Multi-channel fluorescence detection system and detection method for food-borne pathogenic bacteria

Abstract

The invention discloses a multi-channel fluorescence detection system and a detection method for food-borne pathogenic bacteria, and relates to the technical field of fluorescence detection and analysis. The problem that multiple samples or multiple fluorescent dyes cannot be detected at the same time in the prior art is solved. The multi-channel fluorescence detection system comprises a shell, a flip cover, a base and a fixed shaft, the shell and the flip cover are fixed with the base through the fixed shaft, a fluorescence imaging unit is arranged on the flip cover and is used for processing image information of a sample solution in the sample platform, and an optical detection unit for performing fluorescence detection on a to-be-detected sample is arranged on the base and is used for processing the image information of the sample solution in the sample platform. The sample platform is controlled by the switching motor to rotate so as to detect different channels, and the optical detection unit comprises an excitation light path and an emission light path, wherein the excitation light path is used for generating excitation light and enabling the excitation light to enter the sample platform, and the emission light path is used for detecting reflected detection light. The system is mainly suitable for detecting food-borne pathogenic bacteria and is also suitable for the fields of substances such as viruses, bacteria and hormones.

Description

Technical Field

[0001] The present invention relates to the technical field of fluorescence detection and analysis, and in particular to a multi-channel fluorescence detection system and a detection method for foodborne pathogens. Background Art

[0002] Foodborne pathogens refer to fungi or bacteria that can be transmitted through food and, after entering the human body, can cause damage to the human body or even cause death. Common foodborne pathogens include Salmonella, Bacillus cereus, Vibrio parahaemolyticus, Escherichia coli, botulinum toxin, Staphylococcus enterotoxin, Proteus, Aeromonas, Shigella, Klebsiella pneumoniae, Pseudomonas cocovenenans, etc. The detection technology of foodborne pathogens is also a key link in the prevention and control of foodborne diseases.

[0003] The main detection methods in the existing foodborne pathogen detection implementation standards are culture method, ELLISA method and PCR method. Among them, the culture method is the most widely used method, and the results are accurate, but it is time-consuming, complicated to operate, and requires professional training for personnel. The ELLISA method has many operating steps, poor sensitivity, and is prone to false negatives. The PCR method requires the purchase of equipment, the deployment of professional technicians, and the process is complicated and cumbersome, and the detection cycle is long.

[0004] Although there are many testing methods and supporting instruments for foodborne pathogens, the existing instruments are generally based on PCR technology for fluorescence detection, and most of them are single-channel confocal systems. They can only detect one fluorescent reagent at a time, with low detection efficiency, and cannot meet the purpose of detecting multiple fluorescent reagents at the same time; or the single-channel systems are mechanically superimposed or integrated, and each independent detection system and each separate reagent to be detected are connected with optical fiber. Even if the detection efficiency is improved compared to the single-channel system, the entire system is large in size and high in cost. For example, a Chinese patent application with publication number CN112695111A discloses a PCR detection system and construction method for simultaneously detecting multiple foodborne pathogens; the primers and annealing temperature of the initial detection system are optimized by single-plex PCR of five bacteria, and the annealing temperature is further optimized to 50-59.2°C by triple-plex PCR, and the annealing temperature is optimized to 58°C and 53.8°C by quadruple-PCR. Within this range, the annealing temperature is optimized to 54°C by quintuple-PCR, and the concentration value of the primer used for each bacteria is further optimized, and finally a PCR detection system that can simultaneously detect multiple foodborne pathogens is obtained. The detection system can perform parallel detection of multiple target genes, with low detection cost and greatly improved detection efficiency; but it is necessary to prepare primers and accurately control the temperature, and the operation is cumbersome and time-consuming.

[0005] Or, as disclosed in a Chinese patent application with publication number CN117330480A, a multi-channel fluorescence detection system includes a mounting structure, a pinhole filter assembly, multiple groups of branch assemblies, an objective lens, and a camera; the mounting structure includes a first connection portion, a second connection portion, and a reflector; the pinhole filter assembly is disposed between the first connection portion and the second connection portion, and a first optical path is formed between the first connection portion and the second connection portion; multiple groups of branch assemblies are connected to the second connection portion and are located downstream of the reflector to form a second optical path parallel to the first optical path. By arranging the mounting structure to cooperate with the pinhole filter assembly, the pinhole filter assembly can be placed in front of the branch assembly, and the overall structure of the multi-channel fluorescence detection system is compact and the scalability is also improved. However, the filter assembly is shared, and switching is cumbersome and prone to interference.

[0006] Many foods, such as milk and dairy products, meat and poultry, and fruits and vegetables, are often carriers of multiple pathogens; the existing technology mostly uses a single-channel optical system to detect the target sample, which can only detect one pathogen in the sample at a time, and the detection efficiency is low. At present, most reports on the detection of foodborne pathogens are in the field of biochemistry, and there are few reports on complete detection systems.

[0007] In addition, both the photoelectric detection method and the fluorescence imaging detection method require an optical darkroom. If one light source is used to excite all fluorescence channels, the spectral utilization rate of the light source will be low, that is, most of the light energy will serve as background interference, affecting signal acquisition. Some devices require the drive of a motion mechanism to achieve switching between different fluorescence channels. There is a relatively obvious fluorescence crosstalk phenomenon between different fluorescence channels, which affects the fluorescence detection effect, and there is room for improvement.

[0008] Secondly, many fluorescent dyes nowadays have rapid quenching properties. When performing step-by-step detection of multiple fluorescent channels, the quenching effect of fluorescence is difficult to measure because the sample is repeatedly irradiated or the irradiation time is different. With the advancement of the times, the requirements for the advancement, sensitivity and specificity of detection technology are higher. Summary of the invention

[0009] The present invention aims to solve the problem in the prior art that there is a lack of the ability to simultaneously detect multiple samples or multiple fluorescent dyes.

[0010] To solve the above technical problems, the present invention is achieved through the following technical solutions:

[0011] Solution 1: The present invention proposes a multi-channel fluorescence detection system for foodborne pathogens, the multi-channel fluorescence detection system comprising a housing, a flip cover, a base, and a fixed shaft, the housing and the flip cover are fixed to the base via the fixed shaft, a fluorescence imaging unit is provided on the flip cover for processing image information of a sample solution in a sample platform, an optical detection unit for performing fluorescence detection on a sample platform to be tested is provided on the base, and the sample platform is controlled to rotate by switching a motor so that different channels can be detected,

[0012] The optical detection unit includes an excitation light path for generating excitation light and allowing the excitation light to enter the sample platform and formed, and an emission light path for detecting detection light emitted after reflection.

[0013] Furthermore, a preferred embodiment is provided, wherein the fluorescence imaging unit comprises a CMOS camera, a filter slot, an annular LED light source, and a fluorescence imaging unit circuit board, and the CMOS camera, the filter slot and the annular LED light source are on the same center line.

[0014] Furthermore, a preferred embodiment is provided, wherein the optical detection unit is in a four-leaf clover shape, and comprises a first optical detection unit, a second optical detection unit, a third optical detection unit, and a fourth optical detection unit, and the four optical detection units are exactly the same.

[0015] Further, a preferred embodiment is provided, wherein the excitation light path comprises:

[0016] An excitation light unit, used for generating excitation original light;

[0017] A collimating lens, used for converting the original excitation light generated by the optical exciter into parallel excitation light;

[0018] A first filter, used for filtering the excitation parallel light converted by the collimating lens to obtain monochromatic excitation light;

[0019] A dichroic mirror is used to reflect the excitation light onto the cuvette on the sample platform.

[0020] Further, a preferred embodiment is provided, wherein the detection optical path comprises:

[0021] A second filter is used to filter the detection parallel light emitted by the sample excited by the excitation light path to obtain monochromatic detection parallel light;

[0022] A second focusing lens is used to focus the monochromatic detection parallel light obtained after being filtered by the second filter;

[0023] The photoelectric detector is used to detect the monochromatic detection light focused by the second focusing lens.

[0024] Furthermore, a preferred embodiment is provided, wherein the axis of the collimating lens and the axis of the first focusing lens are perpendicular to each other, and the angles between the dichroic mirror and the axis of the collimating lens and the axis of the second focusing lens are all 45°.

[0025] Furthermore, a preferred embodiment is provided, wherein the switching motor is a stepping motor.

[0026] Furthermore, a preferred embodiment is provided, wherein the stepper motor is further provided with a first pulley, a belt and a second pulley, wherein the first pulley is provided on the stepper motor, one end of the belt is sleeved on the first pulley, and the other end of the belt is sleeved on the second pulley.

[0027] Furthermore, a preferred embodiment is provided, wherein a first optical detection unit support frame and a second optical detection unit support frame are also provided on the base for supporting the optical detection unit.

[0028] Scheme 2: A multi-channel fluorescence detection method using the multi-channel fluorescence detection system for foodborne pathogens as described in any one of Scheme 1, comprising the following steps:

[0029] S1. After the power is supplied, the touch screen will light up and you can select the operation to be performed.

[0030] S2, placing the sample platform into the detection system, touching the display screen to start detection, the stepper motor drives the sample platform to rotate the test tube to the specified position; the photoelectric detection unit emits excitation light to illuminate the sample platform, excites the fluorescence in the sample platform, and the fluorescence is transmitted to the main control module for processing through the signal acquisition and processing module; the photoelectric detection unit repeats the above operation;

[0031] S3, based on S2, the fluorescence imaging unit performs image acquisition and data processing, and after completion, the stepper motor rotates to make the second test tube slot reach a preset position, and continues the above operations;

[0032] S4. After the sample platform rotates eight times, eight rounds of photoelectric acquisition and image acquisition are completed, and finally the concentration information and image information of the sample foodborne pathogens are displayed on the touch screen.

[0033] The present invention is beneficial in that:

[0034] The multi-channel fluorescence detection system for foodborne pathogens described in the present invention can detect multiple samples or multiple fluorescent dyes at the same time, providing a reference for the rapid detection of multiple strains at the same time. The system combines the photoelectric detection method with the fluorescence imaging method, and can display image information on the display screen in real time. By superimposing and integrating the detection signals between the two, it can compensate for the loss of the photodiode in the photoelectric detection and improve the detection accuracy of the system. The detection system designed by the present invention is low-cost, has higher detection efficiency, is more portable, and can avoid wavelength interference between channels.

[0035] The present invention is suitable for detecting foodborne pathogens, and can also be used in the fields of viruses, bacteria, hormones and other substances. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 An overall block diagram of a multi-channel fluorescence detection system for foodborne pathogens described in Implementation Example 1.

[0037] Figure 2 This is a schematic diagram of the outer shell of a multi-channel fluorescence detection system for foodborne pathogens described in Implementation Example 1.

[0038] Figure 3 This is a schematic diagram of a flip cover in a multi-channel fluorescence detection system for foodborne pathogens described in Implementation Example 1.

[0039] Figure 4 This is a schematic diagram of a fluorescence imaging unit in a multi-channel fluorescence detection system for foodborne pathogens according to the first embodiment.

[0040] Figure 5 This is a side view of a fluorescence imaging unit in a multi-channel fluorescence detection system for foodborne pathogens described in Embodiment 1.

[0041] Figure 6 This is a schematic diagram of the assembly of the flip cover and the fluorescence imaging unit in the multi-channel fluorescence detection system for foodborne pathogens described in the first embodiment.

[0042] Figure 7 This is a schematic diagram of a base in a multi-channel fluorescence detection system for foodborne pathogens described in Implementation Example 1.

[0043] Figure 8 This is a side view of a base in a multi-channel fluorescence detection system for foodborne pathogens described in Embodiment 1.

[0044] Fig. 9 This is a schematic diagram of the installation of an optical detection unit and a belt combination in a multi-channel fluorescence detection system for foodborne pathogens described in embodiment eight.

[0045] Fig.10 This is a schematic diagram of circuit board positioning holes in a multi-channel fluorescence detection system for foodborne pathogens described in embodiment 11.

[0046] Fig.11 This is a schematic diagram of inserting the second pulley into the support column of the optical detection unit in the multi-channel fluorescence detection system for foodborne pathogens described in the eleventh embodiment.

[0047] Fig.12 This is a schematic diagram of a stepper motor driving a sample platform to rotate in a multi-channel fluorescence detection system for foodborne pathogens as described in Embodiment 11.

[0048] Fig.13 This is a schematic structural diagram of an optical detection unit embedded in a first optical detection unit support frame in a multi-channel fluorescence detection system for foodborne pathogens described in embodiment 11.

[0049] Fig.14 This is a schematic structural diagram of a first optical detection unit in a multi-channel fluorescence detection system for foodborne pathogens described in Embodiment 3.

[0050] Fig.15 This is a schematic diagram of the light path structure in an optical detection unit in a multi-channel fluorescence detection system for foodborne pathogens described in Implementation Example 1.

[0051] Fig.16 This is a schematic diagram of the device structure used for the excitation light path and the emission light path in a multi-channel fluorescence detection system for foodborne pathogens described in Implementation Example 1.

[0052] Fig.17 This is an exploded view of an optical detection unit in a multi-channel fluorescence detection system for foodborne pathogens described in Implementation Example 1.

[0053] Fig.18 This is a structural schematic diagram of a multi-channel fluorescence detection system for foodborne pathogens described in Implementation Example 1, in which eight sample tubes are inserted into a sample platform for detection.

[0054] Fig.19 This is a schematic diagram of detection of a fluorescence imaging unit in a multi-channel fluorescence detection system for foodborne pathogens described in Implementation Example 1.

[0055] Fig. 20 This is a schematic diagram of the detection light path of a fluorescence imaging unit in a multi-channel fluorescence detection system for foodborne pathogens described in Implementation Example 1.

[0056] Fig.21 This is a schematic diagram of the splicing of modules in a multi-channel fluorescence detection system for foodborne pathogens described in Implementation Example 1.

[0057] Fig. 22 This is a structural block diagram of a circuit board in a multi-channel fluorescence detection system for foodborne pathogens described in Implementation Example 11.

[0058] In the figure, a housing 1, a flip cover 2, a base 3, a fixed shaft 4, a touch display screen 5, a first flip cover positioning hole 6, a second flip cover positioning hole 7, a fixed shaft jack 8, a lead hole 9, an injection detection hole 10, a first flip cover positioning buckle 11, a second flip cover positioning buckle 12, a fluorescence imaging unit positioning slot 13, a fluorescence imaging unit 14, a CMOS sensor 15, a filter slot 16, an annular LED light source 17, a fluorescence imaging unit circuit board 18, an annular LED light source support column 19, a filter placement position 20, a fluorescence imaging unit LED 21, a circuit board placement position 22, a circuit board support column 23, a stepper motor placement slot 24, a first optical detection unit support frame 25, a second optical detection unit support frame 26, an optical detection unit support column 27, a first optical detection unit lead hole 28, a second optical detection unit lead hole 29, a first shoe Belt conveying channel 30, second crawler conveying channel 31, stepper motor 32, first pulley 33, optical detection unit 34, belt mounted assembly 35, circuit board positioning hole 36, second pulley 37, first optical detection unit 38, excitation light path 39, emission light path 40, excitation light unit 41, collimating lens 42, dichroic mirror 43, first focusing lens 44, second filter 45, second focusing lens 46, photodetector 47, second optical detection unit 48, third optical detection unit 49, fourth optical detection unit, sample platform 51, sample platform cover 52, first test tube slot 53, second test tube slot 54, fluorescence imaging detection hole 55, eighth test tube slot 56, cover pull rod 57, sample test tube 58, fluorescence imaging unit filter 59, fluorescence imaging unit excitation light path 60, fluorescence imaging unit emission light path 61. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solutions and advantages of the implementation methods of the present application clearer, the technical solutions in the implementation methods of the present application will be clearly and completely described below in conjunction with the drawings in the implementation methods of the present application. Obviously, the described implementation methods are only part of the implementation methods of the present application, not all of the implementation methods.

[0060] Embodiment 1. This embodiment provides a multi-channel fluorescence detection system for foodborne pathogens, the multi-channel fluorescence detection system includes a housing 1, a flip cover 2, a base 3, and a fixed shaft 4. The housing 1 and the flip cover 2 are fixed to the base 3 by the fixed shaft 4. The flip cover 2 is provided with a fluorescence imaging unit 14 for processing the image information of the sample solution in the sample platform 51. The base 3 is provided with an optical detection unit 34 for performing fluorescence detection on the sample platform 51 to be tested. The sample platform 52 is controlled to rotate by a switching motor 32 so that it can perform different channel detections.

[0061] The optical detection unit 34 includes an excitation light path 39 for generating excitation light and allowing the excitation light to enter the sample platform 51 and an emission light path 40 for detecting the detection light emitted after reflection.

[0062] Embodiment 2. This embodiment further limits the multi-channel fluorescence detection system for foodborne pathogens described in embodiment 1. The fluorescence imaging unit 14 includes a CMOS camera 15, a filter slot 16, an annular LED light source 17, and a fluorescence imaging unit circuit board 18. The CMOS camera 15, the filter slot 16 and the annular LED light source 17 are on the same center line.

[0063] Embodiment 3. This embodiment is a further limitation of the multi-channel fluorescence detection system for foodborne pathogens described in embodiment 1. The optical detection unit 34 is in a four-leaf clover shape. The optical detection unit 34 includes a first optical detection unit, a second optical detection unit, a third optical detection unit, and a fourth optical detection unit, and the four optical detection units are exactly the same.

[0064] Embodiment 4: This embodiment further limits the multi-channel fluorescence detection system for foodborne pathogens described in Embodiment 1. The excitation light path 39 includes:

[0065] The excitation light unit 41 is used to generate excitation original light;

[0066] A collimating lens 42, used for converting the excitation original light generated by the optical exciter into excitation parallel light;

[0067] A first filter, used for filtering the excitation parallel light converted by the collimating lens 42 to obtain monochromatic excitation light;

[0068] The dichroic mirror 43 is used to reflect the excitation light onto the test tube on the sample platform 51.

[0069] Embodiment 5: This embodiment further limits the multi-channel fluorescence detection system for foodborne pathogens described in Embodiment 1. The detection optical path includes:

[0070] The second filter 45 is used to filter the detection parallel light emitted by the excitation light path to obtain monochromatic detection parallel light;

[0071] A second focusing lens 46 is used to focus the monochromatic detection parallel light obtained after being filtered by the second filter 45;

[0072] The photodetector 47 is used to detect the monochromatic detection light focused by the second focusing lens 46.

[0073] Embodiment 6. This embodiment is a further limitation of the multi-channel fluorescence detection system for foodborne pathogens described in embodiment 4. The axis of the collimating lens 42 and the axis of the first focusing lens 44 are perpendicular to each other, and the angles between the dichroic mirror 43 and the axis of the collimating lens 42 and the axis of the second focusing lens 46 are all 45°.

[0074] Embodiment 7: This embodiment further limits the multi-channel fluorescence detection system for foodborne pathogens described in Embodiment 1, and the switching motor is a stepping motor 32 .

[0075] Embodiment 8. This embodiment is a further limitation of the multi-channel fluorescence detection system for foodborne pathogens described in Embodiment 7. The stepper motor 32 is also provided with a first pulley 33, a belt 35 and a second pulley 37. The first pulley 33 is arranged on the stepper motor 32, and one end of the belt 35 is sleeved on the first pulley 33, and the other end is sleeved on the second pulley 37.

[0076] Embodiment 9. This embodiment further limits the multi-channel fluorescence detection system for foodborne pathogens described in embodiment 1. A first optical detection unit support frame 25 and a second optical detection unit support frame 26 are also provided on the base 3 for supporting the optical detection unit 34.

[0077] Embodiment 10: This embodiment proposes a multi-channel fluorescence detection method using a multi-channel fluorescence detection system for foodborne pathogens as described in any one of embodiments 1 to 9, comprising the following steps:

[0078] S1. After the power is supplied, the touch display screen 5 lights up and selects the operation to be performed;

[0079] S2, put the sample platform 51 into the detection system, touch the display screen 5 to start detection, the stepper motor 32 drives the sample platform 51, and rotates the test tube to the specified position; the photoelectric detection unit emits excitation light to illuminate the sample platform 51, excites the fluorescence in the sample platform 51, and the fluorescence is transmitted to the main control module for processing through the signal acquisition and processing module; the photoelectric detection unit repeats the above operation;

[0080] S3, based on S2, the fluorescence imaging unit 14 performs image acquisition and data processing, and after completion, the stepper motor rotates to make the second test tube slot 54 reach the preset position, and continue the above operations;

[0081] S4. After the sample platform 51 rotates eight times, eight rounds of photoelectric acquisition and image acquisition are completed, and finally the concentration information and image information of the sample foodborne pathogens are displayed on the touch display screen 5.

[0082] Implementation method 11: See Figures 1 to 22 This embodiment is described. This embodiment provides an example, which is used to explain the above-mentioned embodiments 1 to 10. The specific example is as follows:

[0083] The multi-channel fluorescence detection system described in this embodiment is generally referred to as Figure 1 As shown, the system includes a housing 1, a flip cover 2, a base 3, and a fixed shaft 4; the housing 1 and the flip cover 2 are fixed by the fixed shaft 4;

[0084] The structural diagram of the housing 1 is shown in FIG. Figure 2 As shown, it includes a touch display screen 5, a first flip cover positioning hole 6, a second flip cover positioning hole 7, a fixed shaft jack 8, a lead hole 9, and a sample injection detection hole 10;

[0085] In order to reduce the complexity of the multi-channel fluorescence detection system, a touch screen 5 is used to reduce the use of buttons, and all operations can be performed on the screen; the lead hole 9 is reserved for subsequent fluorescence imaging detection; the injection detection hole 10 is prepared for the injection platform, which can be used for sample removal or placement and detection operations;

[0086] Flip 2, as Figure 3 As shown, it mainly includes 11 a first flip cover positioning buckle, 12 a second flip cover positioning buckle, and 13 a fluorescence imaging unit positioning slot. The fluorescence imaging unit 14 is as shown Figure 4 As shown, it mainly includes a CMOS sensor 15, a filter card slot 16, a ring-shaped LED light source 17, and a fluorescent imaging unit circuit board 18;

[0087] Among them, CCD and CMOS sensors are the most common photosensors at present. CCD needs three different power supplies to cooperate under the control of synchronous signals to output and transfer charge information. The whole circuit is relatively complex and slow. CMOS sensors directly generate current or voltage signals after photoelectric conversion. Signal reading is very simple. It can also process the image information of each unit at the same time, and the speed is much faster than CCD. CMOS sensors use the most commonly used CMOS process for general semiconductor circuits. The peripheral circuits can be easily integrated into the sensor chip, thus saving the cost of peripheral chips. The cost is relatively lower than that of CCD, so CMOS cameras are used to process fluorescent imaging units;

[0088] The filter slot 16 is used to place a filter to eliminate interference caused by the excitation light; the filter can be switched according to the different fluorescent dyes used;

[0089] The annular LED light source 17, the fluorescence detection system described in the present invention selects to use an LED light source instead of a laser light source. Compared with the solid laser light source in the prior art, the LED light source is small in size, low in cost, stable in performance, and more convenient to drive.

[0090] The CMOS sensor 15 , the filter slot 16 and the annular LED light source 17 are located on the same center line.

[0091] The side view of the fluorescence imaging unit 14 is as follows Figure 5 As shown, the annular LED light source support column 19, the filter placement position 20, and the fluorescent imaging unit LED 21; the flip cover 2 and the fluorescent imaging unit 14 are assembled as shown in FIG. Figure 6 shown.

[0092] The base 3 is as Figure 7 , including a circuit board placement position 22, a circuit board support column 23, a stepper motor placement slot 24, a first optical detection unit support frame 25, a second optical detection unit support frame 26, and an optical detection unit support column 27. The side view is shown in FIG. Figure 8 The first optical detection unit support frame 25 has a first optical detection unit lead hole 28 and a first crawler conveying channel 30, and the second optical detection unit support frame 26 has a second optical detection unit lead hole 29 and a second crawler conveying channel 31; the base 3 and the circuit board 31, the stepper motor 32, the first pulley 33, the optical detection unit 34, and the belt 35 are installed in an assembly as shown in FIG. Fig. 9 As shown;

[0093] The four circuit board positioning holes 36 of the circuit board 31 pass through the four circuit board support columns 23 respectively and are installed above the circuit board placement position 22. The purpose of the circuit board support columns 23 is to suspend and fix the circuit board 31 and prevent component loss; the circuit board positioning holes 36 are as follows: Fig.10 shown.

[0094] Fig.11 As shown, the second pulley 37 is inserted into the support column of the optical detection unit 27, and then inserted into the sample platform 51 after the optical detection unit 34 is inserted;

[0095] Fig.12 As shown, the first pulley 33 is inserted into the stepper motor 32, and is connected to the second pulley 37 through the belt 35. The rotation of the stepper motor 32 drives the first pulley 33 to rotate, thereby driving the belt 35 to rotate and then driving the second pulley 37 to rotate, thereby driving the sample platform 51;

[0096] Since the stepper motor 32 generates vibration when rotating, directly inserting it into the sample platform 51 may cause the sample to be unstable, thereby affecting the measurement accuracy. Therefore, a first pulley 33, a belt 35 and a second pulley 37 are installed to ensure the stability of the optical detection unit 34 when the stepper motor 32 drives the sample platform 51.

[0097] Fig.13 As shown, the bottom of the optical detection unit 34 overlaps with the support frame of the second optical detection unit 26 , and the side surface overlaps with the support frame 25 of the first optical detection unit. The optical detection unit 34 is embedded in the support frame 25 of the first optical detection unit.

[0098] The optical detection unit 34 is in a four-leaf clover shape, which saves space utilization and is supported by four fixed columns around it, making the structure more stable. The optical detection unit 34 is composed of four identical parts, wherein the first optical detection unit 38 is as shown in FIG. Fig.14 As shown, when in normal use, the sample platform 51 is placed in the optical detection unit 34, and the stepper motor 32 controls the sample platform 51 to rotate so that it can perform different channel detections. The optical path structure is as shown in FIG. Fig.15 As shown, it includes an excitation light path 39 for generating excitation light and allowing the excitation light to enter the sample platform 51, and an emission light path 40 for detecting the detection light emitted after reflection.

[0099] See also Fig.16 As shown, the emission light path 40 includes an excitation light unit 41, which is usually an LED, a collimating lens 42, a dichroic mirror 43, a first focusing lens 44, a second filter 45, a second focusing lens 46, and a photodetector 47, which is usually a photodiode.

[0100] The excitation light unit 41 usually selects LED. As a cold light source, LED has the advantages of fast response speed, stable intensity, low energy consumption, and good monochromaticity. Therefore, the excitation light source of this system selects LED light source. The specific selection needs to be determined according to the excitation wavelength of the fluorescent dye used. The collimating lens 42 is used to convert the excitation light generated by the excitation light unit 41 into excitation parallel light; the collimating lens 42 includes a first filter for filtering the excitation parallel light obtained by the collimating lens conversion to obtain monochromatic excitation light. The dichroic mirror 43 plays a reflective role, so that the excitation light is fully projected onto the test tube in the sample platform 51. The second focusing lens 46 is used to focus the emission light reflected by the dichroic mirror 43.

[0101] The second filter 45 is used to filter the detection parallel light excited by the incident light to obtain the monochromatic detection parallel light. The second focusing lens 46 is used to focus the monochromatic detection parallel light obtained after being filtered by the second filter 45. The photodetector 47 is used to detect the monochromatic detection light focused by the second focusing lens 46;

[0102] When incident light shines on the bacterial colony marked with fluorescent dye, the atoms in the fluorescent dye that were originally in the ground state transition to the excited state, generating fluorescence with a longer wavelength than the incident light, which is eventually collected by a photodetector. A photodetector is a device that converts fluorescent signals into electrical signals based on the photoelectric effect. Currently, the photoelectric conversion devices commonly used for fluorescence signal detection include photomultiplier tubes (PMTs), photodiodes (PDs), and charge-coupled devices (CCDs).

[0103] The excitation light unit generates excitation light, which passes through a collimating lens and a filter, is reflected on a dichroic mirror, passes through an excitation light path focusing lens, and finally irradiates the test tube in the sample wheel. After exciting the emission light of the fluorescent dye in the test tube, the emission light passes through a filter and an emission light path focusing lens, and finally reaches a photodetector.

[0104] The excitation light path 39 intersects the emission light path 40 at right angles, the axis of the collimating lens 42 and the axis of the first focusing lens 44 are perpendicular to each other, and the angles between the dichroic mirror 43 and the axis of the collimating lens 42 and the axis of the second focusing lens 46 are all 45°.

[0105] The four optical detection parts are exactly the same, and the excitation light paths and emission light paths of the four channels are also exactly the same. The configuration can be changed according to the different fluorescent dyes. The light-emitting circuit includes an excitation light unit 41, usually an LED, a collimating lens 42, a dichroic mirror 43, a first focusing lens 44, a second filter 45, a second focusing lens 46, a photodetector 47, usually a photodiode and a CMOS sensor 15 in the fluorescence imaging unit 14, a filter, and a ring-shaped LED light source 17. By rotating the stepper motor, switching between different detection channels and different samples can be achieved, so that different fluorescence detection channels can simultaneously realize fluorescence detection of the samples to be tested, which can effectively improve the detection efficiency.

[0106] The exploded view of the optical detection unit 34 is as follows: Fig.17 , wherein the optical detection unit includes a first optical detection unit 38, a second optical detection unit 48, a third optical detection unit 49, a fourth optical detection unit 50, a sample platform 51, and a sample platform cover 52;

[0107] The first optical detection unit 38, the second optical detection unit 48, the third optical detection unit 49, and the fourth optical detection unit 50 are completely identical; 8 sample tubes can be inserted into the sample platform 51 for detection at the same time;

[0108] Fig.18 Middle sample platform 51, sample platform cover plate 52, first test tube slot 53, second test tube slot 54, fluorescence imaging detection hole 55, eighth test tube slot 56, cover plate pull rod 57;

[0109] The sample platform cover 52 can completely cover the sample platform 51, and the two structures are coaxial; when the optical detection unit 34 is assembled, the fluorescence imaging detection hole 55 is coaxial with the first test tube slot 53, so that the substance in the test tube inserted into the test tube slot is fluorescently imaged. During the detection process, when the stepper motor 32 drives the sample platform 51 to rotate clockwise, the fluorescence imaging detection hole 55 will be coaxial with the second test tube slot 54, and continue to perform fluorescence imaging on the substance in the test tube inserted into the test tube slot, and so on, until the fluorescence imaging detection hole 55 is coaxial with the eighth test tube slot 56, and the detection is completed; the cover pull rod 57 is used to facilitate the placement and removal of the sample platform 52 cover; tweezers can be used when inserting or removing the sample tube; the optical detection unit 34 can be disassembled or assembled when disassembling the sample platform 51.

[0110] When the fluorescence imaging unit 14 detects Fig.19 As shown, the fluorescence imaging unit 14 is located above the cover of the sample platform 52, and the annular LED light source 17 is coaxial with the fluorescence imaging detection hole 55;

[0111] Detection optical path Fig. 20As shown; it includes a CMOS sensor 15, a ring LED light source 17, a sample tube 58, a fluorescence imaging unit filter 59, an excitation light path of a fluorescence imaging unit 60, and an emission light path of a fluorescence imaging unit 61;

[0112] Specifically, the fluorescence imaging unit LED21 on the annular LED light source 17 emits excitation light to excite the fluorescent dye in the test tube to emit emission light, and then the emission light passes through the fluorescence imaging unit filter 59 to eliminate the interference caused by the excitation light and is received by the CMOS sensor 15 to realize the fluorescence imaging function.

[0113] Specifically, the housing 1, the flip cover 2, the base 3, the fixed shaft 4; after being assembled with other modules, Fig.21 shown.

[0114] The specific block diagram of the circuit board 31 is as follows: Fig. 22 As shown, specifically: after the power is supplied, the touch display screen 5 lights up, and the operation to be performed is selected; the sample is placed in the detection device, and the detection is started. The stepper motor 32 drives the sample platform 51 to rotate the test tube to a preset position; the photoelectric detection unit LED1 emits an excitation light to illuminate the sample, excites the fluorescence in the sample, and the fluorescence is transmitted to the main control module for processing through the signal acquisition and processing module; sequentially, the photoelectric detection units LED2, 3, and 4 repeat the same operation. After a round of photoelectric detection is completed, the fluorescence imaging unit 14 performs image acquisition and data processing. After completion, the stepper motor rotates to make the second test tube slot 54 reach the specified position, and continue the above operation; after eight rotations, eight rounds of acquisition are completed, and finally the sample foodborne pathogen concentration information and image information are displayed on the touch display screen 5.

[0115] In summary, this embodiment provides a multi-channel fluorescence detection system for foodborne pathogens; it can detect multiple pathogens at the same time, with high detection efficiency. It combines photoelectric detection method and fluorescence imaging detection method to improve detection accuracy and observe image information in real time.

[0116] In this embodiment, the 3D printing material is resin, and other printing materials can be used; and common excitation light sources can include mercury lamps, xenon lamps, lasers, light-emitting diodes, etc.; photoelectric conversion devices mainly include photomultiplier tubes PMT, photodiodes PD and charge-coupled devices CCD, etc.; image sensors can use CCD cameras or CMOS cameras; the current design system is four-channel, channels can be increased or reduced, and the channel configuration remains unchanged; and the injection wheel is currently designed for 8-sample injection, sample grooves can be increased or reduced, and the rest of the configuration remains unchanged.

[0117] Those skilled in the art will appreciate that the above are only preferred embodiments of the present invention, and the various embodiments of the present disclosure and / or the features described in the claims may be combined or combined in various ways, even if such combinations or combinations are not explicitly described in the present disclosure. It is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art may still modify the technical solutions described in the aforementioned embodiments, or perform equivalent substitutions on some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

[0118] Although preferred embodiments of the present invention have been described, additional changes and modifications may be made to these embodiments by those skilled in the art once the basic inventive concepts are known. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A multi-channel fluorescence detection system for foodborne pathogens, characterized in that: The multi-channel fluorescence detection system comprises a housing (1), a flip cover (2), a base (3), and a fixed shaft (4); the housing (1) and the flip cover (2) are fixed to the base (3) via the fixed shaft (4); a fluorescence imaging unit (14) is provided on the flip cover (2) for processing image information of a sample solution in a sample platform (51); an optical detection unit (34) is provided on the base (3) for performing fluorescence detection on a sample platform (51) to be detected; the sample platform (51) is controlled to rotate by a switching motor (32) so that detection of different channels is performed; The optical detection unit (34) comprises an excitation light path (39) for generating excitation light and allowing the excitation light to enter the sample platform (51) and formed, and an emission light path (40) for detecting the detection light emitted after reflection.

2. The multi-channel fluorescence detection system for foodborne pathogens according to claim 1, characterized in that: The fluorescence imaging unit (14) comprises a CMOS camera (15), a filter slot (16), an annular LED light source (17), and a fluorescence imaging unit circuit board (18); the CMOS camera (15), the filter slot (16), and the annular LED light source (17) are located on the same center line.

3. The multi-channel fluorescence detection system for foodborne pathogens according to claim 1, characterized in that: The optical detection unit (34) is in a four-leaf clover shape, and comprises a first optical detection unit, a second optical detection unit, a third optical detection unit, and a fourth optical detection unit, and the four optical detection units are completely identical.

4. The multi-channel fluorescence detection system for foodborne pathogens according to claim 1, characterized in that: The excitation optical path (39) comprises: An excitation light unit (41), used for generating excitation original light; A collimating lens (42) is used to convert the original excitation light generated by the light exciter into parallel excitation light; A first filter, used for filtering the excitation parallel light converted by the collimating lens (42) to obtain monochromatic excitation light; The dichroic mirror (43) is used to reflect the excitation light onto the test tube of the sample platform (51).

5. The multi-channel fluorescence detection system for foodborne pathogens according to claim 1, characterized in that: The detection optical path comprises: A second filter (45) is used to filter the detection parallel light emitted by the sample excited by the excitation light path to obtain monochromatic detection parallel light; A second focusing lens (46) is used to focus the monochromatic detection parallel light obtained after being filtered by the second optical filter (45); A photodetector (47) is used to detect the monochromatic detection light focused by the second focusing lens (46).

6. The multi-channel fluorescence detection system for foodborne pathogens according to claim 4, characterized in that: The axis of the collimating lens (42) and the axis of the first focusing lens (44) are perpendicular to each other, and the angles between the dichroic mirror (43) and the axis of the collimating lens (42) and the axis of the second focusing lens (46) are all 45°.

7. The multi-channel fluorescence detection system for foodborne pathogens according to claim 1, characterized in that: The switching motor is a stepping motor (32).

8. The multi-channel fluorescence detection system for foodborne pathogens according to claim 7, characterized in that: The stepper motor (32) is further provided with a first pulley (33), a belt (35) and a second pulley (37); the first pulley (33) is arranged on the stepper motor (32); one end of the belt (35) is sleeved on the first pulley (33) and the other end is sleeved on the second pulley (37).

9. The multi-channel fluorescence detection system for foodborne pathogens according to claim 1, characterized in that: The base (3) is also provided with a first optical detection unit support frame (25) and a second optical detection unit support frame (26) for supporting the optical detection unit (34).

10. A multi-channel fluorescence detection method using the multi-channel fluorescence detection system for foodborne pathogens according to any one of claims 1 to 9, characterized in that: The steps include: S1. After the power is supplied, the touch display screen (5) lights up and the operation to be performed is selected; S2, placing the sample platform (51) into the detection system, touching the display screen (5) to start detection, the stepping motor (32) drives the sample platform (51) to rotate the test tube to a specified position; the photoelectric detection unit emits excitation light to illuminate the sample platform (51), exciting fluorescence in the sample platform (51), and the fluorescence is transmitted to the main control module for processing via the signal acquisition and processing module; The photoelectric detection unit repeats the above operation; S3, based on S2, the fluorescent imaging unit (14) performs image acquisition and data processing, and after completion, the stepper motor rotates to make the second test tube slot (54) reach a preset position, and continues the above operation; S4. After the sample platform (51) rotates eight times, eight rounds of photoelectric acquisition and image acquisition are completed, and finally the concentration information and image information of the sample foodborne pathogens are displayed on the touch display screen (5).

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