CN112167337B - Ultraviolet sterilization method and sterilization machine for producing high-activity liquid milk - Google Patents

Abstract

The invention discloses an ultraviolet sterilization method and a sterilization machine for producing highly active liquid milk, and belongs to the technical field of food processing. The ultraviolet sterilizer of the present invention has ultraviolet sterilization components 15, feed pump 8, console 9, lamp holder 10, ultraviolet lamp bracket 11, shell bracket 12, stainless steel shell 13, partition 14, diverter 16, heating The tube 17 and the UV sterilization component 15 include a gasket 1, a UV intensity monitor 2, a three-way valve 3, a PFA tube 4, a UV lamp 5, a quartz sleeve 6, and a PFA tube fixing clip 7. The present invention adopts the spiral surrounding form of PFA tube 4 and controls the D/Dc range to 0.03-0.1, changes the liquid milk flow rate or the length of milk running in the PFA tube 4, and changes the number of parallel ultraviolet lamp tubes to change the quality of milk. Large processing capacity, easy operation, less time consuming, can meet a variety of processing requirements, and is widely used.

Description

Ultraviolet sterilization method and sterilization machine for producing highly active liquid milk

Technical field

The invention relates to an ultraviolet sterilization method and a sterilizer for producing highly active liquid milk, and belongs to the technical field of food processing.

Background technique

Ultraviolet sterilization is a new type of non-thermal sterilization method. The ultraviolet (UV-C) band used for sterilization is usually 200-280nm, with 253.7nm being the best. UV rays kill bacteria, viruses, fungi and other microorganisms by damaging their DNA and preventing them from multiplying. Ultraviolet sterilization is mainly used in three areas: air sterilization, liquid sterilization and surface sterilization. In the food industry, for liquid sterilization, clarified liquids such as water, egg liquid, juice, and alcohol have been used. Since ultraviolet light has weak penetration into turbid liquids, the materials currently available for ultraviolet sterilization are mainly limited to clear liquids.

Milk is rich in nutrients and plays an important role in human growth and health. Milk is rich in protein, vitamins, minerals, etc. In addition, milk is rich in biologically active proteins, including immune proteins and antibacterial enzymes. These active proteins play a protective role in human intestinal health and immune system. Most of these bioactive proteins are heat-sensitive proteins and are easily inactivated during the heat sterilization process of milk. Therefore, UV sterilization, as a relatively mature non-thermal sterilization technology, has good application prospects in milk sterilization. Although ultraviolet sterilization has low temperature and high efficiency, due to the high turbidity of milk, the ultraviolet penetration rate is reduced and the sterilization effect is greatly weakened.

At present, researchers have invented several ultraviolet sterilization methods and devices for different liquid foods. Sun Yijun (201811149112.8) disclosed a water-based ultraviolet sterilization method, which uses internal irradiation sterilization of water pipes and uses a ladder-shaped sterilization channel, which increases the ultraviolet treatment time of the water flow and improves the ultraviolet sterilization efficiency; however, since milk is a turbid liquid, although the ladder The shaped channel can have a certain diversion effect, but the UV lamps are at both ends of the device, and the uneven exposure of the milk to UV rays cannot guarantee the sterilization effect. Lin Daxiong (201680016968.0) disclosed a UV-C water purification equipment, which improved the UV-C LED module, reduced the loss of ultraviolet light during propagation, and improved the light extraction efficiency; however, the material container is a water tank, and the UV-C module Installed in the water tank, the material depth is large and in a static state, and the sterilization process is discontinuous. Sun Fukuan (201220341807.8) disclosed an ultraviolet beverage sterilization device. The device is mainly composed of a container for holding beverages and an internal ultraviolet lamp. Materials enter from the top of the container and flow out from the bottom; a microwave generator is used to generate microwaves to excite ultraviolet rays, which improves the The ultraviolet intensity and sterilization effect are improved, and the service life of the ultraviolet lamp is extended; however, due to the large peripheral space of the ultraviolet lamp in the container, the liquid layer is thick when the material flows in the container, and it is difficult for ultraviolet rays to fully penetrate the turbid liquid; and the material is perpendicular to The inflow and outflow direction of the UV lamp is perpendicular to the direction of the UV lamp, and it is difficult to control the flow pattern of the liquid during flow; therefore, this device cannot ensure that turbid materials are evenly irradiated by UV rays. Yin Quanquan (201720671599.0) disclosed an ultraviolet sterilizer for beverage production. The long cylinder is equipped with multiple ultraviolet lamps and is perpendicular to the direction of the cavity. The material inlet and outlet are at the top of the cavity; due to the inside of the cylinder The space is large and there is no drainage device, so it is difficult to control the material flow state; there are many UV lamps in the cylinder, and the actual UV dose received by the material is difficult to calculate. Ma Xuewu (201710865815.X) disclosed an ultraviolet sterilization device for donkey milk processing, including a sterilization box and a storage box. The sterilization box adopts thermal sterilization, and the ultraviolet lamp tube is installed in the storage box. During thermal sterilization, if the temperature of the sterilization box exceeds the set value, that is, when the sterilization box fails, the donkey milk in the sterilization box will automatically be discharged into the storage box, and the donkey milk will be continuously sterilized by ultraviolet rays; in this device UV only plays a backup and auxiliary role in sterilization, and the materials in the storage box are in uneven contact with the UV lamp, so the sterilization efficiency is very low.

From the above, it can be seen that the existing ultraviolet sterilization methods and equipment for liquid food are not suitable for milk sterilization. Therefore, there is an urgent need for an ultraviolet sterilization method that can sterilize milk, a turbid liquid, and retain active ingredients. It has excellent sterilization effect, can be processed continuously, and has an adjustable ultraviolet sterilization device with adjustable ultraviolet dosage, output, and processing temperature.

Contents of the invention

In order to solve at least one of the above problems, the present invention provides an ultraviolet sterilization method and sterilization machine for producing highly active liquid milk.

The first object of the present invention is to provide an ultraviolet sterilizer for producing highly active liquid milk. The ultraviolet sterilizer includes an ultraviolet sterilization component 15. The ultraviolet sterilization component 15 includes a gasket 1, an ultraviolet intensity monitor 2, and three Pass valve 3, PFA tube 4, UV lamp tube 5, quartz sleeve 6, PFA tube fixing clip 7, among which the surface of UV lamp 5 is covered with quartz sleeve 6, PFA tube 4 is tightly wound around the quartz sleeve 6, PFA The tube is fixed by the PFA tube fixing clip 7. There is no gap between the PFA tube 4 and the quartz sleeve 6. Every 1m (10-30 turns) of the PFA tube 4 is used as a sterilization area, and the PFA tube 4 in the adjacent sterilization area uses a tee. Valve 3 is connected; there is a gasket 1 between the UV lamp 5 and the quartz sleeve 6; the UV intensity detector 2 is close to the outside of the quartz sleeve 6 where the PFA tube is not wrapped.

In one embodiment of the present invention, one or more ultraviolet intensity detectors 2 are included between adjacent sterilization areas in the ultraviolet sterilizer.

In one embodiment of the present invention, the ultraviolet sterilizer is equipped with a feed pump 8 on one side, one end of the PFA pipe 4 passes through the feed pump 8, and the liquid milk is sent into the pipeline through the feed pump 8.

In one embodiment of the present invention, the ultraviolet sterilizer is equipped with a feed pump 8 on one side and a control panel 9 on the other side.

In one embodiment of the present invention, the ultraviolet sterilizer also includes a lamp holder 10 and an ultraviolet lamp bracket 11 . The lamp holder 10 and the ultraviolet lamp bracket 11 are used to fix the ultraviolet lamp 5 .

In one embodiment of the present invention, the ultraviolet sterilizer also includes a shell bracket 12 and a stainless steel shell 13; the stainless steel shell 13 is supported by the shell bracket 12; the stainless steel shell 13 contains a plurality of ultraviolet lamp tubes 5.

In one embodiment of the present invention, the ultraviolet sterilizer also includes a partition 14. The partition 14 separates each ultraviolet lamp tube 5 to ensure that the ultraviolet light emitted by different lamp tubes does not interfere with each other.

In one embodiment of the present invention, the ultraviolet sterilizer also includes a flow divider 16, which is between the feed pump 8 and the stainless steel shell 13; the flow divider 16 evenly distributes the raw materials to each cell according to the flow rate. 4 PFA tubes.

In one embodiment of the present invention, the ultraviolet sterilizer also includes a heating tube 17. The heating tube 17 is around the PFA pipe 4 between the feed pump 8 and the stainless steel shell 13, and is used to heat the material to a certain temperature. temperature for subsequent UV sterilization.

In one embodiment of the present invention, the number of ultraviolet sterilization components 15 in the ultraviolet sterilization device can be 1-100, and accordingly, the number of heating tubes 17 and diverters 16 can be 1-10; when the ultraviolet sterilization components When multiple units are placed in parallel, the processing capacity of the UV sterilizer can be 3-1200L/h.

In one embodiment of the present invention, the ultraviolet sterilizer also includes a console 9, which can control the ultraviolet lamp 5, the ultraviolet intensity monitor 2, the feed pump 8, the heating tube 17 and the stainless steel temperature inside the housing 13, and displays the UV intensity monitored by each UV intensity monitor.

In one embodiment of the present invention, the ultraviolet sterilization machine includes an ultraviolet sterilization component 15, a feed pump 8, a console 9, a lamp holder 10, an ultraviolet lamp bracket 11, a shell bracket 12, a stainless steel shell 13, Partition 14, diverter 16, heating tube 17, UV sterilization component 15 includes gasket 1, UV intensity monitor 2, three-way valve 3, PFA tube 4, UV lamp 5, quartz sleeve 6, PFA tube fixing clip 7; Among them, the stainless steel shell 13 is supported by the shell bracket 12; the stainless steel shell 13 contains a plurality of ultraviolet lamp tubes 5, the plurality of ultraviolet lamp tubes 5 are separated by partitions 14, and the ultraviolet lamp tubes 5 are fixed by a lamp tube holder. 10 is fixed to the UV lamp bracket 11; the surface of the UV lamp tube 5 is covered with a quartz sleeve 6, there is a layer of gasket 1 between the UV lamp 5 and the quartz sleeve 6, and the PFA tube 4 is tightly wound around the quartz sleeve 6. There is no gap between the tube 4 and the quartz sleeve 6. The PFA tube 4 is wound 10-30 times as a sterilization area. The entire sterilization area is fixed by the PFA tube fixing clip 7. The PFA tube 4 in the adjacent sterilization area is connected with a three-way valve 3. ; The ultraviolet intensity detector 2 is closely attached to the outside of the quartz sleeve 6 where the PFA tube is not wrapped; one side of the ultraviolet sterilizer is equipped with a feed pump 8 and the other side is equipped with a console 9; the feed pump 8 and stainless steel There is a heating pipe 17 around the PFA tube 4 between the housings 13; the flow divider 16 is between the feed pump 8 and the stainless steel housing 13.

In one embodiment of the present invention, the outer diameter of the quartz sleeve 6 is 2-3 cm, preferably 2.3 cm, and is supported and fixed by two stainless steel brackets to ensure that the ultraviolet lamp tube and the quartz sleeve are coaxial.

In one embodiment of the present invention, during operation, the liquid milk enters one end of the PFA tube 4 through the feed pump 8, and the liquid milk flows around the tube for several weeks, and then passes through the other end of the PFA tube 4 after being irradiated by ultraviolet light. To flow out, by controlling the opening and closing of the three-way valve 3, the flow direction of the liquid milk in the PFA tube 4 can be changed, allowing the liquid milk to enter the next area to continue UV sterilization, or to end the sterilization and flow out directly.

In one embodiment of the present invention, the stainless steel shell 13 is strictly sealed and equipped with a temperature control system inside. The temperature of the ultraviolet sterilization module can be controlled between 0-80°C through a water bath.

In one embodiment of the present invention, there are multiple metal slots inside the stainless steel shell 13, which can fix the PFA tube 4 wrapped around the quartz sleeve.

In one embodiment of the present invention, the specifications of the PFA pipe 4 are: inner diameter is 1-2mm, outer diameter is 2-3mm; further preferably: 1mm*2mm, 1.5mm*2mm or 2mm*3mm (inner diameter×outer diameter ).

In one embodiment of the present invention, the ratio of the surrounding inner diameter Dc of the PFA tube 4 to the inner diameter D of the PFA tube 4 in the ultraviolet sterilization device is between 0.03-0.1, ensuring that the liquid milk can be evenly distributed in the tube at different flow rates. Mixing, so that the liquid milk has good UV sterilization effect under different treatment amounts.

The second object of the present invention is to provide a method for producing highly active liquid milk using the sterilizer of the present invention.

In one embodiment of the present invention, the specifications of the PFA tube 4 in the sterilizer are: inner diameter is 1-2mm, outer diameter is 2-3mm; further preferably: 1mm*2mm, 1.5mm*2mm or 2mm*3mm (inner diameter × outer diameter).

In one embodiment of the present invention, the liquid milk is cow's milk or goat's milk.

In one embodiment of the present invention, the ratio of the surrounding inner diameter Dc of the PFA tube 4 to the inner diameter D of the PFA tube 4 in the ultraviolet sterilization device is between 0.03-0.1, ensuring that the liquid milk can be evenly distributed in the tube at different flow rates. Mixing, so that the liquid emulsion has good UV sterilization effect under different treatment amounts; calculate the Reynolds number (R _e ) and Dean number (D _e ) according to the following formula (1) and formula (2):

Among them, ρ is the density of liquid emulsion, which is 1021.46kg/m ² ; μ is the dynamic viscosity of liquid emulsion, which is 1.941×10 ³ Ns/m ² ; v is the flow rate of liquid emulsion in the tube; D is the inner diameter of PFA tube 4; Dc 4 surround the inner diameter of the PFA tube.

Re<2100 indicates that the liquid flow state is laminar flow, Re>4000 indicates that the liquid flow state is turbulent flow, and Re is between the two, indicating a mixed flow state. De is a representation of the way fluid flows in the coil. When 0.03<D/Dc<0.1, the fluid in the coil produces secondary flow pockets, which can enhance the degree of fluid mixing.

In one embodiment of the present invention, by changing the liquid milk flow rate or the length of the actually used PFA tube 4, the UV dose of the liquid milk is changed, so that the microorganisms in the liquid milk can meet the pasteurization requirements, and ensure that the microorganisms in the liquid milk can be pasteurized. There is no significant decrease in active protein; by changing the number of ultraviolet lamps connected in parallel, the processing capacity can be changed.

In one embodiment of the present invention, the highly active liquid milk refers to a certain sterilization method, and the limit of microorganisms in the liquid milk complies with the national standards for pasteurized milk (GB 19645-2010, GB 19301-2010), and can be used as pasteurized milk. Pasteurized milk is stored and sold, and is a liquid milk with a higher content of biologically active proteins such as immunoactive proteins and antibacterial enzymes.

In one embodiment of the present invention, the ultraviolet sterilization intensity can be controlled by changing the liquid milk flow rate; the selected liquid milk flow rate is 50-200 mL/min; specifically, fresh liquid milk is taken and the liquid milk temperature is maintained at 25 ℃, after passing through 5 sterilization areas, the flow rate of liquid milk in the tube is controlled to 50-200mL/min, and the corresponding UV dose is 65-16mJ/cm ² .

In one embodiment of the present invention, the sterilization intensity can be controlled by changing the length of the PFA tube 4; 2-6 sterilization areas are selected, and the number of winding turns in each area is 12 (the length of each circle of PFA 4 is 1m); Specifically, take fresh liquid milk, keep the temperature of the liquid milk at 25°C, and control the opening and closing of the three-way valve 3 to make the liquid milk pass through 2-6 sterilization areas, and the corresponding UV dose is 16-47mJ/cm ² .

In one embodiment of the present invention, the processing capacity of the highly active liquid emulsion can be adjusted by changing the number of 15 parallel-connected ultraviolet sterilization components; because the appropriate processing capacity of each ultraviolet lamp tube is 50-200mL/min, the UV The number of sterilization components 15 can be 1-100. Correspondingly, the number of heating tubes 17 and diverters 16 can be 1-10. When the number of ultraviolet sterilization components 15 is multiple, placed in parallel, the processing capacity of the ultraviolet sterilizer can be is 3-1200L/h.

In one embodiment of the present invention, the flow rate of liquid milk in the PFA tube 4 of the ultraviolet sterilizer is 50-200 mL/min.

In one embodiment of the present invention, the liquid milk passes through 2-6 sterilization areas, the number of winding turns of the PFA tube in each sterilization area is 12 turns, and the length of each turn of the PFA tube is 1 m.

In one embodiment of the present invention, the liquid milk can be heated to a certain temperature through a heating tube before receiving ultraviolet irradiation; during ultraviolet sterilization, the liquid milk can be maintained at a certain temperature through a temperature control system, which can be adjusted The temperature range is 0-80℃.

The third object of the present invention is the highly active liquid milk produced by the method of the present invention.

In one embodiment of the present invention, the highly active liquid milk is one of skim milk, whole cow milk, skim goat milk, and whole goat milk.

Beneficial effects of the present invention:

(1) The present invention provides an ultraviolet sterilizer for producing highly active liquid milk, which realizes ultraviolet sterilization of turbid liquids such as liquid milk. The present invention adopts the form of PFA tube 4 spirally surrounding and controls the D/Dc range to be 0.03-0.1, so that the liquid milk is fully mixed when running in the tube, thereby improving the sterilization efficiency of the liquid milk; the present invention changes the flow rate of the liquid milk Or the length of the liquid milk running in the PFA tube 4 changes the ultraviolet dose received by the milk, thereby controlling the sterilization intensity of the liquid milk; the present invention changes the processing capacity of the liquid milk by changing the number of parallel ultraviolet lamp tubes, which is easy to operate and consumes It takes less time, can meet a variety of processing requirements, and is widely used.

(2) The present invention provides a UV sterilization method for producing highly active liquid milk. There are various ways to change the UV dose, which is convenient and fast. The ultraviolet sterilization method in the present invention can make the number of microorganisms in liquid milk meet the requirements of national standards, and at the same time, the damage to active proteins in liquid milk is significantly lower than pasteurization (72°C 15s), which has the weakest heat treatment intensity, and will hardly cause obvious loss of active protein.

(3) The present invention provides a highly active liquid milk. Compared with pasteurization (72℃ 15s), the highly active liquid milk produced by this method has the same safety, but has more immunoactive proteins and antibacterial proteins. It is a highly active pasteurized liquid milk. .

(4) IgG, IgM, IgA and lactoferrin in milk are collectively called immunoactive proteins, which have antibacterial, defense, anti-inflammatory, antioxidant, anti-cancer and immunomodulatory functions. In addition, the two enzymes LPO and XO also have antibacterial activity and are beneficial enzymes in milk. The retention of these bioactive proteins plays an important role in promoting human intestinal health and immune function. By changing the liquid milk flow rate or the actual length of the PFA tube 4, the UV dose is changed to obtain highly active liquid milk. After ultraviolet sterilization of this liquid milk, the total number of bacterial colonies is 0-40000CFU/mL, and the number of coliform bacteria is 0CFU/mL, both within the range of national standards (GB19645-2010, GB 19301-2010). The content or activity of bioactive proteins and antibacterial enzymes in milk after sterilization, including IgG, IgM, IgA, lactoferrin, peroxidase, and xanthine oxidase, did not decrease significantly compared with before sterilization (while pasteurized milk Sterilization reduces it by 20-60%) and is a highly active liquid milk. The intensity of UV sterilization can be adjusted according to the hygienic quality of raw milk.

Description of the drawings

Figure 1 shows the structure of the ultraviolet sterilization component 15 inside the ultraviolet sterilizer;

Figure 2 is the main view (perspective) of the UV sterilizer;

Figure 3 is a left view (perspective) of the UV sterilizer;

Figure 4 is a top view (perspective) of the UV sterilizer;

In Figure 1-4, gasket 1, UV intensity monitor 2, three-way valve 3, PFA tube 4, UV lamp 5, quartz sleeve 6, PFA tube fixing clamp 7, feed pump 8, console 9. Lamp holder 10, UV lamp bracket 11, shell bracket 12, stainless steel shell 13, partition 14, UV sterilization component 15, diverter 16, heating tube 17.

Figure 5 shows the effects of two UV doses on the immunoactive protein content of milk in Example 6; A is the effect on IgG content; B is the effect on lactoferrin content; C is the effect on IgM content; D is the effect on Effect of IgA content.

Figure 6 shows the effects of two UV doses on the contents of milk peroxidase (LPO) and xanthine oxidase (XO) in Example 6.

Detailed ways

Preferred embodiments of the present invention are described below. It should be understood that the embodiments are for the purpose of better explaining the present invention and are not intended to limit the present invention.

Determination of the total number of bacterial colonies: Use the 3M company's total bacterial colony test piece (6406), take 1mL of the diluted sample, drop it in the center of the test piece, then press the upper film, let it sit for 1 minute until the culture medium solidifies, and then place it in a 32°C incubator Incubate for 24 hours, and count test pieces with 25-250 colonies.

Determination of coliforms: Use 3M company's total bacterial colony test piece (6416), take 1mL of the diluted sample, drop it in the center of the test piece, then press the upper film, let it stand for 1 minute until the culture medium solidifies, and then incubate at 32°C Incubate in the box for 12 hours, and count the test pieces with 15-150 colonies.

Determination of the total number of spores: Put a certain amount of processed milk into a sterile centrifuge tube and place it in an 80°C water bath for 10 minutes. After the incubation is completed, immediately cool it in crushed ice, take an appropriate amount of milk, dilute it to a certain multiple, and conduct subsequent measurements according to the total bacterial colony determination method.

Determination of immunoactive protein (IgG, IgM, IgA, lactoferrin) content: Elisa kit (Cat. No. E10-118, E10-131, E10-101 and E10-126; Bethyl Laboratories, USA) was used to determine the content of milk. IgG, IgM, IgA and lactoferrin content. The milk was diluted 500-1000 times for measurement, and a 4-parameter equation was used to fit and quantify the standard curve.

Lactoperoxidase (LPO) activity determination: The activity is determined by measuring the rate of the red fluorescent oxidation product (9-hydroxy-3-isophenoxazolone) generated by the oxidation reaction of Amplex Red dye (AR) catalyzed by lactoperoxidase. size. Mix 23.1μL AR, 4.6μL potassium thiocyanate solution and 972.3μL 100mM phosphate buffer (PH 7.4) to prepare the reaction reagent. Mix 30μL diluted milk with 195μL reaction reagent, then add 50μL of the mixed solution to the 96-well plate. After incubating at 37°C for 20 minutes, use a microplate reader to automatically add 50 μL of 110 μM hydrogen peroxide solution (replace the hydrogen peroxide solution with 50 μL of deionized water for the blank), and measure the fluorescence at the excitation/emission wavelength of 544/590 nm every 10 s. strength. Prepare a standard curve using hydrogen peroxide solutions with different concentration gradients. Lactoperoxidase activity is calculated by the following formula (3):

Note: F1 and F2 are the differences in fluorescence intensity between the two endpoints within T time, and K is the slope of the standard curve.

Determination of xanthine oxidase (XO) activity: Xanthine oxidase can catalyze hypoxanthine to produce hydrogen peroxide, and hydrogen peroxide can be catalyzed by horseradish peroxidase (HRP) to produce a fluorescent product. Mix 10 μL of 10mM AR, 4μL of 200U/mL HRP, 40μL of 10mM hypoxanthine, and 946μL of phosphate buffer (pH 7.4) to prepare reaction reagents. Add 50 μL of diluted milk to a 96-well plate, then add 50 μL of xanthine oxidase reaction reagent to mix, and measure the fluorescence intensity at excitation/emission wavelengths of 544/590 nm with a microplate reader every 30 s. Prepare a standard curve using hydrogen peroxide solutions with different concentration gradients. The xanthine oxidase activity is calculated by the following formula (4):

Note: F1 and F2 are the differences in fluorescence intensity between the two endpoints within T time, and K is the slope of the standard curve.

Embodiment 1 UV sterilizer (one UV sterilization component 15)

The ultraviolet sterilization machine includes an ultraviolet sterilization component 15, a feed pump 8, a console 9, a lamp holder 10, an ultraviolet lamp bracket 11, a shell bracket 12, and a stainless steel shell 13. The ultraviolet sterilization component 15 includes a gasket 1, an ultraviolet sterilizer Intensity monitor 2, three-way valve 3, PFA tube 4, UV lamp 5, quartz sleeve 6, PFA tube fixing clip 7; among them, the stainless steel shell 13 is supported by the shell bracket 12; the stainless steel shell 13 contains 1 UV lamp Tube 5, UV lamp tube 5 is fixed by lamp tube holder 10 and UV lamp bracket 11; the surface of UV lamp tube 5 is covered with quartz sleeve 6, and there is a layer of gasket 1, PFA, between UV lamp tube 5 and quartz sleeve 6 The tube 4 is tightly wound around the quartz casing 6. There is no gap between the PFA tube 4 and the quartz casing 6. The PFA tube 4 is wound around 10-30 times as a sterilization area. The entire sterilization area is fixed by the PFA tube fixing clip 7, adjacent to The PFA pipe 4 in the sterilization area is connected with a three-way valve 3; the UV intensity detector 2 is closely attached to the outside of the quartz sleeve 6 where the PFA pipe is not wrapped; one side of the UV sterilizer is equipped with a feed pump 8, and the other side Comes with console 9.

During operation, the liquid milk enters one end of the PFA pipe 4 through the feed pump 8. The liquid milk flows around the pipe for several weeks. After being irradiated by ultraviolet light, it flows out from the other end of the PFA pipe 4. By controlling the opening of the three-way valve 3 Close, the flow direction of the liquid milk in the PFA tube 4 can be changed, so that the liquid milk can enter the next area to continue UV sterilization, or end the sterilization and flow out directly. The ultraviolet intensity detector 2 is closely attached to the outside of the quartz casing and can accurately monitor the ultraviolet intensity measured outside the quartz casing. The stainless steel shell 13 is strictly sealed and equipped with a temperature control system inside, which can control the temperature of the ultraviolet sterilization module (0-80°C) through a water bath. The console 9 can control the UV lamp, UV intensity monitor and the temperature within the stainless steel housing 13 . By controlling the feed pump 8, the number of ultraviolet lamps connected in parallel can be selected, thereby changing the processing capacity of ultraviolet sterilization.

Embodiment 2 Ultraviolet sterilizer (multiple parallel ultraviolet sterilization components 15)

The front view, top view, side view and schematic diagram of the internal UV sterilization module of the UV sterilizer are shown in Figures 1, 2, 3 and 4 respectively. The UV sterilizer has UV sterilization components 15, feed pump 8, console 9, lamp holder 10, UV lamp bracket 11, shell bracket 12, stainless steel shell 13, partition 14, diverter 16, heating tube 17 , the ultraviolet sterilization component 15 includes a gasket 1, an ultraviolet intensity monitor 2, a three-way valve 3, a PFA tube 4, an ultraviolet lamp tube 5, a quartz sleeve 6, and a PFA tube fixing clip 7; among them, the stainless steel shell 13 is composed of a shell bracket 12 Support; the stainless steel shell 13 contains a plurality of ultraviolet lamp tubes 5. The plurality of ultraviolet lamp tubes 5 are separated by partitions 14. The ultraviolet lamp tubes 5 are fixed by a lamp tube holder 10 and an ultraviolet lamp bracket 11; the ultraviolet lamp tubes 5. The surface is covered with a quartz sleeve 6. There is a layer of gasket 1 between the UV lamp 5 and the quartz sleeve 6. The PFA tube 4 is tightly wound around the quartz sleeve 6. There is no gap between the PFA tube 4 and the quartz sleeve 6. , the PFA tube 4 is wound around 10-30 times as a sterilization area. The entire sterilization area is fixed by the PFA tube fixing clip 7. The PFA tubes 4 in adjacent sterilization areas are connected with a three-way valve 3; the UV intensity detector 2 is closely attached to the quartz sleeve The outside of tube 6 is where the PFA tube is not wrapped; one side of the UV sterilizer is equipped with a feed pump 8 and the other side is equipped with a console 9; there is heating around the PFA tube 4 between the feed pump 8 and the stainless steel shell 13 Pipe 17; diverter 16 between feed pump 8 and stainless steel housing 13.

During operation, the liquid milk passes through the feed pump 8, passes through the heating tube 17 and the diverter 16, and enters one end of the PFA tube 4. The liquid milk flows around the tube for several weeks, and then flows from the other end of the PFA tube 4 after being irradiated by ultraviolet light. One end flows out, and by controlling the opening and closing of the three-way valve 3, the flow direction of the liquid milk in the PFA tube 4 can be changed, so that the liquid milk can enter the next area to continue UV sterilization, or end the sterilization and flow out directly. The ultraviolet intensity detector 2 is closely attached to the outside of the quartz casing and can accurately monitor the ultraviolet intensity measured outside the quartz casing. The stainless steel shell 13 is strictly sealed and equipped with a temperature control system inside, which can control the temperature of the ultraviolet sterilization module (0-80°C) through a water bath. The console 9 can control the temperature in the ultraviolet lamp 5, the ultraviolet intensity monitor 2, the feed pump 8, the heating tube 17 and the stainless steel shell 13. The shunt 16 can connect up to ten PFA tubes 4 in parallel at the same time. By controlling the shunt 16, the number of ultraviolet lamp tubes connected in parallel can be selected, thereby changing the processing capacity of the ultraviolet sterilization.

Example 3 The sterilizer of Example 1 is used for milk sterilization

In order to ensure that the milk is fully mixed when moving in the PFA tube 4, the Reynolds number (Re) and Dean number (De) are calculated according to equations (1) and (2):

where ρ is the density of milk, which is 1021.46kg/m ² ; μ is the dynamic viscosity of milk, which is 1.941×103Ns/m ² ; v is the flow rate of milk in the tube; D is the inner diameter of PFA tube 4; Dc is the surrounding area of PFA tube 4 the inside diameter of.

Re<2100 indicates that the liquid flow state is laminar flow, Re>4000 indicates that the liquid flow state is turbulent flow, and Re is between the two, indicating a mixed flow state. De is a representation of the way fluid flows in the coil. When 0.03<D/Dc<0.1, the fluid in the coil produces secondary flow pockets, which can enhance the degree of fluid mixing.

Set up the UV sterilizer according to the combination of PFA tubes with different specifications and quartz sleeves with different outer diameters in Table 1, so that the milk will be sterilized through two areas. Calculate Re and D/Dc, and calculate the milk through the following formulas (5) and (6) UV dose received:

UV-C dose (mJ/cm ² ) = UV-C intensity (mW/cm ² ) × treatment time (s) × PFA tube 4UV-C transmittance (%) (6)

It can be seen from Table 1: Since the outer diameter of a section of the UV lamp is 19mm, the possible inner diameter of the quartz sleeve is at least 20mm. It can be seen that the main factor that determines the ratio is the PFA tube specification. Therefore, when the outer diameter of the quartz casing is 20-30mm, PFA tubes of 1*2mm, 1.5*2.5mm, 1.5*3mm, 2*3mm, and 2*4mm should be used; when the outer diameter of the quartz casing is 20-30mm When using, PFA tubes of 1*2mm, 1.5*2.5mm, 1.5*3mm, 2*3mm, and 2*4mm should be used.

Table 1 D/Dc values under the combination of PFA pipes of different specifications and quartz casings of different outer diameters

The performance test of the sterilized milk was performed, and the test results are shown in Table 2. As can be seen from Table 2, although the D/Dc value of the 2*4mm PFA tube meets the requirements, the total number of bacteria does not meet the pasteurization standard. It may be that the tube wall is too thick, resulting in low UV transmittance, which affects the sterilization effect. Therefore, the available PFA tube specifications are 1mm*2mm, 1.5mm*2.5mm, and 2mm*3mm.

Table 2 Bactericidal effects under different specifications of PFA tubes

Note: "-" means there is less than 1 colony on the plate and it is considered undetectable.

Comparative Example 1 Sterilization effects of different ultraviolet sterilization equipment

Milk is sterilized using DC-type and static UV sterilization equipment on the market. DC-type equipment (Ster New York, NY, USA) mainly consists of a UV lamp, a quartz sleeve wrapped around the outside of the lamp, and a metal sleeve 1.5mm away from the quartz sleeve. During sterilization, milk flows along the axis between the quartz sleeve and the metal sleeve. Stationary equipment (customized with reference to literature: MalekAmiali et al, Inactivation of Staphylococcus aureus (ATCC 6538), Escherichia coli (ATCC 25922) and Pseudomonasaeruginosa (ATCC 9027) in Skimmed Bovine Milk using UltraViolet-C Irradiation, International Journal of Advanced Research (2015 ), Volume 3, Issue 5, 387-395) consists of a metal box with an ultraviolet lamp installed on the top of the box. The sample is placed at the bottom of the box and evenly spread in the circular sample pool. The sample height is 1.5mm.

Control the flow rate of milk in the DC-type equipment and the irradiation time of the ultraviolet lamp in the static equipment. Control the surface ultraviolet dose of the three types of ultraviolet sterilization methods in contact with the milk and ultraviolet light to 31mJ/cm ² , and measure the total number of bacteria.

The test results of the sterilized milk obtained in Example 3 and Comparative Example 1 are shown in Table 3. It can be seen from Table 3 that under the same ultraviolet dose, the total number of milk bacteria after sterilization with spiral tube equipment (Example 1) is the smallest and the sterilization intensity is the highest. Therefore, the spiral tube type ultraviolet sterilizer of the present invention has high sterilization intensity and high efficiency.

Table 3 Test results of sterilized milk obtained in Example 3 and Comparative Example 1

Example 4 Changing the milk flow rate (Q) to change the UV dose

Choose a PFA tube with an inner diameter of 1.5mm and an outer diameter of 2.5mm.

Take fresh milk, keep the milk temperature at 25°C, and pass through 5 sterilization areas. Control the flow rate of milk in the tube to 50, 100, and 200mL/min respectively, and the corresponding UV doses are 65mJ/cm ² , 33mJ/cm ² , and 16mJ/ cm ² ; after UV sterilization, the milk is placed in a sterile bottle and immediately placed in crushed ice.

At the same time, the same batch of fresh milk (the total number of colonies is 5.48±0.03log(CFU/mL), the number of coliforms is 2.77±0.01log(CFU/mL)) was pasteurized (72°C for 15s) as a control. The total number of pasteurized milk colonies (72°C for 15 seconds) is 2.45±0.05log (CFU/mL) and does not contain coliform bacteria.

The total number of bacterial colonies and coliforms in the milk before and after sterilization were measured. The test results are shown in Table 4:

China's microbial limit standard for raw milk is 2×10 ⁶ (CFU/mL); the total bacterial colony limit for pasteurized milk is 50,000 (CFU/mL), and the coliform limit is 5 (CFU/mL). The data in Table 4 shows that raw milk, pasteurized milk and three doses of UV sterilized milk all meet the requirements of national standards (GB 19645-2010, GB 19301-2010). Among them, when the milk flow rate is 100mL/min (UV dose is 33mJ/cm ² ), the sterilization effect is the best. As the flow rate increases, the time the milk receives ultraviolet irradiation in the tube becomes shorter, resulting in a weakened sterilization effect; the flow rate decreases, and the milk flows faster in the tube. It slows down and the UV exposure time becomes longer. However, because the flow rate is too slow and the Reynolds number is too small, the degree of mixing of milk in the tube is not as vigorous as when the flow rate is high, so the sterilization effect is weak.

Table 4 Test results of Example 4

Note: "-" means there is less than 1 colony on the plate and it is considered undetectable.

Example 5 Changing the UV dose by changing the length of PFA tube 4

Select a PFA tube 4 with an inner diameter of 1.5mm and an outer diameter of 2.5mm to control the flow of milk in the tube to 150mL/min. By opening and closing the three-way valve 3, the milk passes through 2, 3, 4, 5, and 6 respectively. In the sterilization area (the length of each sterilization area is 1m, and it is wound 12 times), the UV doses of the five treatment methods are 16, 23, 31, 39, and 47mJ/cm ² respectively. After UV sterilization, the milk is placed in a sterile bottle and immediately placed in crushed ice.

At the same time, the same batch of fresh milk (the total number of colonies is 5.02±0.02log(CFU/mL), the number of coliforms is 2.02±0.02log(CFU/mL)) was pasteurized (72°C for 15s) as a control. The total number of pasteurized milk colonies (72°C for 15 seconds) is 1.18±0.00log (CFU/mL) and does not contain coliform bacteria.

Determine the total number of colonies and coliforms in the milk before and after sterilization. The test results are shown in Table 5:

From the data in Table 5 combined with the national standards (GB 19645-2010, GB 19301-2010), it can be seen that the total number of colonies and coliform bacteria in ultraviolet sterilized milk for the five parameters all meet the requirements of the national standards. When the PFA tube 4 is wound for more than 3m, the UV sterilization effect of milk is equivalent to pasteurization (72°C for 15s).

Table 5 Test results of Example 5

Note: "-" means there is less than 1 colony on the plate and it is considered undetectable.

Example 6 Effect of UV Sterilization on Milk Active Protein

The milk flow rate is 100mL/min, passing through 4 sterilization areas (UV dose is 26mJ/cm ² , recorded as UV4-100), and the milk flow rate is 150mL/min, passing through 6 sterilization areas (UV dose is 47mJ/cm ² , recorded as UV6-150), taking two sterilization parameters as an example, determine the contents of milk immunoglobulins (IgG, IgA, IgM) and lactoferrin, lactoperoxidase LPO and xanthine oxidase XO before and after UV sterilization Activity, original milk (marked as R) and pasteurized milk (72°C 15s) (marked as H) were used as controls.

The test results are shown in Table 6, Table 7 and Figure 5 and Figure 6: It can be seen from Table 6 that the milk sterilized with two UV doses meets the national standard requirements for pasteurized milk. After ultraviolet sterilization, it can be seen from the number of spores that pasteurization can only kill the bacterial vegetative bodies in the milk, but not the spores. Ultraviolet sterilization can not only kill the bacterial vegetative bodies, but also kill some spores. It can be seen from Table 7, Figure 5 and Figure 6 that pasteurization leads to a significant reduction of four immunoactive proteins, LPO and XO in milk, while two types of ultraviolet sterilization have no significant impact on these six biologically active substances. Therefore, using this The invented ultraviolet sterilization method can produce highly active milk.

Table 6 Bactericidal test results of Example 6

Note: "-" means there is less than 1 colony on the plate and it is considered undetectable.

Table 7 Activity test results of Example 6

Although the present invention has been disclosed above in terms of preferred embodiments, they are not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the technology and scope of the present invention. Therefore, The protection scope of the present invention should be defined by the claims.

Claims (4)

1. A method for producing highly active liquid emulsion using an ultraviolet sterilizer, characterized in that the ultraviolet sterilizer includes an ultraviolet sterilization component 15, a feed pump 8, a console 9, a lamp holder 10, and an ultraviolet lamp bracket 11. Shell bracket 12, stainless steel shell 13, UV sterilization component 15 includes gasket 1, UV intensity monitor 2, three-way valve 3, PFA tube 4, UV lamp 5, quartz sleeve 6, PFA tube fixing clip 7; Among them, the stainless steel shell 13 is supported by the shell bracket 12; the stainless steel shell 13 contains a UV lamp 5, and the UV lamp 5 is fixed by the lamp holder 10 and the UV lamp bracket 11; the surface of the UV lamp 5 is covered with a quartz sleeve 6. There is a layer of gasket 1 between the UV lamp tube 5 and the quartz sleeve 6. The PFA tube 4 is tightly wound around the quartz sleeve 6. There is no gap between the PFA tube 4 and the quartz sleeve 6. The PFA tube 4 is wound 10- 30 circles are used as a sterilization area, and the length of each sterilization area is 1m. The entire sterilization area is fixed by a PFA tube fixing clip 7. The PFA tubes 4 in adjacent sterilization areas are connected with a three-way valve 3; the ultraviolet intensity detector 2 is closely attached to The outside of the quartz sleeve 6 is where the PFA tube is not wrapped; one side of the UV sterilizer is equipped with a feed pump 8 and the other side is equipped with a console 9; During operation, the liquid milk enters one end of the PFA pipe 4 through the feed pump 8. The liquid milk flows around the pipe for several weeks. After being irradiated by ultraviolet light, it flows out from the other end of the PFA pipe 4. By controlling the opening of the three-way valve 3 Close, the flow direction of the liquid milk in the PFA tube 4 can be changed, so that the liquid milk can enter the next area to continue UV sterilization, or end the sterilization and flow out directly; the UV intensity detector 2 is close to the outside of the quartz sleeve and can accurately monitor The ultraviolet intensity is measured externally by the quartz sleeve; the stainless steel shell 13 is strictly sealed and equipped with a temperature control system inside, which can control the temperature of the ultraviolet sterilization module from 0 to 80°C through a water bath; the console 9 can control the ultraviolet lamp, ultraviolet intensity monitor and stainless steel The temperature inside the housing 13; Among them, the usage specifications of the PFA pipe 4 are that the inner diameter is 1-2mm and the outer diameter is 2-3mm; the ratio of the surrounding inner diameter Dc of the PFA pipe 4 to the inner diameter D of the PFA pipe 4 is between 0.03-0.1; The flow rate of liquid milk in the PFA tube 4 of the UV sterilizer is 100-150 mL/min; The liquid milk passes through 4-6 sterilization areas, and the corresponding UV dose is 26-47 mJ/cm ² . 2. A method for producing highly active liquid emulsion using an ultraviolet sterilizer, characterized in that the ultraviolet sterilizer has an ultraviolet sterilization component 15, a feed pump 8, a console 9, a lamp holder 10, and an ultraviolet lamp bracket 11 , Shell bracket 12, stainless steel shell 13, partition 14, diverter 16, heating tube 17, UV sterilization component 15 includes gasket 1, UV intensity monitor 2, three-way valve 3, PFA tube 4, UV lamp 5, Quartz sleeve 6, PFA tube fixing clip 7; among them, the stainless steel shell 13 is supported by the shell bracket 12; the stainless steel shell 13 contains multiple UV lamp tubes 5, and the multiple UV lamp tubes 5 are separated by partitions 14. The UV lamp 5 is fixed by the lamp holder 10 and the UV lamp bracket 11; the surface of the UV lamp 5 is covered with a quartz sleeve 6, there is a layer of gasket 1 between the UV lamp 5 and the quartz sleeve 6, and the PFA tube 4 is tightly Wound around the quartz casing 6, there is no gap between the PFA tube 4 and the quartz casing 6. The PFA tube 4 is wound 10-30 times as a sterilization area. The length of each sterilization area is 1m. The entire sterilization area is fixed by the PFA tube. Clamp 7 is fixed, and the PFA tube 4 in the adjacent sterilization area is connected with a three-way valve 3; the UV intensity detector 2 is close to the outside of the quartz sleeve 6 where the PFA tube is not wrapped; one side of the UV sterilizer is equipped with a feed Pump 8, the other side is equipped with a console 9; there is a heating pipe 17 around the PFA pipe 4 between the feed pump 8 and the stainless steel shell 13; the diverter 16 is between the feed pump 8 and the stainless steel shell 13; During operation, the liquid milk passes through the feed pump 8, passes through the heating tube 17 and the diverter 16, and enters one end of the PFA tube 4. The liquid milk flows around the tube for several weeks, and then flows from the other end of the PFA tube 4 after being irradiated by ultraviolet light. One end flows out, and by controlling the opening and closing of the three-way valve 3, the flow direction of the liquid milk in the PFA tube 4 can be changed, so that the liquid milk enters the next area to continue UV sterilization, or ends the sterilization and flows out directly; UV intensity detector 2 Closely attached to the outside of the quartz casing, it can accurately monitor the UV intensity measured outside the quartz casing; the stainless steel shell 13 is strictly sealed, and is equipped with a temperature control system inside, which can control the temperature of the UV sterilization module 0-80°C through a water bath; the console 9 It can control the temperature inside the UV lamp 5, UV intensity monitor 2, feed pump 8, heating tube 17 and stainless steel shell 13; the shunt 16 can connect up to ten PFA tubes 4 in parallel at the same time. By controlling the shunt 16, you can select The number of ultraviolet lamps connected in parallel changes the processing capacity of ultraviolet sterilization; Among them, the usage specifications of the PFA pipe 4 are that the inner diameter is 1-2mm and the outer diameter is 2-3mm; the ratio of the surrounding inner diameter Dc of the PFA pipe 4 to the inner diameter D of the PFA pipe 4 is between 0.03-0.1; The flow rate of liquid milk in the PFA tube 4 of the UV sterilizer is 100-150 mL/min; The liquid milk passes through 4-6 sterilization areas, and the corresponding UV dose is 26-47 mJ/cm ² . 3. The method according to claim 2, characterized in that the number of ultraviolet sterilization components 15 in the ultraviolet sterilization device can be 1-100, and correspondingly, the number of heating tubes 17 and diverters 16 can be 1-10. ; When the number of UV sterilization components is multiple, placed in parallel, the processing capacity of the UV sterilizer can be 3-1200L/h. 4. Highly active liquid milk produced by the method of any one of claims 1-3.