Semi-finished dairy product preparation method and device

Abstract

The invention relates to the technical field of dairy product processing and manufacturing, and discloses a semi-finished dairy product preparation method and device.The method comprises the steps that collected raw milk is sterilized to obtain a standby milk material, and then the standby milk material is pre-stored; and concentrating the standby milk material to obtain the semi-finished dairy product. The semi-finished dairy product preparation method and the semi-finished dairy product preparation device disclosed by the invention are used for solving or improving the problems of more detection and unstable product quality of dairy product microbial colonies compared with those before improvement.

Description

Technical Field

[0001] The present application relates to the technical field of dairy product processing and manufacturing, and specifically to a method and device for preparing semi-finished dairy products. Background Art

[0002] Currently, dairy companies have two necessary steps in the production of semi-finished dairy products: one is the milk collection step, and the other is the pretreatment step.

[0003] In conventional technology, UHT ultra-high temperature sterilization is arranged in the pretreatment process. This treatment method can make the total number of microbial colonies in semi-finished dairy products meet the standard range. However, in the actual processing process, it is found that the taste of semi-finished dairy products is unstable and the product quality is inconsistent. Therefore, it cannot meet the corporate requirements of ensuring stable product quality. There may also be a batch of semi-finished dairy products that do not meet the standard for the total number of microbial colonies after sterilization. Therefore, the problem of excessive total number of microbial colonies in semi-finished dairy products cannot be completely solved. Summary of the invention

[0004] In view of this, the present application provides a method and device for preparing semi-finished dairy products to solve the problem that the total number of microbial colonies in semi-finished dairy products is relatively high and the differences between batches are obvious, resulting in unstable product quality, and even the total number of microbial colonies may still exceed the standard after sterilization.

[0005] In a first aspect, the present application provides a method for preparing a semi-finished dairy product, comprising: a milk collection process, sterilizing the collected raw milk to obtain a reserve milk material, and then pre-storing the reserve milk material; a pretreatment process, concentrating the reserve milk material to obtain a semi-finished dairy product.

[0006] Among them, the milk collection process mainly collects raw milk, inspects the raw milk, and puts the raw milk into the milk warehouse after it meets the national health standards. Then, the impurities and other substances in the milk are filtered out. Finally, after passing the inspection, it is preheated, homogenized, sterilized, cooled, and pre-stored to complete the milk collection process. After the milk collection process is completed, the pretreatment process is carried out, which includes milk conditioning, RO membrane concentration, cooling, and making semi-finished dairy products.

[0007] The difference between the milk collection process of the present invention and the original milk collection process is that the collected raw milk is sterilized by UHT in advance, which reduces the risk of a high total number of microbial colonies due to long storage time; the UHT ultra-high temperature sterilization is advanced to the milk collection process, and the microorganisms in the raw milk are killed in advance, which reduces the total number of microbial colonies in the raw milk and improves the quality and taste of the product. At the same time, the change between the pretreatment process of the present invention and the original pretreatment process is that the high-temperature sterilization is reduced, and the milk is directly adjusted-RO membrane concentration-cooling-making into semi-finished dairy products.

[0008] Beneficial effects: Generally speaking, the product quality of dairy products is closely related to the total number of microbial colonies. Normally, the lower the total number of microbial colonies in milk, the better the corresponding product quality. On the contrary, the higher the total number of microbial colonies in milk, the lower the corresponding product quality. Sterilizing raw milk before pre-storage can effectively reduce the total number of microbial colonies in raw milk and prevent the problem that the microorganisms in raw milk will continue to multiply in large quantities during the pre-storage period. The longer the storage time, the more the total number of microbial colonies in raw milk. Based on this problem, we sterilize the collected raw milk in advance to reduce the risk of a large number of microbial colonies due to long storage time, and then proceed to the subsequent steps after passing the inspection. In the subsequent pretreatment process, the total number of microbial colonies was found to be significantly reduced. If sterilization is performed in the original pretreatment process, microorganisms will begin to multiply during the pre-storage period. As the storage time increases, the total number of microbial colonies in the raw milk will increase, which will eventually lead to poor taste and unstable product quality. Therefore, setting the sterilization step before the pre-storage step of the milk collection process can improve the product quality of semi-finished dairy products.

[0009] In some embodiments, sterilization can be performed by UHT ultra-high temperature sterilization or pasteurization. In the milk collection process, pasteurization is preferably used to achieve a common mode of raw milk and raw milk sterilized by pasteurization, thereby improving the sterilization efficiency. The sterilization temperature of pasteurization is 83-87°C, and the sterilization time is 15s-20s; the sterilization temperature of UHT ultra-high temperature sterilization is 135-139°C, and the sterilization time is 4s-6s.

[0010] In an optional embodiment, before the collected raw milk is subjected to UHT ultra-high temperature sterilization, the raw milk is filtered to remove impurities in the raw milk; the filtered raw milk is homogenized by a homogenizer to increase the particle size and uniformity of milk solids in the raw milk, thereby improving the taste of the dairy product.

[0011] Beneficial effects: Milk filtration can effectively remove impurities in raw milk, such as dust, shed hair, grass clippings and other pollutants, thereby improving the sanitary quality of raw milk; preventing microorganisms on impurities from entering raw milk and affecting the quality of subsequent products; reducing the wear and blockage of production equipment by impurities, extending the service life of production equipment and reducing maintenance costs.

[0012] Homogenization is a physical process that breaks up the fat globules in raw milk and evenly distributes them in the raw milk, preventing the fat from floating up and forming stratification. This helps maintain the uniformity and stability of the raw milk. The broken and even distribution of fat globules makes the raw milk feel smoother in the mouth. Homogenization can make the nutrients more evenly distributed in the raw milk. The broken fat globules make the fat easier to be absorbed and utilized by the human body, thereby improving the utilization rate of the nutritional value. Homogenization can reduce stratification and the formation of sediment in raw milk, thereby slowing down the deterioration of raw milk and extending its shelf life.

[0013] It is further explained that filtering and homogenizing raw milk can improve the quality stability and safety of raw milk, and can also improve its taste and flavor to meet the needs of consumers. At the same time, these treatments also help protect production equipment, reduce production costs and extend the shelf life of raw milk.

[0014] In an optional embodiment, the raw milk is preheated before homogenization, preferably at a preheating temperature of 50-80°C.

[0015] Beneficial effects: Preheating the raw milk to increase its temperature can effectively kill microorganisms in the raw milk, reduce the risk of contamination during subsequent processing, and extend the shelf life of the product; and preheating can inactivate the activity of lipase in the raw milk, thereby preventing it from destroying the fat structure of the raw milk during processing and storage, which helps to maintain the uniformity and stability of the raw milk and prevent stratification and precipitation. At the same time, preheating can soften the fat globules in the raw milk and make them easier to be broken by the homogenizer, which not only reduces the energy consumption and wear of the homogenizer, but also improves the uniformity and stability of the raw milk after homogenization.

[0016] In an optional embodiment, the standby milk material is cooled before being pre-stored, and the cooling temperature is 1°C to 7°C.

[0017] In an optional embodiment, the pre-storage temperature of the standby milk material is 1°C to 7°C.

[0018] As an example, both the cooling temperature and the pre-storage temperature may be 1°C, 4°C or 7°C.

[0019] Beneficial effects: Low temperature environment can inhibit the growth and reproduction of microorganisms in raw milk. Low temperature storage can effectively extend the shelf life of raw milk; low temperature storage can retain the nutrients in raw milk; low temperature storage can slow down the degradation rate of various nutrients in raw milk, such as protein, fat, carbohydrates, vitamins and minerals, and maintain the nutritional value of raw milk.

[0020] In an optional embodiment, the standby milk is concentrated by using RO membrane concentration equipment to obtain concentrated milk. RO membrane concentration refers to reverse osmosis membrane concentration, which is a method of concentrating a solution by using reverse osmosis (RO) technology.

[0021] Beneficial effects: Different from the conventional falling film heat treatment process, the present invention adopts the RO membrane concentration cold treatment process. The RO membrane has a small pore size, which filters the water in the standby milk material and increases the concentration of milk solids in the dairy product. This process can remove a large amount of water while retaining the original flavor, color and nutritional value of the raw milk to the maximum extent, ensuring the quality of the concentrated raw milk and maintaining the flavor and nutrition.

[0022] RO membrane concentration does not require heating, has relatively low energy consumption, and is carried out continuously with high processing efficiency, which can significantly shorten the production cycle. RO membrane concentration can be carried out at room temperature, avoiding the impact of high-temperature treatment on raw milk quality. RO membrane concentration can adjust parameters such as pressure and flow according to different concentration requirements to achieve the ideal concentration effect, with high flexibility. After RO membrane replaces falling film, it saves the use of steam and ice water energy, reduces production costs, and brings obvious technical advantages to the enterprise.

[0023] In some embodiments, the raw milk concentrated by the RO membrane concentration device is respectively transported to the material tank and the tank to be loaded, and the raw milk in the material tank or the tank to be loaded is selected according to different processes. The water separated by the RO membrane concentration device is transported to the storage tank for storage and transported to the main pipeline for cleaning the inside of the main pipeline.

[0024] In an optional embodiment, the protein content of the concentrated milk obtained by RO membrane concentration equipment is controlled at 0.5% to 1.2%, and the total solid content is controlled at 13wt% to 19wt%. It should be noted that the use of RO membrane concentration equipment instead of falling film evaporator concentration in related technologies can save steam and ice water usage.

[0025] In an optional embodiment, before the standby milk is concentrated by the RO membrane concentration device, ingredients are added to the standby milk to adjust the milk to obtain different types of dairy products. After the standby milk is concentrated by the RO membrane concentration device, the concentrated milk is cooled to obtain semi-finished dairy products.

[0026] In an optional embodiment, after the raw milk is sterilized, the total number of microbial colonies in the semi-finished dairy product is controlled to be below 100 CUF / ML.

[0027] In summary of the above implementation, the overall process is to collect raw milk, filter the collected raw milk to remove impurities in the raw milk, preheat the filtered raw milk to kill some microorganisms in the raw milk, and then homogenize the raw milk with a homogenizer to improve the quality and safety of the raw milk, improve its taste and flavor, and obtain standby milk material to improve the quality and taste of the standby milk material, and cool the standby milk material for pre-storage. The cooling and pre-storage temperature is 1°C. The low temperature can inhibit the growth and reproduction of microorganisms in the raw milk and effectively extend the shelf life of the raw milk. In the pretreatment process, the ingredients are added to the standby milk material for milk adjustment, and after milk adjustment, the milk is concentrated by RO membrane concentration equipment to obtain a semi-finished dairy product, and the semi-finished dairy product is cooled and stored. After concentration, the protein and total solids content of the standby milk material can be increased, so that the protein content is as low as 0.5% and the total solids content is as low as 13wt%.

[0028] It should be noted that the protein content of the concentrated standby milk material can be 0.5% or 0.9% or 1.2%; the total solid content of the concentrated standby milk material can be 13wt% or 16wt% or 19wt%, and the taste of the dairy product is better.

[0029] In a second aspect, the present application also provides a semi-finished dairy product preparation device, such as Figure 2 As shown, it includes: a raw milk warehouse, a clean milk filtering device, a preheating device, a homogenizer homogenizing device, a UHT ultra-high temperature sterilization device, a first cooling device, a pre-storage device, a milk conditioning device, an RO membrane concentration device, a second cooling device and a semi-finished dairy product storage milk warehouse.

[0030] The collected raw milk is first stored in a milk silo, and the raw milk in the milk silo is transported to a filtering device through a pipeline, and impurities in the raw milk are removed by the filtering device. The filtered raw milk is transported to a preheating device for heating, which can kill some microorganisms, and increasing the temperature of the raw milk helps to improve the homogenization effect of the raw milk in the homogenizing device. The homogenized raw milk is transported to a sterilizing device through a pipeline, and the sterilizing device adopts a pasteurization method for sterilization. After sterilization, a standby milk material is obtained, which is cooled by a first cooling device and stored in a pre-storage device for use.

[0031] When pre-processing the reserve milk, it is conveyed to the milk conditioning device, and additives are added to the reserve milk to obtain different types of dairy products. The reserve milk is concentrated by the RO membrane concentration device to increase the protein and total solid content of the reserve milk to obtain a semi-finished dairy product, which is then cooled and stored.

[0032] In an optional implementation, the homogenizing device of the homogenizer is set to variable frequency start, which can achieve variable frequency control and save energy consumption.

[0033] Frequency conversion starting is to convert the AC power of the power supply into DC power through the inverter, and then convert the DC power into AC power with adjustable frequency through filtering and inversion process, so as to achieve precise control of the motor speed and starting process. It can reduce the impact of the large current on the power grid at the moment of motor starting, and meet the various needs of motor starting and speed regulation in industrial production sites.

[0034] Frequency conversion control uses a frequency converter to convert a fixed frequency AC power supply (such as 50Hz or 60Hz industrial frequency power supply) into a variable frequency and voltage to achieve precise control of the motor speed. By adjusting the power supply frequency, the frequency converter can change the motor speed to meet different production needs and process requirements. Compared with traditional motor control methods, it has higher efficiency and response speed.

[0035] In an optional embodiment, the original related technology combines the falling film device and the sterilization device into one, and the equipment operation time is up to 15 hours. The present application discloses that after the RO membrane concentration device replaces the falling film device and operates independently, the sterilization device also operates independently, and the equipment operation time is extended to a maximum of 20 hours, thereby improving the equipment utilization efficiency and being able to filter more raw milk. The extended operation time of the RO membrane concentration device can save more energy consumption such as water, electricity and gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 This is a flow chart of a method for preparing a semi-finished dairy product according to an embodiment of the present application;

[0038] Figure 2 This is a schematic structural diagram of a semi-finished dairy product preparation device according to an embodiment of the present application;

[0039] Figure 3 The present invention is a flow chart of a method for preparing semi-finished dairy products in the related art. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of this application.

[0041] Combine the following Figures 1 to 3 , describing an embodiment of the present application.

[0042] Embodiment 1:

[0043] A method for preparing a semi-finished dairy product, comprising:

[0044] Milk collection process: collecting raw milk, and filtering the collected raw milk with a milk purification filter device, wherein the filter assembly used in the milk purification filter device has a filter aperture of 0.50 mm, to remove impurities in the raw milk, and then preheating the raw milk at a temperature of 50°C, so that it is easier to be broken by the homogenizer in the subsequent homogenization process, thereby improving the uniformity and stability of the raw milk; homogenizing after preheating, using a high-pressure homogenizer, the operating condition of the high-pressure homogenizer is a total pressure of 150 bar; then pasteurizing the homogenized raw milk, the pasteurization temperature is 85°C, and the sterilization time is 18s; after sterilization, the raw milk is cooled at a cooling temperature of 7°C, and the raw milk is pre-stored to obtain standby milk material, and the pre-storage temperature is 1°C.

[0045] Pretreatment process: adding ingredients to the standby milk to adjust the milk, and after the adjustment, using RO membrane concentration equipment to concentrate the standby milk, remove part of the water in the standby milk, and increase the protein and total solid content, wherein the protein content is controlled at 0.8%, and the total solid content is controlled to 17wt%, forming a semi-finished dairy product, which is then stored at a storage temperature of 1°C.

[0046] Embodiment 2:

[0047] A method for preparing a semi-finished dairy product, comprising:

[0048] Milk collection process: collect raw milk, and filter the collected raw milk to remove impurities in the raw milk. The filter assembly used in the clean milk filtration device has a filtration aperture of 0.50 mm; then preheat the raw milk at a preheating temperature of 80°C, so that it is easier to be broken by the homogenizer in the subsequent homogenization process, thereby improving the uniformity and stability of the raw milk; homogenize after preheating at a homogenization pressure of 170 bar; then pasteurize the homogenized raw milk at a pasteurization temperature of 87°C for 20 seconds; after sterilization, cool the raw milk at a cooling temperature of 1°C, and pre-store the raw milk to obtain standby milk material at a pre-storage temperature of 3°C.

[0049] The pretreatment process is as follows: ingredients are added to the standby milk to adjust the milk. After the adjustment, the standby milk is concentrated by RO membrane concentration equipment to remove part of the water in the standby milk and increase the protein and total solid content. The protein content is controlled at 0.5% and the total solid content is controlled to 13wt% to form a semi-finished dairy product, which is then stored at a storage temperature of 3°C.

[0050] Embodiment 3:

[0051] A method for preparing a semi-finished dairy product, comprising:

[0052] Milk collection process: collect raw milk, and filter the collected raw milk to remove impurities in the raw milk. The filter assembly used in the clean milk filtration device has a filter aperture of 0.50mm; then preheat the raw milk at a temperature of 50°C, so that it is easier to be broken by the homogenizer in the subsequent homogenization process, thereby improving the uniformity and stability of the raw milk; homogenize after preheating at a homogenization pressure of 150bar; then pasteurize the homogenized raw milk at a pasteurization temperature of 83°C for 15s; after sterilization, cool the raw milk at a cooling temperature of 5°C, and pre-store the raw milk to obtain standby milk material at a pre-storage temperature of 7°C.

[0053] Pretreatment process: adding ingredients to the standby milk to adjust the milk, and after the adjustment, using RO membrane concentration equipment to concentrate the standby milk, remove part of the water in the standby milk, and increase the protein and total solid content, wherein the protein content is controlled at 1.2%, and the total solid content is controlled to 19wt%, forming a semi-finished dairy product, which is then stored at a storage temperature of 7°C.

[0054] Embodiment 4:

[0055] A method for preparing a semi-finished dairy product, comprising:

[0056] Milk collection process: collecting raw milk, and filtering the collected raw milk with a milk purification filter device, wherein the filter assembly used in the milk purification filter device has a filter aperture of 0.50 mm, to remove impurities in the raw milk, and then pasteurizing the raw milk, the pasteurization temperature is 85°C, and the sterilization time is 18s; after the sterilization, the raw milk is cooled, the cooling temperature is 7°C, and the raw milk is pre-stored to obtain standby milk, and the pre-storage temperature is 1°C.

[0057] Pretreatment process: adding ingredients to the standby milk to adjust the milk, and preheating the milk after adjusting the milk. The preheating temperature is 50°C, so that it is easier to be broken by the homogenizer in the subsequent homogenization process, thereby improving the uniformity and stability of the raw milk; homogenizing after preheating, using a high-pressure homogenizer for homogenization, and the operating condition of the high-pressure homogenizer is a total pressure of 150 bar; then using an RO membrane concentration device to concentrate the standby milk after homogenization, remove part of the water in the standby milk, and increase the protein and total solids content, wherein the protein content is controlled at 0.8%, and the total solids content is controlled to reach 17wt%, forming a semi-finished dairy product, which is then stored at a storage temperature of 1°C.

[0058] Embodiment 5:

[0059] A method for preparing a semi-finished dairy product, comprising:

[0060] Milk collection process: collecting raw milk and filtering the collected raw milk with a milk purification filter, wherein the filter assembly used in the milk purification filter has a filtration aperture of 0.50 mm, to remove impurities in the raw milk, and then homogenizing the raw milk with a high-pressure homogenizer, the operating condition of the high-pressure homogenizer is a total pressure of 150 bar; then pasteurizing the homogenized raw milk, the pasteurization temperature is 85°C, and the sterilization time is 18s; after the sterilization, the raw milk is cooled at a cooling temperature of 7°C, and the raw milk is pre-stored to obtain standby milk material, and the pre-storage temperature is 1°C.

[0061] Pretreatment process: adding ingredients to the standby milk to adjust the milk, and after the adjustment, using RO membrane concentration equipment to concentrate the standby milk, remove part of the water in the standby milk, and increase the protein and total solid content, wherein the protein content is controlled at 0.8%, and the total solid content is controlled to 17wt%, forming a semi-finished dairy product, which is then stored at a storage temperature of 1°C.

[0062] Comparative Example 1:

[0063] Milk collection process: collecting raw milk, filtering the collected raw milk to remove impurities in the raw milk, the filter assembly used in the milk filtering device has a filter aperture of 0.50 mm, cooling the filtered raw milk at a cooling temperature of 7°C, and pre-storing it at a pre-storage temperature of 1°C;

[0064] Pretreatment process: adding ingredients to the pre-stored raw milk to adjust the milk, and then preheating the raw milk at a temperature of 50°C, so that it is easier to be broken by a homogenizer in the subsequent homogenization process, thereby improving the uniformity and stability of the raw milk; homogenizing after preheating, using a high-pressure homogenizer, and the operating condition of the high-pressure homogenizer is a total pressure of 150 bar; then pasteurizing the homogenized raw milk, the pasteurization temperature is 85°C, and the sterilization time is 18s; after the sterilization, the raw milk is cooled at a cooling temperature of 1°C, and then the sterilized raw milk is concentrated using an RO membrane concentration device to remove part of the water in the raw milk and increase the protein and total solids content, wherein the protein content is controlled at about 0.8% and the total solids content is controlled at about 17wt%, forming a semi-finished dairy product, and then storing it at a storage temperature of 1°C.

[0065] Experimental example:

[0066] In the detection of the total number of microbial colonies, in the related technology adopted in Comparative Example 1, the process flow shown in Comparative Example 1 is adopted, and the sterilization step is set in the pretreatment process. The final detection experimental sample data is shown in Table 1 below:

[0067] Table 1

[0068]

[0069] It can be seen from the data in Table 1 above that the average value of the original total colony count of the relevant technology adopted in Comparative Example 1 is above 100CUF / ML, the total colony count of some samples is below 100CUF / ML, and the total microbial colony count of some samples is above 100CUF / ML, but the range between the highest total microbial colony count and the lowest total microbial colony count is relatively large, and the maximum difference is 290CUF / ML. The quality and taste of the overall product are not balanced enough, and the quality and taste differences between the samples are large. There are large differences in quality and taste between the dairy products prepared in the later process. The quality and taste of the overall product are unbalanced, which affects the quality stability of the product.

[0070] The present application adopts the process flow shown in Example 1, and sets the sterilization step in the milk collection process. The experimental data of the test samples finally obtained are shown in Table 2 below:

[0071] Table 2

[0072]

[0073]

[0074] In the data in Table 2 above, the total microbial colony counts are all below 100CUF / ML, and the range between the highest and lowest total microbial colony counts is relatively small, with the maximum difference being 30CUF / ML. The quality and taste of the overall product are more balanced and stable, and the quality and taste differences between samples are smaller. Therefore, the quality and taste differences between dairy products prepared using the later process are smaller, the quality and taste of the overall product are more balanced, and the quality of the product is more stable.

[0075] In summary, the scheme in Comparative Example 1 sterilizes the dairy products in the pretreatment process after pre-storage, and the total number of microbial colonies in the dairy products is relatively high, averaging above 100CUF / ML, with a maximum of 340CUF / ML, and the maximum difference in the total number of colonies of the samples is 290CUF / ML. The quality and taste of the samples vary greatly, affecting the overall quality of the product. With reference to the process of the present application, the sterilization step is adjusted to the milk collection process and advanced to before pre-storage, and the total number of microbial colonies of the obtained dairy products is relatively low, averaging below 100CUF / ML, with a maximum of 40CUF / ML and a minimum of below 10CUF / ML. The maximum difference in the total number of microbial colonies of the samples is 30CUF / ML, and the quality and taste of the samples vary slightly, thereby improving the stability of the overall quality of the product.

[0076] At the same time, the present invention verifies that the semi-finished dairy products prepared using other parameter conditions in Examples 2 to 3 have no significant difference in total colony count from that in Example 1 after testing, and also have the effects of low total colony count, no significant difference between batches, and stable product quality.

[0077] In Example 4, since the preheating and homogenization steps were adjusted to the pretreatment step, the total microbial colony count of the final dairy product increased, but was still below 60CUF / ML, with the highest being 60CUF / ML and the lowest being 20CUF / ML. The maximum difference in the total microbial colony count of the samples was 40CUF / ML. The total microbial colony count of the samples and the differences between batches increased, but the increase was not significant.

[0078] In Example 5, since there is no preheating step, the total microbial colony count of the final dairy product is increased, but it is still below 70CUF / ML, the highest is 70CUF / ML, and the lowest is 30CUF / ML. The maximum difference in the total microbial colony count of the samples is 40CUF / ML. The total microbial colony count of the samples has increased, but the increase is not significant, and the difference in the total microbial colony count between batches has not increased significantly.

[0079] In addition, the present invention also verifies that UHT ultra-high temperature sterilization is used to replace the pasteurization method in Example 1 and Comparative Example 1. The UHT ultra-high temperature sterilization parameters are set as a sterilization temperature of 135-139° C. and a sterilization time of 4s-6s. Under the sterilization parameter conditions, the conclusions of Example 1 and Comparative Example 1 are basically consistent with the conclusions of pasteurization. Compared with the scheme of Comparative Example 1, the scheme of Example 1 has the advantages of low total colony count, no obvious difference between batches, and stable product quality.

[0080] That is, adjusting the sterilization process to the milk collection process can significantly reduce the total number of microbial colonies in dairy products and effectively improve the quality and taste of dairy products; at the same time, preheating before homogenization can also sterilize the raw milk, further reduce the total number of colonies and improve the quality of dairy products.

[0081] Although the embodiments of the present application are described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present application, and such modifications and variations are all within the scope defined by the attached present application.

Claims

1. A method for preparing a semi-finished dairy product, characterized in that: include: In the milk collection process, the collected raw milk is sterilized to obtain the standby milk material, which is then pre-stored; In the pretreatment step, the standby milk material is concentrated to obtain a semi-finished dairy product.

2. The method for preparing a semi-finished dairy product according to claim 1, characterized in that: Before sterilizing the collected raw milk, filtering the raw milk; The filtered raw milk is homogenized.

3. The method for preparing a semi-finished dairy product according to claim 2, characterized in that: Before the raw milk is homogenized, the raw milk is preheated.

4. The method for preparing a semi-finished dairy product according to claim 3, characterized in that: Before pre-storing the standby milk material, the standby milk material is cooled at a cooling temperature of 1°C to 7°C.

5. The method for preparing a semi-finished dairy product according to any one of claims 1 to 4, characterized in that: The pre-storage temperature of the standby milk material is 1°C to 7°C.

6. The method for preparing a semi-finished dairy product according to claim 1, characterized in that: The standby milk is concentrated by using RO membrane concentration equipment to obtain concentrated milk.

7. The method for preparing a semi-finished dairy product according to claim 6, characterized in that: The protein content in the concentrated milk obtained by concentration by the RO membrane concentration device is controlled at 0.5% to 1.2%, and the total solid content is controlled at 13wt% to 19wt%.

8. The method for preparing a semi-finished dairy product according to claim 6, characterized in that: Before the standby milk material is concentrated by the RO membrane concentration device, ingredients are added to the standby milk material to adjust the milk so as to obtain different types of dairy products. After the standby milk material is concentrated by the RO membrane concentration device, the concentrated milk material is cooled to obtain semi-finished dairy products.

9. The method for preparing a semi-finished dairy product according to claim 1, characterized in that: After sterilizing the raw milk, the total colony count in the standby milk is controlled to be below 100 CFU / mL.

10. A semi-finished dairy product preparation device, characterized in that: include: The milk warehouse, the filtering device, the preheating device, the homogenizing device, the sterilizing device, the first cooling device, the pre-storage device, the milk conditioning device, the RO membrane concentration device, the second cooling device and the semi-finished dairy product storage device are sequentially connected.

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