Processing technology of low-bacterium wheat flour

Abstract

The invention discloses a processing technology of low-bacterium wheat flour, and belongs to the field of flour milling of wheat. The process disclosed by the invention aims at remarkably reducing the content of microorganisms in the finished product flour and improving the sanitary quality and the safety of the wheat flour by introducing a pulsed electric field technology and combining with comprehensive optimization of tempering, grinding, flour cleaning and an air suction system. Especially in the grinding process, parameters of the grinding roller are dynamically adjusted according to the gluten strength and moisture of wheat, and it is guaranteed that the granularity of ground materials is accurate and controllable. The process not only can improve the purity of the wheat flour, but also can achieve a remarkable bacterium-reducing effect by controlling moisture and granularity in the whole process, is suitable for producing various wheat flour products such as low gluten, medium gluten and high gluten, and provides a novel safe and reliable method for preparing the low-bacterium wheat flour for the food industry.

Description

Technical Field

[0001] The invention belongs to the field of wheat flour milling, and in particular relates to a processing technology for low-bacteria wheat flour. Background Art

[0002] Wheat flour is a basic food raw material widely used around the world. One of the main challenges in its production process is to control the microbial content. In the traditional flour production process, the presence of microorganisms is inevitable, especially in the outer layers of wheat grains (such as bran and endosperm), where the number of microorganisms is relatively concentrated. Therefore, how to effectively reduce the microbial content in the flour-making process has become a core issue in ensuring food safety and improving product quality.

[0003] Existing microbial control technologies usually use physical means such as chemical fungicides or high temperature treatment. Although they can reduce the microbial load to a certain extent, these methods have significant limitations. On the one hand, chemical treatment can easily lead to product residues, affecting food safety and consumer health; on the other hand, although physical means such as high temperature treatment are effective, they may have an adverse effect on the physical properties of wheat and reduce the quality of flour.

[0004] At the same time, the traditional flour-making process has limited optimization for key links such as conditioning and powder purification, especially in terms of wheat moisture control and the separation of bran and endosperm, which often have deficiencies. In particular, conditioning, as a key link, not only affects the quality of flour, but also plays an important role in microbial control and subsequent processing performance. Traditional conditioning methods mostly rely on static moisture migration or mechanical stirring, but due to their limited physical disturbance effect, the migration speed of moisture inside wheat grains is often slow and the penetration depth is insufficient. This limitation leads to uneven distribution of moisture in the grains, especially it is difficult to effectively penetrate into the endosperm layer, which in turn causes problems such as poor separation of bran and endosperm and microbial growth.

[0005] However, in the processes reported in existing reports (such as CN103392979A and CN105767072A), the production processes of wheat flour have the independence of conditioning, grinding and powder cleaning processes, resulting in a lack of coordination and optimization among the processes, especially in terms of microbial control, and it is difficult to achieve significant results; moreover, the parameters of the conditioning, grinding roller and suction system are difficult to flexibly adjust according to the characteristics of wheat, resulting in a high content of microorganisms in the finished flour and unstable flour quality.

[0006] Therefore, the existing technical means still have a lot of room for improvement in terms of microbial control, process adaptability and product quality improvement. There is an urgent need for a more refined process method that can ensure the sanitary quality and stability of flour without relying on chemical additives or high-temperature treatment, while improving the physical properties and processing performance of the product. Summary of the invention

[0007] [Technical issues]

[0008] The existing preparation methods of low-bacteria wheat flour mainly focus on sterilizing wheat grains, milling process or finished flour by physical or chemical means, but there are few studies on optimizing the entire milling process to improve flour quality. The purpose of the present invention is to optimize the milling process and the conditioning process for low-bacteria effects, and provide a production method for low-bacteria wheat flour without chemical treatment. The method does not conflict with the existing sterilization methods, and effectively improves the quality and safety of the product while improving production efficiency.

[0009] [Technical solution]

[0010] The present invention achieves effective control of the number of microorganisms in wheat flour and effectively improves the quality and safety of the product through powder route process regulation and further joint regulation of the wheat route and powder route process. No chemical reagents are added or used in the process, and the technology is green, environmentally friendly and safe.

[0011] The present invention provides a processing technology for low-bacteria wheat flour, comprising the following steps:

[0012] (1) Primary cleaning: The wheat is vacuumed and then screened using a rotary vibrating screen, and a circulating air suction system is used to remove light impurities to obtain primary cleaned wheat;

[0013] (2) cleaning the raw wheat: subjecting the pre-cleaned wheat obtained in step (1) to screening, air suction, stone removal, and threshing to obtain cleaned wheat;

[0014] (3) Tempering treatment: adding sterile water to the cleaned wheat obtained in step (2), using high-frequency vibration waves to assist in tempering, and applying an alternating magnetic field treatment in the tempering bin to obtain tempered wheat;

[0015] (4) Cleaning the wheat: The wheat after conditioning obtained in step (3) is processed in sequence by a high-efficiency thresher → a rotary vibrating screen → a circulating air suction machine → a stone remover → a color sorter to obtain wheat to be ground into flour;

[0016] (5) Flour making: the wheat to be ground obtained in step (4) is subjected to a flour making process of grinding, beating the bran and cleaning the flour, wherein the flour grinding includes a husk grinding section (section B), a core grinding section (section M), a slag grinding section (section S) and a tail grinding section (section T), and the husk grinding section and the core grinding section are selected to discharge flour from the powder pipe, and the flour is mixed to obtain low-bacteria wheat;

[0017] When the wheat is medium or high gluten wheat, the rolling distance parameters of the skin grinding section are: 1B: 0.48-0.50mm, 2B: 0.26-0.30mm, 3B: 0.16-0.18mm, 4B: 0.08-0.10mm, 5B: 0.02-0.03mm; the rolling distance of the core grinding section is: 1M: 0.018-0.020mm, 2M: 0.015-0.018mm, 3M: 0.014-0.016mm, 4M: 0.012-0.014mm;

[0018] When wheat is low-gluten wheat, the rolling distance parameters of the skin grinding section are: 1B: 0.52-0.58mm, 2B: 0.30-0.35mm, 3B: 0.20-0.25mm, 4B: 0.10-0.15mm, 5B: 0.04-0.06mm; the rolling distance parameters of the core grinding section are: 1M: 0.014-0.016mm, 2M: 0.012-0.014mm, 3M: 0.010-0.012mm, 4M: 0.008-0.010mm.

[0019] In one embodiment of the present invention, the total colony count in the low-bacteria wheat flour does not exceed 1000 CFU / g.

[0020] In one embodiment of the present invention, in step (1), the wheat raw grain is first subjected to a 360-degree vacuum treatment before entering the milling process, and then is preliminarily screened through two high-efficiency rotary vibrating screens, and a circulating suction system is used to remove light impurities.

[0021] In one embodiment of the present invention, in step (2), after step (1), the wheat is processed in sequence through a vibrating screen, a stone remover, a wheat thresher and an air suction device to remove impurities and fine particles. The entire cleaning process includes three screenings, three air suctions, two stone removals and two wheat threshers. The fully cleaned wheat enters a wheat conditioning bin to prepare for conditioning.

[0022] As an embodiment of the present invention, the high-frequency vibration wave assisted conditioning technology in step (3) of the present invention has brought significant improvements to the wheat tempering process through an innovative physical disturbance mechanism. The high-frequency vibration wave assisted conditioning machine is based on the high-frequency vibration wave technology driven by a motor, which can significantly accelerate the penetration of water from the surface layer to the inner layer of wheat, thereby effectively optimizing the moisture distribution during the conditioning process. The high-frequency vibration wave assisted conditioning machine uses a high-speed rotating motor system to stimulate the device casing to generate high-frequency vibration waves. This vibration wave stimulates the movement of water molecules through the rapid switching and action of the physical force field, thereby destroying the moisture tension on the surface of the wheat grains. Through this high-frequency vibration, water can break through the barrier of the wheat surface more quickly and quickly penetrate into the deep endosperm layer, greatly improving the penetration rate and distribution uniformity of water.

[0023] Compared with traditional conditioning, high-frequency vibration wave assisted conditioning greatly reduces the time that water stays on the surface of grains by virtue of its precisely controlled high-frequency vibration, and reduces the microbial breeding environment caused by excessive accumulation of water on the surface of wheat. At the same time, the physical disturbance of the vibration wave also enhances the diffusion rate of water, allowing water to penetrate more evenly into all layers of the wheat grain, especially the core area of ​​the endosperm which is more difficult to penetrate.

[0024] As an embodiment of the present invention, the high-frequency vibration wave assisted conditioning in step (3) uses a device model A, with an operating frequency of 180-200 Hz and a vibration speed of 5800 rpm. The high-speed operation of the motor drives the shell to vibrate at a high speed, ensuring that the moisture of the wheat grains is evenly penetrated into the endosperm layer during the conditioning process, thereby improving the conditioning effect.

[0025] As an embodiment of the present invention, when the tempering object in step (3) is low-gluten wheat, high-frequency vibration waves are used to assist the tempering, the tempering time is 4-8 hours, and the tempering moisture is controlled at 14.3±0.2%;

[0026] As an embodiment of the present invention, when the tempering object in step (3) is medium-gluten wheat, high-frequency vibration wave-assisted tempering is used for 8-12 hours, and then a second tempering is performed for 6 hours by a plate-beating water-dampening method, and the tempering moisture is controlled at 14.6±0.2%;

[0027] As an embodiment of the present invention, when the tempering object in step (3) is high-gluten wheat, high-frequency vibration waves are used to assist in tempering for 14-18 hours, and then a secondary tempering is performed for 6 hours by a plate-beating water-dampening method, and the tempering moisture is controlled at 15.0±0.2%.

[0028] As an embodiment of the present invention, during the secondary conditioning in step (3), the first water addition amount is 80% of the total water addition amount, and the second water addition amount is 20% of the total water addition amount, to ensure that the water gradually penetrates into the wheat endosperm layer to avoid bran rupture and uneven moisture.

[0029] As an embodiment of the present invention, the dampening machine used in the dampening method is model FZSQ, with a rotation speed of 480 rpm. The arc-shaped dampening design allows the wheat to absorb water more evenly during the secondary conditioning process, enhances the toughness of the bran, and avoids the bran from breaking in subsequent processes.

[0030] In one embodiment of the present invention, in step (3), for medium-high gluten wheat, the moisture is further adjusted through a secondary conditioning process to ensure uniform moisture penetration and microbial control. At the same time, an alternating magnetic field of a certain intensity is applied to the wheat grains during the conditioning process to inhibit microbial reproduction.

[0031] In one embodiment of the present invention, the secondary conditioning process can improve the precision and uniformity of the conditioning stage. The first watering is performed with a large amount of water for initial moistening, while the second conditioning is further evenly penetrated into the deep endosperm with a small amount of water. This staged conditioning strategy not only ensures the hierarchical distribution of moisture, but also significantly enhances the toughness of the bran, preventing it from being broken due to excessive fragility during the subsequent flour making process. The meticulous design of this process makes the separation of bran more thorough during the powder cleaning process, reduces the possibility of bran entering the finished flour, and ultimately improves the purity of the flour and its competitiveness in the high-end market.

[0032] As an embodiment of the present invention, during the tempering of wheat, high humidity and temperature environment can easily promote the rapid reproduction of microorganisms, especially some bacteria and fungi (such as Escherichia coli and mold) can cause the corruption and quality deterioration of wheat, increasing food safety risks. Traditional microbial inhibition methods usually rely on chemical treatment or high temperature disinfection, but these methods may destroy the natural nutrients of wheat or leave chemical residues, which do not meet the high standards of modern consumers for food safety and quality. Alternating magnetic field technology provides a non-thermal, non-chemical microbial inhibition method. Alternating magnetic field is an electromagnetic field that changes with time, which achieves physical inhibition of microorganisms by continuously changing the direction and intensity of the magnetic field. Alternating magnetic field can induce microscopic pores in microbial cell membranes, a phenomenon called "electroporation". Under the action of low-frequency alternating magnetic field (30-100Hz), the permeability of microbial cell membranes increases, and the flow of ions and molecules inside and outside the cells is disturbed, resulting in an unstable cell environment, which ultimately inhibits the proliferation of microorganisms. The changing frequency of the alternating magnetic field can affect the ion channels and molecular motion in microbial cells, especially the migration of ions such as calcium, sodium, and potassium. The ion imbalance induced by the alternating magnetic field will increase the reactive oxygen species (ROS) in microbial cells, causing oxidative stress reactions inside the cells. These reactive oxygen molecules can damage the DNA, protein and lipid structures of bacteria, thereby effectively inhibiting their growth. The oxidative stress and ion imbalance caused by the alternating magnetic field in microbial cells will further interfere with the metabolic process of the cells, especially inhibiting the processes of DNA replication, RNA transcription and protein synthesis, fundamentally preventing the reproduction of microorganisms.

[0033] As an embodiment of the present invention, the alternating magnetic field treatment system in step (3) is modularized by combining multiple magnetic field sources, using multiple alternating magnetic field units. Magnetic field equipment is arranged around the warehouse (such as corners) and on the top of the warehouse to ensure uniform magnetic field coverage.

[0034] As an embodiment of the present invention, the electromagnetic field strength used in the alternating magnetic field in step (3) is 1-50 mT, and the frequency is 20-100 Hz. Furthermore, the pulse electric field strength is 10-30 mT, and the frequency is 30-50 Hz.

[0035] In one embodiment of the present invention, in step (3), the wheat obtained in step (2) is subjected to differentiated tempering treatment according to the gluten properties of the wheat:

[0036] The conditioning process reasonably regulates the moisture distribution to ensure that the physical properties of the wheat grains meet the requirements of the subsequent powder cleaning and grinding processes. At the same time, combined with the different gluten strengths of wheat, high-frequency vibration waves are used to assist conditioning, so that moisture can quickly and evenly penetrate into the wheat grains, reduce the surface moisture retention time, and inhibit the growth of microorganisms.

[0037] In one embodiment of the present invention, in step (4), the wheat treated in step (3) is further cleaned, including thrashing, rotary vibrating screening, stone removal and color sorting. This process is used to remove impurities and unqualified particles remaining on the surface of the wheat, ensure that the wheat grains reach the expected cleanliness, and provide suitable raw materials for subsequent grinding.

[0038] In one embodiment of the present invention, in step (5), the wheat processed in step (4) is ground and sieved. The flour making process adopts a process flow of 6 skin mills (6 skins), 8 core mills (8 cores), 2 slag mills (2 slags), 2 tail mills (2 tails), 2 bran beaters (2 bran beaters) and 12 powder purifiers (12 powder purifiers).

[0039] In one embodiment of the present invention, in step (5), the 2B powder pipe of the skin grinding section and the 1M, 2M, 3M, and 4M powder pipes of the core grinding section are specifically selected to output powder, and the powder is mixed to obtain low-bacteria wheat flour.

[0040] In one embodiment of the present invention, in step (5), when the wheat is medium-high gluten wheat, the rolling distance parameter is:

[0041] Rolling distance of leather grinding section (section B): 1B: 0.48-0.50mm, 2B: 0.26-0.30mm, 3B: 0.16-0.18mm, 4B: 0.08-0.10mm, 5B: 0.02-0.03mm;

[0042] Rolling distance of core grinding section (M section): 1M: 0.018-0.020mm, 2M: 0.015-0.018mm, 3M: 0.014-0.016mm, 4M: 0.012-0.014mm;

[0043] Slag grinding section (S section) rolling distance: 1S: 0.020-0.024mm, 2S: 0.018-0.020mm;

[0044] Rolling distance of tail mill section (T section): 1T: 0.020-0.022mm.

[0045] In one embodiment of the present invention, in step (5), when the wheat is medium-high gluten wheat, the rolling distance parameters of the hull grinding section and the core grinding section are preferably:

[0046] Skin grinding segment 1B 0.48mm, 2B 0.28mm, 3B 0.17mm, 4B 0.08mm, 5B 0.03mm, core grinding segment 1M 0.018mm, 2M 0.016mm, 3M 0.014mm, 4M 0.013mm.

[0047] In one embodiment of the present invention, in step (5), when the wheat is low-gluten wheat, the rolling distance parameter is:

[0048] Rolling distance of leather grinding section (section B): 1B: 0.52-0.58mm, 2B: 0.30-0.35mm, 3B: 0.20-0.25mm, 4B: 0.10-0.15mm, 5B: 0.04-0.06mm;

[0049] Rolling distance of core grinding section (M section): 1M: 0.014-0.016mm, 2M: 0.012-0.014mm, 3M: 0.010-0.012mm, 4M: 0.008-0.010mm;

[0050] Slag grinding section (S section) rolling distance: 1S: 0.022-0.026mm, 2S: 0.020-0.024mm;

[0051] Rolling distance of tail mill section (T section): 1T: 0.022-0.026mm.

[0052] In one embodiment of the present invention, in step (5), when the wheat is low-gluten wheat, the rolling distance parameters of the hull grinding section and the core grinding section are preferably:

[0053] Skin grinding segment 1B 0.56mm, 2B 0.33mm, 3B 0.22mm, 4B 0.10mm, 5B 0.04mm, core grinding segment 1M 0.014mm, 2M 0.013mm, 3M 0.012mm, 4M 0.010mm.

[0054] In one embodiment of the present invention, the rolling distance of the hull grinding section of low-gluten wheat is slightly larger than that of medium- and high-gluten wheat to ensure the integrity of the endosperm and reduce excessive crushing; the rolling distance of the core grinding section is appropriately increased than that of medium- and high-gluten wheat to ensure the fineness and grading effect of the material.

[0055] In one embodiment of the present invention, during the grinding process, fine bran and dust in the mill feed are separated by a hopper suction system, while the temperature and humidity of the feed are reduced, thereby reducing the conditions for the growth of microorganisms during the grinding process.

[0056] In one embodiment of the present invention, the hopper suction system includes a suction device, an airflow duct, a dust collecting device and a control system; the suction device is installed on the top or side of the hopper, and the dust, bran and fine impurities are sucked away from the hopper by negative pressure suction. The suction volume of the suction device is 75-300m 3 / h; the air flow duct transports the inhaled air and impurities to the dust collecting device; the dust collecting device separates impurities through a multi-stage filtration system to keep the air inside the hopper clean.

[0057] In one embodiment of the present invention, the air suction volume of the hopper suction device is controlled at 75-300m 3 / h to ensure the cleanliness of the grinding environment and the stability of the quality of wheat flour.

[0058] In one embodiment of the present invention, in terms of the precision of the process design, the present invention also carries out a technical upgrade of the hopper suction system. By generating a negative pressure environment in the hopper area, dust, bran and fine particles are extracted in time, which not only prevents the accumulation of particles inside the equipment, but also effectively curbs the reproduction of microorganisms in the flour making process. This negative pressure suction technology is closely integrated with the entire flour making process, which not only ensures a clean production environment, but also enhances the working efficiency of the equipment and extends the service life of the equipment. The system complements the optimization of the powder cleaning process, so that each stage of the production process can minimize the microbial load, further ensuring the hygiene standards and quality stability of the finished flour.

[0059] In one embodiment of the present invention, in the powder cleaning stage, the mesh size and suction volume of the powder cleaning machine are adjusted according to the material particle size, and combined with the hopper suction device in the grinding stage, the low temperature and low humidity environment in the grinding chamber is maintained to finally obtain wheat flour.

[0060] In one embodiment of the present invention, the suction air volume of the powder purifier is 200-1000m 3 / h.

[0061] In one embodiment of the present invention, in step (5), the powder cleaning process is implemented by a four-stage screening system, which classifies large coarse particles, medium coarse particles, small coarse particles, and coarse powder respectively.

[0062] In one embodiment of the present invention, in step (5), the medium and coarse particles obtained during the grinding process are concentrated in a sieve number of 36W for screening and grading, and a sieve number of 54W for retention in screening and grading. The corresponding powder purifier is configured with a sieve number of less than 36 at the head end of the lower layer and a sieve number of more than 24 at the end of the lower layer.

[0063] In one embodiment of the present invention, the powder purifier adopts the model HFQFD.49x2x3-Ⅱ, and the screen aperture and air volume are adjusted according to the material particle size and moisture content during the powder purifying process. 1P1 lower layer front section screen number 24, rear end screen number 20; 2P3 lower layer front section screen number 36, rear end screen number 28; 6P lower layer front section screen number 46, rear end screen number 40.

[0064] In the flour making process of the present invention, the moisture content of wheat entering the mill directly affects the particle size distribution and physical properties of the material. The present invention significantly improves the material morphology in the grinding stage by precisely controlling the moisture content of the conditioning, especially operating under low moisture conditions. Low moisture conditioning can not only ensure that larger particles of material are obtained in subsequent grinding, thereby allowing the use of larger sieve holes and stronger air volume in the powder cleaning process, but also optimize the grading effect to ensure the effective separation of bran and endosperm. In addition, under low moisture conditions, the viscosity of the wheat endosperm layer during the grinding process is significantly weakened, avoiding the adhesion of materials in the pipeline, thereby greatly reducing the risk of microbial growth in the subsequent powder path. The synergistic effect of this series of complex parameters ensures the high cleanliness and stability of the production process. When a low amount of water is used in the conditioning process, the particle size of the material produced by subsequent grinding is often larger, because moisture has a significant plasticizing effect on the structure of wheat particles. Under low moisture conditions, the surface layer and endosperm of the wheat grains maintain a high hardness and toughness, are not easily over-crushed during grinding, and the particles produced are relatively large. On the contrary, a higher amount of water added will cause the surface and internal structure of the wheat to be over-softened, and the wheat will be easily broken into smaller particles during grinding, affecting the subsequent grading effect.

[0065] When the material particle size is large, using a larger screen aperture and stronger suction during the powder cleaning process can achieve more efficient material classification. Larger particles are easier to be physically separated through the screen, ensuring effective classification between bran and endosperm. Improved classification effect means that the bran and endosperm are separated more thoroughly, thereby reducing the possibility of bran impurities entering the finished flour. In addition, larger particles are also easier to be efficiently separated by strong suction, further improving the efficiency of the powder cleaning process.

[0066] The process of the present invention aims to significantly reduce the content of microorganisms in finished flour and improve the sanitary quality and safety of wheat flour by introducing pulsed electric field technology combined with comprehensive optimization of conditioning, grinding, powder cleaning and suction systems. The process includes the following steps:

[0067] (1) After the raw grain enters the warehouse, it is cleaned of impurities through a vibrating screen, a stone remover, and a thresher in turn, and a circulating suction system is used to remove surface impurities and microorganisms; (2) During the conditioning process, the wheat grains are treated by applying an electromagnetic field to inhibit the reproduction of microorganisms, and high-frequency vibration waves are used to assist in one or two conditioning processes to ensure that moisture evenly penetrates into the wheat grains. For medium-gluten and high-gluten wheat, two conditioning processes are used, with the first water addition accounting for 80% and the second water addition accounting for 20%, to avoid bran damage and further reduce the risk of microbial proliferation; (3) During the grinding process, the grinding roller parameters (including speed and rolling distance) are dynamically adjusted according to the gluten content and moisture content of the wheat to ensure that the particle size of the ground material is accurately controllable; (4) The powder cleaning process further optimizes the grading and separation effects of the material by precisely controlling the mesh size and suction volume of the screen, ensuring the efficient separation of bran and endosperm and reducing the conditions for the growth of microorganisms; (5) Finally, through the synergistic effect of hopper suction and grinding chamber suction, a low temperature and low humidity environment is maintained to further enhance the inhibition effect on microorganisms. This process not only improves the purity of wheat flour, but also achieves significant sterilization effect through moisture and particle size control throughout the entire process. It is suitable for the production of a variety of wheat flour products such as low-gluten, medium-gluten and high-gluten.

[0068] The present invention provides a low-bacteria wheat flour prepared based on the above processing technology.

[0069] The invention also provides application of the low-bacteria wheat flour in the processing of flour products.

[0070] [Beneficial Effects]

[0071] Compared with the existing low-bacteria wheat flour production technology, the present invention does not use any bactericides or chemical reagents in production. It relies on process improvements to achieve low-bacteria effects by controlling the microorganisms on the surface of wheat grains before grinding and strengthening the stripping effect of bran and endosperm during the flour making process, which meets the requirements of clean labels.

[0072] The present invention achieves process optimization in multiple key dimensions, especially in terms of microbial load management, product quality stability and production cost control, showing certain technical advantages. First, the present invention eliminates the dependence on chemical additives through precise physical regulation of the milling process, especially the systematic improvement of the conditioning and cleaning steps, thereby achieving microbial control while reducing the operational risks and additional cost expenditures associated with chemical substances.

[0073] Furthermore, the present invention has significant process adaptability and can maintain the relative stability of the production process without relying on variables such as the initial microbial load, particle distribution and moisture content in the raw materials. This operation mode independent of the raw material characteristics makes the process more flexible and can cope with a variety of complex working conditions in the actual production environment without frequent adjustment of operating parameters, ensuring product consistency and reducing the complexity of human intervention.

[0074] In terms of product quality improvement, the present invention achieves effective separation of bran and endosperm through careful optimization of the conditioning and powder cleaning processes, thereby reducing the activity of polyphenol oxidase (PPO), reducing the risk of flour browning, and ensuring that the color of the flour remains stable for a long time. At the same time, the efficient separation of bran also reduces the ash content in the finished product and improves the purity of the flour. The improvement of these quality indicators is achieved through physical means rather than relying on external chemical treatment, and is therefore more in line with the current environmental protection and health trends in food production.

[0075] In particular, during the conditioning process, the present invention adopts a technology of adding water in stages. By gradually penetrating water, it avoids excessive water absorption or rupture of the bran during the water addition process, ensures the uniform distribution of water in the wheat particles, and thus optimizes the processing performance of wheat in the subsequent milling process. This method of adding water not only enhances the stability of wheat during the milling process, but also makes moisture control more precise and reduces uncertainty in production. The alternating magnetic field is used to suppress the activity of microorganisms on the surface of wheat grains during conditioning, and the vibration wave-assisted conditioning system effectively reduces the reproduction of microorganisms during the conditioning process.

[0076] The powder cleaning process effectively reduces the probability of bran breakage through the optimization design of the screen aperture and the suction volume, thereby improving the purity and flour yield of the flour. The hopper suction system further ensures the cleanliness of the production environment and reduces the risk of dust accumulation and microbial growth. The application of this system makes the flour making process more stable, prolongs the service life of the equipment, and ensures the hygienic quality of the product.

[0077] In general, the present invention achieves control of multiple important parameters in wheat flour production through fine adjustment of physical processes, and significantly controls the microbial content of wheat flour without the addition and participation of any chemical reagents. The total colony count in the wheat flour processed after the wheat is treated is below 1000 CFU / g. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Figure 1 This is a trend chart showing the effects of different watering methods on the changes in microorganisms on the surface of wheat grains during conditioning. DETAILED DESCRIPTION

[0079] Based on the gaps in the prior art, the inventor of this case has proposed the present invention after long-term summary and continuous practice.

[0080] The technical solution, implementation process and principle of the present invention are further explained as follows.

[0081] The technical solution of the present invention is further described in detail below through several embodiments. However, the selected embodiments are only

[0082] It is used to illustrate the present invention but not to limit the scope of the present invention.

[0083] For the convenience of explanation, the powder purifiers involved in the sampling in the embodiments and comparative examples are two-pass powder purifiers, the front-middle pass and the rear-pass pass, and the wheat flour sampling point is a representative front-middle pass powder outlet point in the powder path.

[0084] Method for determination of microbial count: Determine the total colony count in wheat flour in accordance with GB 4789.2-2016.

[0085] Determination of ash content: using the incineration method, refer to GB / T 5505-2008.

[0086] Flour yield determination: After the wheat grains are tempered, they are ground in a test mill and the flour from each powder tube is collected. The weight of the flour is calculated as the percentage of the weight of the wheat grain raw material.

[0087] Determination of damaged starch content in wheat flour: The damaged starch content of flour was determined according to AACC method 76-33.01, using SDmatic French Chopin damaged starch tester, and the results were expressed as UCD values.

[0088] Example 1

[0089] (1) The purchased medium-gluten wheat is subjected to 360-degree dust removal in the grain unloading pit, initially screened through two high-efficiency rotary vibrating screens, and light impurities are removed using two circulating air suction systems before entering the original grain silo;

[0090] (2) the medium-gluten wheat after the initial cleaning in (1) is subjected to a multi-step cleaning process, including sequentially passing through a vibrating screen, circulating air suction, a stone remover, a thresher, passing through a vibrating screen, air suction, a stone remover, a thresher again, and finally being processed by a vibrating screen and circulating air suction, for a total of 3 screenings, 3 air suctions, 2 stone removals, and 2 threshers;

[0091] (3) The medium-gluten wheat cleaned in (2) is tempered by using sterile water and high-frequency vibration waves to assist the tempering for 16 hours at a working frequency of 190 Hz. The amount of water added is adjusted according to the moisture content of the raw grain so that the final moisture content of the wheat reaches 14.6%. During the entire tempering process, an alternating magnetic field treatment is applied in the wheat tempering bin with a magnetic field strength of 10 mT and a frequency of 30 Hz;

[0092] (4) cleaning the medium-gluten wheat after conditioning in (3), specifically, sequentially processing through a high-efficiency thresher → a rotary vibrating screen → a circulating air suction machine → a stone remover → a color sorter, and finally entering the grinding process;

[0093] (5) In the grinding process, the flour making process of 6 skins, 8 cores, 2 residues, 2 tails, 2 brans and 12 clean flour is adopted. After the materials are ground, classified, sifted and other processes, 1M-4M and 2B powder pipes are selected to discharge the powder, and the powder is mixed to obtain wheat flour. The air suction volume of the hopper is 300m 3 / h, the air volume of powder purifier 1 is 500m 3 / h, the mesh number of the lower first section is 36, the mesh number of the lower last section is 28; the air volume of the powder purifier 2 is 300m 3 / h, the mesh number of the lower head section is 46, and the mesh number of the lower end section is 40. The rolling distance parameters of the grinding rollers are: the skin grinding section 1B0.48mm, 2B 0.28mm, 3B 0.17mm, 4B 0.08mm, 5B 0.03mm, the core grinding section 1M 0.018mm, 2M 0.016mm, 3M0.014mm, 4M 0.013mm; the rolling distance of the slag grinding section: 1S: 0.022mm, 2S: 0.019mm; the rolling distance of the tail grinding section: 1T: 0.021mm.

[0094] Example 2

[0095] (1) The purchased low-gluten wheat is subjected to 360-degree vacuuming in the grain unloading pit, initially screened through two high-efficiency rotary vibrating screens, and light impurities are removed using two circulating air suction systems before entering the original grain silo;

[0096] (2) the low-gluten wheat after the initial cleaning in (1) is cleaned in multiple steps, including passing through a vibrating screen, circulating air suction, a stone remover, a thresher, passing through a vibrating screen, air suction, a stone remover, a thresher again, and finally passing through a vibrating screen and circulating air suction, for a total of 3 screenings, 3 air suctions, 2 stone removals, and 2 threshers;

[0097] (3) The low-gluten wheat cleaned in (2) is tempered by using sterile water and high-frequency vibration waves to assist the tempering for 6 hours at a working frequency of 190 Hz. The amount of water added is adjusted according to the moisture content of the raw grain so that the final moisture content of the wheat reaches 14.3%. During the entire tempering process, an alternating magnetic field treatment is applied in the wheat tempering bin with a magnetic field strength of 30 mT and a frequency of 50 Hz;

[0098] (4) cleaning the low-gluten wheat after conditioning in (3), specifically, sequentially processing the wheat through a high-efficiency thresher → a rotary vibrating screen → a circulating air suction machine → a stone remover → a color sorter, and finally entering the milling process;

[0099] (5) In the grinding process, the flour making process of 6 skins, 8 cores, 2 residues, 2 tails, 2 brans and 12 clean flour is adopted. After the materials are ground, classified, sifted and other processes, 1M-4M and 2B powder pipes are selected to discharge the powder, and the powder is mixed to obtain wheat flour. The air suction volume of the hopper is 300m 3 / h, the air volume of powder purifier 1 is 500m 3 / h, the mesh number of the lower first section is 36, the mesh number of the lower last section is 28; the air volume of the powder purifier 2 is 300m 3 / h, the mesh number of the lower head section is 46, and the mesh number of the lower end section is 40. The rolling distance parameters of the grinding rollers are: the skin grinding section 1B0.56mm, 2B 0.33mm, 3B 0.22mm, 4B 0.10mm, 5B 0.04mm, the core grinding section 1M 0.014mm, 2M 0.013mm, 3M0.012mm, 4M 0.010mm; the rolling distance of the slag grinding section: 1S: 0.022mm, 2S: 0.020mm; the rolling distance of the tail grinding section: 1T: 0.022mm.

[0100] Example 3

[0101] (1) The purchased high-gluten wheat is subjected to 360-degree vacuuming in the grain unloading pit, initially screened through two high-efficiency rotary vibrating screens, and light impurities are removed through two circulating air suction systems before entering the original grain silo;

[0102] (2) the high-gluten wheat after the initial cleaning in (1) is cleaned in multiple steps, including passing through a vibrating screen, circulating air suction, a stone remover, a thresher, passing through a vibrating screen, air suction, a stone remover, a thresher again, and finally passing through a vibrating screen and circulating air suction, for a total of 3 screenings, 3 air suctions, 2 stone removals, and 2 threshers;

[0103] (3) The high-gluten wheat after cleaning in (2) is tempered, firstly using sterile water and high-frequency vibration wave to assist tempering for 16 hours, with a water content of 80%, and then tempering by beating and watering for 6 hours, with a water content of 20%, so that the final moisture content of the wheat reaches 15.0%. During the entire tempering process, an alternating magnetic field treatment is applied in the wheat tempering bin, with a magnetic field intensity of 30 mT and a frequency of 50 Hz;

[0104] (4) cleaning the high-gluten wheat after conditioning in (3), specifically, sequentially processing the high-efficiency thresher → rotary vibrating screen → circulating air suction → stone remover → color sorter, and finally entering the grinding process;

[0105] (5) In the grinding process, a flour making process of 6 skins, 8 cores, 2 slags, 2 tails, 2 bran beatings and 12 purifying powders is adopted. After the materials are ground, classified, sieved and other processes, 1M-4M and 2B powder pipes are selected to discharge the powders, and the powders are mixed to obtain wheat flour, wherein the hopper suction volume is 300m3 / h, the powder purifier 1 air volume is 500m3 / h, the lower layer head section screen number is 36, and the lower layer end section screen number is 28; the powder purifier 2 air volume is 300m3 / h, the lower layer head section screen number is 46, and the lower layer end section screen number is 40. The grinding roller rolling parameters refer to Example 1.

[0106] Example 4

[0107] (1) The purchased medium-gluten wheat is subjected to 360-degree dust removal in the grain unloading pit, initially screened through two high-efficiency rotary vibrating screens, and light impurities are removed using two circulating air suction systems before entering the original grain silo;

[0108] (2) the medium-gluten wheat after the initial cleaning in (1) is subjected to a multi-step cleaning process, including sequentially passing through a vibrating screen, circulating air suction, a stone remover, a thresher, passing through a vibrating screen, air suction, a stone remover, a thresher again, and finally being processed by a vibrating screen and circulating air suction, for a total of 3 screenings, 3 air suctions, 2 stone removals, and 2 threshers;

[0109] (3) The medium-gluten wheat after cleaning in (2) is tempered, firstly using sterile water and high-frequency vibration wave to assist tempering for 10 hours, with a water content of 80%, and then tempering by beating and watering for 6 hours, with a water content of 20%, so that the final moisture content of the wheat reaches 14.6%. During the entire tempering process, an alternating magnetic field treatment is applied in the wheat tempering bin, with a magnetic field intensity of 30 mT and a frequency of 50 Hz;

[0110] (4) cleaning the medium-gluten wheat after conditioning in (3), specifically, sequentially processing through a high-efficiency thresher → a rotary vibrating screen → a circulating air suction machine → a stone remover → a color sorter, and finally entering the grinding process;

[0111] (5) In the grinding process, a flour making process of 6 skins, 8 cores, 2 slags, 2 tails, 2 bran beatings and 12 purifying powders is adopted. After the materials are ground, classified, sieved and other processes, 1M-4M and 2B powder pipes are selected to discharge the powders, and the powders are mixed to obtain wheat flour, wherein the hopper suction volume is 300m3 / h, the powder purifier 1 air volume is 500m3 / h, the lower layer head section screen number is 36, and the lower layer end section screen number is 28; the powder purifier 2 air volume is 300m3 / h, the lower layer head section screen number is 46, and the lower layer end section screen number is 40. The grinding roller rolling parameters refer to Example 1.

[0112] Example 5

[0113] Referring to Example 4, the only difference is that in step (3), during the entire tempering process, an alternating magnetic field is applied in the wheat silo, the magnetic field strength is 10 mT, the frequency is 50 Hz, and the air volume of the powder purifier 1 in (5) is 200 m3 / h, and the air volume of the powder purifier 2 is 100 m3 / h. 3 / h.

[0114] Example 6

[0115] Referring to Example 4, the only difference is that in step (3), an alternating magnetic field is applied in the wheat tempering bin during the entire tempering process, the magnetic field strength is 30 mT, and the frequency is 20 Hz. In step (5), the mesh number of the lower head section of the powder purifier 1 is 40, and the mesh number of the lower end section is 32; the mesh number of the lower head section of the powder purifier 2 is 50, and the mesh number of the lower end section is 44.

[0116] Example 7

[0117] Refer to Example 4, the only difference is that in step (3), during the entire tempering process, an alternating magnetic field is applied in the wheat tempering bin, the magnetic field strength is 50 mT, the frequency is 50 Hz, and the hopper suction volume in step (5) is 75 m 3 / h.

[0118] Comparative Example 1

[0119] Referring to Example 1, the only difference is that the alternating magnetic field treatment is not applied during the conditioning process. The other aspects remain unchanged to obtain the corresponding wheat flour product.

[0120] Comparative Example 2

[0121] Referring to Example 1, the only difference is that the dampening method in step (3) is replaced by dampening with a beating plate instead of high-frequency vibration wave assisted conditioning, and the conditioning time is 26 hours. The other conditions remain unchanged to obtain the corresponding wheat flour product.

[0122] Comparative Example 3

[0123] Referring to Example 1, the only difference is that the roller spacing parameters of the skin grinding section and the core grinding section are: skin grinding section 1B 0.44mm, 2B 0.24mm, 3B 0.13mm, 4B 0.06mm, 5B 0.02mm, core grinding section 1M 0.014mm, 2M 0.012mm, 3M 0.01mm, 4M 0.009mm. Others remain unchanged to obtain the corresponding wheat flour product.

[0124] Comparative Example 4

[0125] Referring to Example 1, the only difference is that the roller spacing parameters of the skin grinding section and the core grinding section are: skin grinding section 1B 0.52mm, 2B 0.30mm, 3B 0.16mm, 4B 0.09mm, 5B 0.04mm, core grinding section 1M 0.018mm, 2M 0.012mm, 3M 0.013mm, 4M 0.0120mm. Others remain unchanged to obtain the corresponding wheat flour product.

[0126] Comparative Example 5

[0127] Referring to Example 1, the only difference is that the grinding roller spacing parameters of the skin grinding section and the core grinding section are: skin grinding section 1B 0.54mm, 2B 0.32mm, 3B 0.19mm, 4B 0.09mm, 5B 0.04mm, core grinding section 1M 0.018mm, 2M 0.012mm, 3M0.013mm, 4M 0.0120mm. Others remain unchanged to obtain the corresponding wheat flour product.

[0128] The microbial content of the wheat flour products and intermediate materials obtained in each embodiment and comparative example was measured, and the results are shown in Table 1.

[0129] Table 1. Microbial content of wheat flour and intermediate materials in various examples and comparative examples

[0130]

[0131]

[0132] “—” means not detected.

[0133] Example 8

[0134] Another batch of low-gluten wheat was selected, and the conditioning step in step (2) was adjusted with reference to Example 2. Other conditions remained unchanged, and the microbial content on the surface of the obtained grains and the quality characteristics of the flour after the test mill were measured.

[0135] The test was performed three times in parallel and the average value was calculated. The results are shown in Table 2.

[0136] Table 2. Effects of conditioning methods on the changes in microorganisms on the surface of low-gluten wheat grains during conditioning and the quality characteristics of wheat flour after milling

[0137]

[0138] Note: "Tempering time is 0h" refers to wheat grains that are taken out immediately after water treatment and are not stored in a wheat bin; "dry wheat" refers to wheat grains that have not been water treated.

[0139] Example 9

[0140] Another batch of medium-gluten wheat was selected, and the conditioning step in step (2) was adjusted with reference to Example 1. Other conditions remained unchanged, and the content of microorganisms on the surface of the obtained grains was measured. The obtained wheat grains were ground with a test mill and the flour yield and ash content were measured.

[0141] The test was performed three times in parallel and the average value was calculated. The results are shown in Table 3.

[0142] Table 3. Effects of conditioning methods on the changes in microorganisms on the surface of medium-gluten wheat grains during conditioning and the quality characteristics of wheat flour after milling

[0143]

[0144] Example 10

[0145] Another batch of high-gluten wheat was selected, and the conditioning step in step (2) was adjusted with reference to Example 3. Other conditions remained unchanged, and the microbial content on the surface of the obtained grains was measured.

[0146] The test was performed three times in parallel and the average value was calculated. The results are shown in Table 4.

[0147] Table 4. Effects of conditioning methods on the changes in microorganisms on the surface of high-gluten wheat grains during conditioning and the quality characteristics of wheat flour after milling

[0148]

[0149]

[0150] Embodiment 11

[0151] Referring to Example 1, the air suction volume of the hopper in the grinding step in step (5) was adjusted, and other conditions remained unchanged, and the microbial content on the surface of the obtained grains was measured. The results are shown in Table 5.

[0152] Table 5. Effect of hopper suction on microorganisms of materials during grinding (CFU / g)

[0153]

[0154] Effect analysis:

[0155] Combined with Example 1 and Comparative Examples 3-5, the parameters of the grinding rollers, especially the parameters of the front skin grinding rollers and the core grinding rollers, have a significant effect on the wheat flour microorganisms. A specific grinding roller spacing will significantly increase the bacterial content of the wheat flour. This may be because a grinding roller spacing that is too small will result in a greater scraping effect on the bran, causing some bran to be broken and mixed into the flour, increasing the fine bran debris in the subsequent materials, increasing the difficulty of subsequent material classification, and increasing the ash content and microbial content of the wheat flour. At the same time, a grinding roller spacing that is too small will also increase the damaged starch content of the wheat flour. The specific results are shown in Table 6:

[0156] Table 6

[0157] Sample name Ash UCD Example 1 0.48 23.4 Comparative Example 3 0.53 26.8

[0158] However, if the spacing between the grinding rollers is too large, the grinding rollers will have poor scraping effect on the bran and poor endosperm crushing effect, resulting in a low flour yield; at the same time, it will affect the particle size of the wheat flour. If the particle size of the wheat flour is too large, the quality of the noodle products may be affected.

[0159] Further,

[0160] Combining the data of Examples 1-3, Examples 8-10, Comparative Example 2 and Tables 1-4, it can be concluded that the watering method has a crucial influence on inhibiting the growth of microorganisms on the surface of wheat grains during the conditioning process, and also has a significant effect on reducing the wheat tempering time. Especially for high-gluten wheat grains, when the plate-beating watering process is adopted, the microbial growth rate is significantly higher than that of wheat grains using the high-frequency vibration wave-assisted conditioning process. This phenomenon shows that the high-frequency vibration wave-assisted conditioning process has obvious advantages, which can significantly shorten the time required for conditioning and accelerate the migration of water to the inside of the wheat grains, thereby reducing the retention of surface moisture and inhibiting the growth of microorganisms. In addition, at the same time, the flour yield and ash content of wheat tempered with the assistance of high-frequency vibration waves are better than those of conventional plate-beating water-treated wheat, which can ensure the sanitary quality and stability of the flour while effectively improving the physical properties and processing performance of the product.

[0161] The advantages of high-frequency vibration wave assisted conditioning can be understood from two key aspects: First, the mechanical disturbance effect brought by vibration can accelerate the uniform distribution of water on the surface of wheat, reduce the excessive accumulation of local water, and thus prevent the rapid reproduction of microorganisms under these favorable conditions. Second, vibration accelerates the dynamic process of water penetration, allowing water to migrate faster to the inside of the wheat grain, reducing the surface water retention time, and thus effectively reducing the growth rate of surface microorganisms.

[0162] Further analysis of the performance of different varieties of wheat during the conditioning process revealed that within the same conditioning time, the growth rate of microorganisms on the surface of wheat grains showed significant varietal differences: low-gluten wheat < medium-gluten wheat < high-gluten wheat. This phenomenon can be attributed to the differences in water requirements of different varieties of wheat during conditioning. Low-gluten wheat has a lower water requirement before milling, and the amount of water added is correspondingly less, so the retention time of moisture on its surface is shorter, which is not conducive to the growth and reproduction of microorganisms. For medium-gluten and high-gluten wheat, due to their higher water requirement before milling, the amount of water added during the hydration process is relatively large, and the rate at which moisture on the surface of the grains migrates to the interior is relatively slow, resulting in the surface moisture being maintained at conditions suitable for microbial growth for a long time.

[0163] Combined with the data of Examples 1-7 and Comparative Example 1, applying an alternating magnetic field during the modulation process can effectively inhibit the reproduction of microorganisms during the modulation process. The ideal parameters for microbial inhibition are a magnetic field intensity of 30-50 mt and a magnetic field frequency of 50 Hz. Too high a magnetic field intensity or frequency has no obvious inhibitory effect on microorganisms, but may have an adverse effect on the quality of flour. At the same time, combined with the high-frequency vibration conditioning method, the inhibitory effect of the electromagnetic field on microbial reproduction is more obvious under the condition of low water activity.

[0164] Combined with the data analysis of Example 4, Example 7 and Table 5, the hopper suction system has a significant impact on the microbial content in the grinding chamber material and the final flour output. Specifically, with the increase in the suction volume, the microbial content in the material shows a significant downward trend. This phenomenon shows that a larger suction volume can not only more effectively remove large particles of dust and bran in the material, but also fundamentally destroy the conditions for microbial growth by taking away part of the moisture in the material and reducing the temperature in the grinding chamber.

[0165] It can be clearly seen from the trend of microbial changes in the feed roller material that as the hopper suction volume increases, the number of microorganisms in the incoming material gradually decreases, which shows that the negative pressure of the suction system has a positive effect on the inhibition of microorganisms on the surface of the material. Especially for the lower grinding chamber material, the suction volume reaches 300m 3 / h, the number of microorganisms in the material is significantly reduced compared with the material on the feed roller. However, when the suction volume is reduced, the number of microorganisms in the lower grinding chamber material gradually approaches or even exceeds that in the feed roller material. This phenomenon reveals that the key role of the suction system is not limited to surface particle cleaning, but also includes intervention in the microbial ecology of the entire system.

[0166] This significant change trend can be attributed to the synergistic effect of the grinding chamber suction and the hopper suction system. The negative pressure generated by the grinding chamber suction alone has limited dust suction capacity and it is difficult to effectively discharge the air containing dust and microorganisms to the Shakron. Although the negative pressure inside the grinding chamber can slow down the accumulation of microorganisms to a certain extent, it is not strong enough to completely remove the microbial carriers in the dust. Through the organic combination with the hopper suction system, the two form a complete airflow channel to ensure the complete removal of dust and microbial carriers. Therefore, the hopper suction system not only strengthens the negative pressure effect in the grinding chamber, but also achieves efficient dust removal, cooling and microbial inhibition by enhancing air flow.

[0167] From the comparison between Example 1 and Example 4, it can be seen that the conditioning conditions have an important influence on the material classification effect in the subsequent flour making process and the separation effect of the bran in the flour making process. The separation effect of the wheat powder purifier after the second watering is better than that of the wheat after the first watering. This is because the internal moisture distribution of the wheat grains after the second watering is more uniform. At the same time, the wheat grains are tempered with the assistance of high-frequency vibration waves and then watered by beating plates, which can increase the speed of moisture migration and reduce the retention time of moisture on the surface of wheat grains, so that the microbial reproduction rate in the conditioning process after the second beating plate watering is greatly reduced. At the same time, the bran surface is tougher after the second watering, and it is not easy to break into finer fragments during grinding, so that wheat can maintain the toughness of bran at a lower amount of water. At the same time, the synergistic effect of such a modulation method and a certain grinding roller rolling distance makes the particle size of the material after grinding larger, and with the specific powder purifier screen configuration, the grading effect of the powder purifier is greatly enhanced. The low-bacteria effect of the finished powder is ensured.

[0168] The embodiments provided above are not intended to limit the scope of the present invention, and the steps described are not intended to limit the execution order thereof. Those skilled in the art may make obvious improvements to the present invention in combination with existing common knowledge, which also fall within the scope of protection defined by the claims of the present invention.

Claims

1. A processing technology for low-bacteria wheat flour, characterized in that: The steps include: (1) Primary cleaning: The wheat is vacuumed and then screened using a rotary vibrating screen, and a circulating air suction system is used to remove light impurities to obtain primary cleaned wheat; (2) cleaning the raw wheat: subjecting the pre-cleaned wheat obtained in step (1) to screening, air suction, stone removal, and threshing to obtain cleaned wheat; (3) Tempering treatment: adding sterile water to the cleaned wheat obtained in step (2), using high-frequency vibration waves to assist in tempering, and applying an alternating magnetic field treatment in the tempering bin to obtain tempered wheat; (4) Cleaning the wheat: The wheat after conditioning obtained in step (3) is processed in sequence by a high-efficiency thresher → a rotary vibrating screen → a circulating air suction machine → a stone remover → a color sorter to obtain wheat to be ground into flour; (5) Flour making: the wheat to be ground obtained in step (4) is subjected to a flour making process of grinding, beating the bran and cleaning the flour, wherein the flour grinding includes a husk grinding section, a core grinding section, a slag grinding section and a tail grinding section, and the husk grinding section and the core grinding section are selected to discharge flour through a powder pipe, and the flour is mixed to obtain low-bacteria wheat flour; When the wheat is medium or high gluten wheat, the rolling distance parameters of the skin grinding section are: 1B: 0.48-0.50mm, 2B: 0.26-0.30mm, 3B: 0.16-0.18mm, 4B: 0.08-0.10mm, 5B: 0.02-0.03mm; the rolling distance of the core grinding section is: 1M: 0.018-0.020mm, 2M: 0.015-0.018mm, 3M: 0.014-0.016mm, 4M: 0.012-0.014mm; When wheat is low-gluten wheat, the rolling distance parameters of the skin grinding section are: 1B: 0.52-0.58mm, 2B: 0.30-0.35mm, 3B: 0.20-0.25mm, 4B: 0.10-0.15mm, 5B: 0.04-0.06mm; the rolling distance parameters of the core grinding section are: 1M: 0.014-0.016mm, 2M: 0.012-0.014mm, 3M: 0.010-0.012mm, 4M: 0.008-0.010mm.

2. The processing technology according to claim 1, characterized in that: In the step (3), Low-gluten wheat is tempered with high-frequency vibration waves for 6-8 hours; Medium-gluten wheat is tempered with high-frequency vibration waves for 8-12 hours; or tempered with high-frequency vibration waves and then tempered with water for 6 hours by beating the board; After high-gluten wheat is tempered with the aid of high-frequency vibration waves for 14-18 hours, it is tempered again for 6 hours by beating and watering.

3. The processing technology according to claim 2, characterized in that: During the secondary conditioning process, the first water addition accounts for 80% and is completed through the high-frequency vibration wave system; the second water addition accounts for 20% and is completed through the plate watering.

4. The processing technology according to claim 1, characterized in that: In the step (3), the electromagnetic field strength during the alternating magnetic field treatment is 1-50 mT and the frequency is 20-100 Hz.

5. The processing technology according to claim 1, characterized in that: In the step (3), after conditioning, the moisture content of the low-gluten wheat reaches 14.3±0.2%, the moisture content of the medium-gluten wheat reaches 14.6±0.2%, and the moisture content of the high-gluten wheat reaches 15.0±0.2%.

6. The processing technology according to claim 1, characterized in that: In the step (5), a flour-making process is adopted which includes 6 skin mills, 8 core mills, 2 slag mills, 2 tail mills, 2 bran beaters and 12 flour purifiers.

7. The processing technology according to claim 1, characterized in that: In the step (5), the 2B powder pipe of the skin grinding section and the 1M, 2M, 3M and 4M powder pipes of the core grinding section are specifically selected to output powder, and the powder is mixed to obtain low-bacteria wheat flour.

8. The processing technology according to claim 1, characterized in that: In the step (5), When the wheat is medium-high gluten wheat, the rolling distance parameters are: rolling distance of the skin grinding section 1B: 0.48-0.50mm, 2B: 0.26-0.30mm, 3B: 0.16-0.18mm, 4B: 0.08-0.10mm, 5B: 0.02-0.03mm; rolling distance of the core grinding section 1M: 0.018-0.020mm, 2M: 0.015-0.018mm, 3M: 0.014-0.016mm, 4M: 0.012-0.014mm; rolling distance of the slag grinding section 1S: 0.020-0.024mm, 2S: 0.018-0.020mm; rolling distance of the tail grinding section 1T: 0.020-0.022mm; When the wheat is low-gluten wheat, the rolling distance parameters are: rolling distance of skin grinding section 1B: 0.52-0.58mm, 2B: 0.30-0.35mm, 3B: 0.20-0.25mm, 4B: 0.10-0.15mm, 5B: 0.04-0.06mm; rolling distance of core grinding section 1M: 0.014-0.016mm, 2M: 0.012-0.014mm, 3M: 0.010-0.012mm, 4M: 0.008-0.010mm; rolling distance of slag grinding section 1S: 0.022-0.026mm, 2S: 0.020-0.024mm; rolling distance of tail grinding section 1T: 0.022-0.026mm.

9. Low-bacteria wheat flour obtained by the processing technology according to any one of claims 1 to 8.

10. Use of the low-bacteria wheat flour according to claim 9 in the processing of flour products.

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