MOF (Metal Organic Framework)-based colorimetric sensor, equipment and method for detecting pathogenic microorganism infection of meat

Abstract

The invention discloses an MOF-based colorimetric sensor, equipment and a method for detecting pathogenic microorganism infection of meat, and belongs to the technical field of meat detection.The MOF-based colorimetric sensor comprises two transparent breathable layers and a detection layer used for making contact with organic compounds volatilized by a to-be-detected sample; the detection layer is arranged between the two transparent breathable layers; the detection layer takes a PVDF (Polyvinylidene Fluoride) film as a substrate; the substrate is coated with a plurality of MOF (Metal Organic Framework)-dye mixtures; the MOF-dye mixture is an MOF material loaded with a dye. According to the invention, the dye is loaded on the MOF material, through the characteristic of high specific surface area of the MOF material, the contact efficiency of the dye and pathogenic microorganisms for producing VOCs through metabolism is obviously enhanced, and the chromogenic reaction degree of the dye after the dye is in contact with the VOCs is improved to a certain extent; in addition, an MOF-dye mixture is coated on the PVDF film to reduce the interference of humidity on the detection result, so that the detection stability of the beef in complex environments such as storage, transportation and the like is ensured.

Description

Technical Field

[0001] This invention relates to the field of meat testing technology, specifically to a MOF-based colorimetric sensor, device, and method for detecting pathogenic microorganisms in meat. Background Technology

[0002] Beef, a widely consumed and highly nutritious meat, is directly affected by pathogenic microorganism contamination, impacting consumer safety and health. Traditional detection methods are limited by their cumbersome operation, time-consuming nature, and reliance on specialized equipment and personnel, failing to meet the needs for rapid on-site screening of beef during production, transportation, and sales, and hindering timely control of food safety risks. Therefore, the use of a rapid and accurate detection device is crucial. Colorimetric sensor technology, with its advantages of visualization, no need for complex instruments, and rapid response, has become a breakthrough in the rapid detection of pathogenic beef. Its core principle is to trigger color changes through the specific interaction of the sensing material with the metabolic products of pathogenic microorganisms, enabling result interpretation without complex operations or large instruments.

[0003] However, existing colorimetric sensors suffer from drawbacks when detecting pathogenic beef, including narrow color change range of a single dye, poor signal stability, and interference from moisture and oils volatilized during beef storage. Furthermore, traditional colorimetric sensor fabrication methods have limited sensitivity for detecting low concentrations of biogenic amines, making it difficult to capture early contamination signals in beef. In addition, existing colorimetric sensors are mostly laboratory-grade distributed devices with the following problems: low sensor integration; shallow color development when detecting low concentrations of volatile organic compounds (VOCs) produced by pathogenic microorganisms, making subtle color changes difficult to discern with the naked eye and easily leading to missed or misjudged results; moisture and oils volatilized during beef storage alter the detection environment, interfering with the sensor's color development signal and reducing detection accuracy; limited reusability, with most being single-use designs requiring re-fabrication after each use, resulting in material waste and increased detection time and cost; moisture easily penetrating the detection layer and affecting the dye reaction; and waterproof designs would block VOCs from contacting the sensor, further affecting detection stability. Therefore, these limitations restrict the application of these sensors in complex scenarios.

[0004] Therefore, developing a reusable colorimetric sensor detection device is of great significance for reducing food safety risks and waste in meat products. Summary of the Invention

[0005] The purpose of this invention is to provide a MOF-based colorimetric sensor for detecting pathogenic microorganisms in meat, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions: A MOF-based colorimetric sensor for detecting pathogenic microorganisms in meat comprises two transparent and breathable layers and a detection layer for contacting organic compounds volatilized from the sample to be tested; the detection layer is disposed between the two transparent and breathable layers; the detection layer is based on a PVDF membrane; a mixture of various MOF-dyes is coated on the substrate; the MOF-dye mixture is a MOF material loaded with dyes.

[0007] Furthermore, the transparent and breathable layer is made of porous transparent plastic material.

[0008] Furthermore, the MOF material is ZIF-8.

[0009] Another object of the present invention is to provide a device for detecting pathogenic microorganisms in meat, including a detection module, the detection module including a gas chamber and the above-mentioned MOF-based colorimetric sensor; the MOF-based colorimetric sensor is disposed in the gas chamber.

[0010] Furthermore, the equipment for detecting pathogenic microorganisms in meat also includes: An image acquisition module is used to acquire the colorimetric image of the MOF-based colorimetric sensor; An image processing module is used to analyze the colorimetric image to identify pathogenic microorganisms.

[0011] Furthermore, the detection module also includes: An adjustable baffle is used to close the air chamber; A container for holding the sample to be tested is disposed within the gas chamber; A trachea is used to introduce or expel inert gas into the gas chamber.

[0012] Another object of the present invention is to provide an application of the above-described MOF-based colorimetric sensor or the above-described device in the detection of pathogenic microorganisms in meat.

[0013] Another object of the present invention is to provide a method for detecting pathogenic microorganisms in meat for non-diagnostic purposes, based on the above-mentioned equipment, which includes the following steps: The sample to be tested is placed in the gas chamber, and the gas chamber is then sealed. An inert gas is introduced into the gas chamber so that the organic compounds volatilized from the sample come into contact with the MOF-based colorimetric sensor and undergo a colorimetric reaction. Acquire the colorimetric image of the MOF-based colorimetric sensor; The colorimetric images are analyzed to identify pathogenic microorganisms; Further, the step of analyzing the colorimetric image to identify pathogenic microorganisms specifically includes: Based on the pre-trained YOLOv8 segmentation model, the color image is segmented into several independent color matrix sub-images; Extract sub-image features from the color matrix sub-image; Based on a pre-trained YOLOv8 classification model, input subgraph features and output the corresponding pathogenic microorganism category and confidence level; Several independent color matrix sub-images are matched one by one with the pathogenic microorganisms to generate a test report.

[0014] Furthermore, the method for detecting pathogenic microorganisms in meat also includes: after the detection is completed, opening the gas chamber and introducing inert gas into the gas chamber for washing, so that the MOF-based colorimetric sensor returns to its initial state.

[0015] This invention loads dye onto MOF material. By utilizing the high specific surface area of ​​MOF material, the contact efficiency between the dye and VOCs generated by pathogenic microorganisms is significantly enhanced, thereby improving the degree of colorimetric reaction of the dye after contact with VOCs to a certain extent. In addition, this invention reduces the interference of humidity on the detection results by coating the MOF-dye mixture onto a PVDF membrane, ensuring the detection stability of beef under complex environments such as storage and transportation.

[0016] The MOF-based colorimetric sensor for detecting pathogenic microorganisms in meat provided by this invention employs an assembly method of two transparent and breathable layers sandwiching a PVDF membrane. This method can fabricate a MOF-based colorimetric sensor that combines waterproof, breathable, and transparent properties, thereby effectively avoiding interference from humidity on the detection results. At the same time, a structured detection module is designed to integrate the MOF-based colorimetric sensor array, enabling the sensor to be adapted to the image acquisition and processing module, forming a complete detection device that meets the needs of rapid on-site detection and has good commercial prospects. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the MOF-based colorimetric sensor for detecting pathogenic microorganisms in meat provided in an embodiment of the present invention.

[0018] Figure 2 This is a schematic diagram of the structure of the equipment for detecting pathogenic microorganisms in meat provided in an embodiment of the present invention.

[0019] Figure 3 This is a schematic diagram of the detection module provided in an embodiment of the present invention.

[0020] Figure 4 This is a schematic diagram of the colorimetric image segmentation process in the meat pathogen infection detection method provided in this embodiment of the invention.

[0021] Figure 5This is a flowchart illustrating the classification of pathogenic microorganisms in the meat pathogen infection detection method provided in this embodiment of the invention.

[0022] In the diagram: 1. Box; 2. Image processing module; 3. Image acquisition module; 4. Detection module; 401. Container; 402. Air tube; 403. Air chamber; 404. Colorimetric sensor array; 405. Baffle; 4041. Transparent and breathable layer; 4042. Substrate; 4043. MOF-dye mixture. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] Currently, when meat products are infected by pathogenic microorganisms, the metabolic process of these microorganisms produces unique volatile organic compounds (VOCs). For example, Staphylococcus aureus metabolism produces isovaleric acid and furfuryl formate, among other VOCs. The content of these VOCs is highly correlated with the degree of infection. The accumulation of VOCs promotes the reaction of MOF-dyes with these VOCs, resulting in a colorimetric reaction and thus enabling the visualization of pathogenic microorganism infection in meat. However, during storage, meat products experience the volatilization of moisture and oils, which can cause the dissolution or reaction of gaseous analytes, thereby affecting the detection sensitivity of colorimetric sensors.

[0025] In the detection of pathogenic microorganisms in beef, this invention addresses the problems of low integration and light color development that are difficult to distinguish with the naked eye in existing colorimetric sensors, and enhances their detection capabilities in complex environments.

[0026] Specifically, such as Figure 1 As shown, in one embodiment of the present invention, a MOF-based colorimetric sensor for detecting pathogenic microorganisms in meat is provided, comprising two transparent and breathable layers 4041 and a detection layer for contacting organic compounds volatilized from the sample to be tested; the detection layer is disposed between the two transparent and breathable layers 4041; the detection layer is based on a PVDF membrane 4042; a variety of MOF-dye mixtures 4043 are coated on the substrate 4042; the MOF-dye mixture 4043 is a MOF material loaded with dyes.

[0027] It should be noted that the MOF-dye mixture 4043 can be of various types, and can be made from dyes of different colors and MOF materials. Different types of dyes react with VOCs produced by the metabolism of pathogenic microorganisms to produce different color development results. In the embodiments of the present invention, nine types of MOF-dye mixture 4043 are provided for illustrative purposes, but are not limited thereto.

[0028] This invention, through the aforementioned MOF-based colorimetric sensor, enables the visualization of detection results, leveraging the high specific surface area of ​​MOF materials to enhance these results. In practical applications, the detection results of the MOF-based colorimetric sensor can be captured using an industrial camera, and machine learning algorithms can be employed to distinguish different color matrices to identify pathogenic bacteria infecting beef. The MOF-based colorimetric sensor provided by this invention enables reversible detection, extending its service life to a certain extent. The use of this MOF-based colorimetric sensor allows for the detection of pathogenic microorganisms in meat and provides effective real-time monitoring of such infections.

[0029] In a preferred embodiment of the present invention, the transparent breathable layer is made of porous transparent plastic material. Preferably, the transparent breathable layer is an acrylic plate with openings that are adapted to the size of the colorimetric unit, which facilitates the passage of VOCs generated by the metabolism of pathogenic microorganisms in meat, and facilitates real-time observation of color changes of the MOF-based colorimetric sensor and acquisition of colorimetric images from the MOF-based colorimetric sensor.

[0030] In a preferred embodiment of the present invention, the MOF material is ZIF-8. Utilizing the high specific surface area of ​​MOF materials (such as ZIF-8), VOCs generated by the metabolism of pathogenic microorganisms in meat are efficiently enriched, enhancing the specificity and sensitivity of the dye colorimetric reaction, and enabling different pathogenic microorganisms to correspond to unique colorimetric characteristics. It should be noted that, considering the impact of the detection reagents on food safety, this embodiment of the present invention utilizes non-toxic dyes (such as Congo Red, phenol red, bromophenol blue, bromocresol purple, bromocresol green, neutral red, methyl red, methyl orange, chlorophenol red, etc.) and obtains detection results without contacting the test sample by detecting VOCs generated by the metabolism of pathogenic microorganisms.

[0031] In a preferred embodiment of the present invention, the method for preparing the above-mentioned MOF-based colorimetric sensor includes the following steps: preparing a detection layer; assembling the transparent and breathable layer 4041 and the detection layer from bottom to top to form a MOF-based colorimetric sensor.

[0032] The steps for preparing the detection layer include: preparing the MOF-dye mixture; determining the coating area of ​​the MOF-dye mixture; and coating the MOF-dye mixture.

[0033] Specifically, in the step of determining the coating area of ​​the MOF-dye mixture: to obtain the best test results while occupying the smallest possible volume, a minimum coating area of ​​1cm × 1cm is adopted.

[0034] In the preparation steps of the MOF-dye mixture: the selected dye can undergo a reversible reaction to achieve an "on-off-on" color development mode; the dye is loaded into the pores of the MOF material through physical adsorption to form a MOF-dye composite material; the specific steps for preparing the MOF-dye mixture include: Take 10 mg of ZIF-8 powder, add 1 mL of ethanol to prepare a uniform dispersion, then add 20 mL of dye solution, and place the mixture in a magnetic stirrer. Stir at 200 rpm for 0.5 hours at room temperature (25°C). Let the stirred mixture stand until complete precipitation to obtain the MOF-dye mixture.

[0035] In the MOF-dye mixture coating process: 10 μL of the MOF-dye mixture dispersion was taken with a pipette and uniformly drop-coated onto the surface of the PVDF membrane. After coating, the prepared PVDF membrane was dried at room temperature for 1 hour. The drop-coating process was repeated three times to form a color matrix composed of nine MOF-dye mixtures. By coating the MOF-dye mixture onto the PVDF membrane, the waterproof properties of the MOF-based colorimetric sensor can be enhanced.

[0036] like Figure 2 and Figure 3 As shown, in another embodiment of the present invention, a device for detecting pathogenic microorganisms in meat is also provided, including a housing 1, an image processing module 2, an image acquisition module 3, and a detection module 4; the detection module 4 includes an air chamber 403 and a colorimetric sensor array 404 composed of the aforementioned MOF-based colorimetric sensors; the colorimetric sensor array 404 is disposed within the air chamber 403. The image acquisition module 3 is used to acquire the colorimetric images from the MOF-based colorimetric sensors; the image processing module 2 is used to analyze the colorimetric images to identify pathogenic microorganisms.

[0037] In practical applications, the image processing module 2 can be a computer, which uses an internally deployed machine learning algorithm to enhance the color rendering results that are difficult to observe with the naked eye into RGB images that are visible to the naked eye, and distinguish the pathogens that infect the beef by distinguishing different color matrices; the image acquisition module 3 can be an industrial camera, which is installed at the upper rear half of the housing 1, directly above the colorimetric sensor array 404, and is used to capture the detection results of the MOF-based colorimetric sensor and store the detection results as RGB images.

[0038] like Figure 3 As shown, in a preferred embodiment of the present invention, the detection module 4 is installed at the bottom of the housing 1, and further includes: An adjustable baffle 405 is used to close the air chamber 403; Container 401, used to hold the sample to be tested, is disposed inside the gas chamber 403; The air tube 402 is used to introduce or discharge inert gas into the air chamber 403, and is located on both sides of the upper end of the air chamber 403.

[0039] In this embodiment of the invention, during detection, the baffle 405 extends to the outside, and a small amount of inert gas is introduced into the gas tube 402 to fill the gas chamber. When the gas comes into contact with the dye in the MOF-based colorimetric sensor, the MOF-based colorimetric sensor presents the detection result through a color change. After the detection is completed, the baffle returns to its original position, and inert gas is continuously introduced for purging to restore the MOF-based colorimetric sensor to its original state.

[0040] In summary, the MOF-based colorimetric sensor provided in this embodiment of the invention features a waterproof structural design that effectively reduces interference from humidity on the colorimetric sensor array 404, enabling real-time detection of pathogenic microorganisms in meat. The addition of MOF material lowers the detection limit while significantly enhancing the colorimetric sensor's colorimetric response and greatly improving its tolerance under complex conditions, demonstrating promising development and commercial prospects.

[0041] In another embodiment of the present invention, a method for detecting pathogenic microorganisms in meat for non-diagnostic purposes is also provided, based on the above-described equipment, comprising the following steps: S1. Place the sample to be tested into the air chamber 403 and seal the air chamber 403; S2. Inert gas is introduced into the gas chamber 403 so that the organic compounds volatilized from the sample to be tested come into contact with the MOF-based colorimetric sensor and undergo a colorimetric reaction. S3. Obtain the colorimetric image of the MOF-based colorimetric sensor; the colorimetric image may be preprocessed such as image enhancement before proceeding to the next step; S4. Analyze the colorimetric image to identify pathogenic microorganisms; S5. After the test is completed, open the gas chamber 403 and introduce inert gas into the gas chamber 403 for rinsing, so that the MOF-based colorimetric sensor returns to its initial state.

[0042] like Figure 4 and Figure 5 In a preferred embodiment of the present invention, the step of analyzing the colorimetric image to identify pathogenic microorganisms, i.e., step S4, specifically includes: S41. Based on the pre-trained YOLOv8 segmentation model, the color image is segmented into several independent color matrix sub-images; S42. Extract sub-image features from the color matrix sub-image; S43. Based on the pre-trained YOLOv8 classification model, input subgraph features and output the corresponding pathogenic microorganism category and confidence level; S44. Match several independent color matrix sub-images with the pathogenic microorganisms one by one to generate a test report. Specifically, identify pathogenic microorganisms by comparing them with the "pathogen characteristic color" standard library, and finally output a test report containing the type of pathogenic microorganism and the infection status.

[0043] In practical applications, there are also nine color matrix sub-graphs corresponding to the nine MOF-dyes mixture 4043. The analysis steps in the above method mainly include segmentation and classification.

[0044] The segmentation stage is fundamental to the entire process. Its core is the precise extraction of nine independent color matrix sub-images from the original color image using the YOLOv8 segmentation model. After training with labeled samples, the YOLOv8 segmentation model can identify the boundary features of the color matrix, eliminate background interference, and output standardized sub-image regions. This stage achieves the isolation and purification of the target region, providing interference-free and uniformly sized input data for subsequent classification, and avoiding cross-contamination or the influence of background information on feature extraction.

[0045] The classification stage is crucial for mapping "color pathogens," performing feature analysis and category matching based on the features of the segmented sub-images. Specifically, color features such as the RGB mean and HSV parameters of the sub-images are extracted and input into a YOLOv8 classification model trained on a "color matrix pathogen label" dataset. The YOLOv8 model, based on the learned mapping rules, outputs the category and confidence score of the corresponding pathogenic microorganism. This stage transforms visualized color information into quantifiable pathogen categories, leveraging the YOLOv8 classification model's ability to learn specific color features to achieve a precise conversion from colorimetric results to detection conclusions.

[0046] In summary, the detection method provided by the embodiments of the present invention utilizes MOF-enhanced color development, modular and collaborative equipment, reversible sensor regeneration, and AI-assisted identification to achieve rapid, visualized, and reusable detection of pathogenic microorganisms in meat.

[0047] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification.

Claims

1. A MOF-based colorimetric sensor for detecting pathogenic microorganisms in meat, characterized in that, It includes two transparent and breathable layers and a detection layer for contacting the organic compounds volatilized from the sample to be tested; the detection layer is disposed between the two transparent and breathable layers; the detection layer is based on a PVDF membrane; the substrate is coated with a mixture of various MOF-dyes; the MOF-dye mixture is a MOF material loaded with dyes.

2. The MOF-based colorimetric sensor for detecting pathogenic microorganisms in meat according to claim 1, characterized in that, The transparent and breathable layer is made of porous transparent plastic.

3. The MOF-based colorimetric sensor for detecting pathogenic microorganisms in meat according to claim 1, characterized in that, The MOF material is ZIF-8.

4. A device for detecting pathogenic microorganisms in meat, comprising a detection module, characterized in that, The detection module includes a gas chamber and a MOF-based colorimetric sensor as described in any one of claims 1-3; the MOF-based colorimetric sensor is disposed in the gas chamber.

5. The equipment for detecting pathogenic microorganisms in meat according to claim 4, characterized in that, Also includes: An image acquisition module is used to acquire the colorimetric image of the MOF-based colorimetric sensor; An image processing module is used to analyze the colorimetric image to identify pathogenic microorganisms.

6. The equipment for detecting pathogenic microorganisms in meat according to claim 4, characterized in that, The detection module also includes: An adjustable baffle is used to close the air chamber; A container for holding the sample to be tested is disposed within the gas chamber; A trachea is used to introduce or expel inert gas into the gas chamber.

7. The application of an MOF-based colorimetric sensor as described in any one of claims 1-3, or the device as described in any one of claims 4-6, in the detection of pathogenic microorganisms in meat.

8. A method for detecting pathogenic microorganisms in meat for non-diagnostic purposes, implemented using the equipment described in any one of claims 4-6, characterized in that, Includes the following steps: The sample to be tested is placed in the gas chamber, and the gas chamber is then sealed. An inert gas is introduced into the gas chamber so that the organic compounds volatilized from the sample come into contact with the MOF-based colorimetric sensor and undergo a colorimetric reaction. Acquire the colorimetric image of the MOF-based colorimetric sensor; The colorimetric images are analyzed to identify pathogenic microorganisms.

9. The method for detecting pathogenic microorganisms in meat according to claim 8, characterized in that, The steps of analyzing the colorimetric image to identify pathogenic microorganisms specifically include: Based on the pre-trained YOLOv8 segmentation model, the color image is segmented into several independent color matrix sub-images; Extract sub-image features from the color matrix sub-image; Based on a pre-trained YOLOv8 classification model, input subgraph features and output the corresponding pathogenic microorganism category and confidence level; Several independent color matrix sub-images are matched one by one with the pathogenic microorganisms to generate a test report.

10. The method for detecting pathogenic microorganisms in meat according to claim 8 or 9, characterized in that, Also includes: After the test is completed, the gas chamber is opened and inert gas is introduced into the gas chamber for purging, so that the MOF-based colorimetric sensor returns to its initial state.

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