the sterile steam generating station (8), and a sampling steam shut-off valve (25) is provided on the sterile cleaning line (9). The sampling steam shut-off valve (25) is located at one end of the sampling valve (24) near the culture tank (2); the other end of the sampling valve (24) is connected to the culture tank cleaning and disinfection line (6); when the culture tank spray cleaning valve (61) is closed, sterile steam enters the sampling valve (24) from the sterile cleaning line (9) to clean the sampling valve (24), and then flows back to the CIP cleaning station (5) through the culture tank cleaning and disinfection line (6).

2. The system for propagating microbial cultures for dairy products according to claim 1, characterized in that: A pressure sensor (22) is installed inside the expansion tank (2), and a cleaning and breathing valve (23) is installed on the expansion tank (2). When cleaning the expansion tank (2), the cleaning and breathing valve (23) is opened to release pressure.

3. The system for propagating microbial cultures for dairy products according to claim 1, characterized in that: One end of the discharge line (4) is connected to the CIP cleaning station (5), and the discharge line (4) is also connected to the cleaning return line (10); an expansion tank discharge valve (45) is provided on the expansion tank (2), and the discharge line (4) is connected to the expansion tank discharge valve (45); the expansion tank discharge valve (45) and the material quantitative discharge valve (43) are closed, the cleaning liquid cleans the discharge line (4), and flows back to the CIP cleaning station (5) through the cleaning return line (10).

4. The system for propagating microbial cultures for dairy products according to claim 3, characterized in that: A cleaning return filter (101), a cleaning self-priming pump (102), and a cleaning check valve (103) are provided on the cleaning return line (10).

5. The system for propagating microbial cultures for dairy products according to claim 1, characterized in that: Multiple expansion tanks (2) are provided, and multiple expansion tanks (2) are used alternately; when using one expansion tank (2), the expansion tank inlet valve and outlet valve of another expansion tank (2) are closed.

6. The system for propagating microbial cultures for dairy products according to claim 1, characterized in that: A tank temperature sensor (26) is installed inside the expansion tank (2), and an ice water return valve (212) is also installed on the insulation layer (21). During the process of cooling the expansion raw material liquid with ice water, the ice water return valve (212) is opened to recover the ice water and introduce new ice water to continuously keep the expansion raw liquid in the expansion tank (2) warm.

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