Multifunctional composite sensor device for food safety detection

Abstract

The utility model provides a multifunctional composite sensor device for food safety detection. The multifunctional composite sensor device comprises an open-end coaxial sensor, an electrochemical sensor / interdigital capacitance sensor and a temperature sensor which are compounded in a protective shell, wherein the open-end coaxial sensor is used for testing the dielectric constant of a substance, and is particularly used for detecting the main components, salinity, sugar degree and maturity of the substance and the microstructure and texture of a to-be-tested substance; the electrochemical sensor is used for detecting the freshness of substances, the proportion of main components, toxic and harmful trace elements or trace compounds, toxic and harmful bacteria and the like; the temperature sensor is used for detecting the actual temperature and the temperature change condition of the detected substance; the composite sensor device disclosed by the utility model has full-band multi-dimensional substance detection capability, and can be used for real-time detection and evaluation of food safety and food quality.

Description

Technical Field

[0001] The utility model relates to the technical field of food safety detection, in particular to a multifunctional composite sensor device for food safety detection. Background Art

[0002] Daily food can be divided into two categories: plant food and animal food. According to the similarity of food nutrients, food can be classified into five small categories: grains and potatoes, meat, eggs and milk, beans and their products, vegetables and fruits, and oils and nuts. Testing the safety and quality of these foods requires more than 100 professional instruments, which need to be operated by professionals and involve thousands of national standards. This is beyond the ability of any ordinary citizen. Even for professional institutions, it is not easy to test the safety and quality of all categories of food. According to relevant notices, the amount of food inspections organized and implemented by various regions and relevant departments is only 4 samples per thousand people per year. Among them, the amount of food sample inspections organized by provinces (autonomous regions and municipalities) mainly for pesticide and veterinary drug residues is not less than 2 samples per thousand people per year. For a medium-sized city with a population of one million, the country's food inspection capacity can only test 4,000 samples per year, and the amount of food inspections for pesticide and veterinary drug residues is only 2,000 samples per year. Other inspections can only be carried out through random inspections. This huge gap between food inspection capabilities and actual needs has left a huge gap, giving many illegal food production and operation units or individuals the opportunity to escape sanctions.

[0003] In addition to conventional food safety, the general public is also very concerned about the freshness, nutritional value and taste of food; in addition, whether the family's food preparation methods are safe and reasonable, and whether bad eating habits exist, these are rarely tested or cannot be tested at all even by professional testing and inspection institutions. Therefore, it is extremely meaningful to design a low-cost, easy-to-operate portable food testing device so that the general public can fully participate in the supervision of food safety and quality, and test and self-evaluate the daily food preparation process.

[0004] For portable food testing devices suitable for the general public, it is necessary to consider the use of the testing device in a non-laboratory environment. In addition to low cost, easy operation and portability, a basic requirement for food testing devices is that the detection should be non-destructive and safe. Electromagnetic testing is a powerful non-destructive testing method. After more than 100 years of development, electromagnetic non-destructive testing has developed many detection means and methods, which are widely used in the fields of machinery, metallurgy, medicine, food, geology, safety and materials science. It is possible to develop a simple and effective detection device by using full-band electromagnetic non-destructive testing for food. To this end, a multifunctional composite sensor device for food safety testing is proposed. Utility Model Content

[0005] In view of this, the embodiments of the present utility model hope to provide a multifunctional composite sensor device for food safety detection to solve or alleviate the technical problems existing in the prior art and at least provide a beneficial choice.

[0006] The technical solution of the embodiment of the utility model is implemented as follows: a multifunctional composite sensor device for food safety detection, comprising an open-end coaxial sensor, an electrochemical sensor / interdigital capacitance sensor and a temperature sensor composited inside a protective shell;

[0007] in:

[0008] The open-ended coaxial sensor is used to test the dielectric constant of a substance, specifically to detect the main components, salinity, sugar content, maturity, and microstructure and texture of the substance to be tested;

[0009] The electrochemical sensor / interdigital capacitance sensor is used to test the electrochemical impedance effect of a substance, specifically to detect the freshness of the substance to be tested, and to detect trace amounts of specific toxic and harmful substances;

[0010] The temperature sensor is used to detect the actual temperature and temperature change of the measured substance.

[0011] In some embodiments: the open-ended coaxial sensor is a high-frequency electrode, the electrochemical sensor / interdigital capacitance sensor is a low-frequency electrode, and the temperature sensor includes a temperature sensing electrode.

[0012] In some embodiments: the low-frequency electrode is any one of an interdigitated capacitance electrode or a pin-type electrode;

[0013] in:

[0014] The electrode end of the interdigital capacitance electrode is provided with a switching device 1, which is used to replace the interdigital capacitance probe at the electrode end;

[0015] The electrode end of the pin-type electrode is provided with a second adapter device for replacing the stainless steel needle probe.

[0016] In some embodiments: the number of the high-frequency electrodes is 1-3.

[0017] In some embodiments: the number of the low-frequency electrodes is 1-3.

[0018] In some embodiments, the high-frequency electrodes and the low-frequency electrodes are arranged in a cross-symmetric manner so that the noise cancellation circuit inside the electrodes can achieve the best effect.

[0019] In some embodiments: the probe of the temperature sensing motor is located in the middle of the high-frequency electrode probe and the low-frequency electrode probe.

[0020] The embodiment of the utility model has the following advantages due to the adoption of the above technical solution:

[0021] The composite sensor device of the utility model has multi-dimensional material detection capabilities and can be used for real-time detection and evaluation of food safety and food quality.

[0022] The above summary is for the purpose of description only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features of the utility model will be readily apparent by reference to the accompanying drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 Schematic diagram of the law of dielectric constant changing with frequency;

[0025] Figure 2 The relationship between the real part and the imaginary part of the complex dielectric constant of the electrochemical impedance spectroscopy as a function of frequency (Cole-Cole diagram);

[0026] Figure 3 This is a structural diagram of the high-frequency electrode of the utility model;

[0027] Figure 4 The low-frequency electrode of the utility model has structure 1 and structure 2;

[0028] Figure 5 This is the structural diagram of the practical temperature sensing electrode;

[0029] Figure 6 This is a schematic diagram of the structure of the composite sensor according to an embodiment of the utility model;

[0030] Figure 7 For this utility model Figure 6 Schematic diagram of the extension and retraction of the detection probe of the composite sensor;

[0031] Figure 8 For this utility model Figure 6 Schematic diagram of the specific arrangement of the middle electrode Figure 1 ;

[0032] Fig. 9 For this utility model Figure 6Schematic diagram of the specific arrangement of the middle electrode Figure 2 ;

[0033] Fig.10 For this utility model Figure 6 Schematic diagram of the specific arrangement of the middle electrode Figure 3 ;

[0034] Fig.11 It is a structural schematic diagram of the interdigital capacitance sensor of the utility model. DETAILED DESCRIPTION

[0035] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0036] It should be noted that the terms "first", "second", "symmetrical", "array", etc. are only used to distinguish between description and position description purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the definition of "first", "symmetrical", etc. can explicitly or implicitly include one or more of these features; similarly, when the quantity of certain features is not limited in the form of words such as "two" or "three", it should be noted that this feature also explicitly or implicitly includes one or more feature quantities;

[0037] In the present invention, unless otherwise clearly specified and limited, the terms such as "installation", "connection", "fixation" and the like should be understood in a broad sense; for example, it can be a fixed connection, a detachable connection, or an integral molding; it can be a mechanical connection, a direct connection, welding, or an indirect connection through an intermediate medium, or it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood based on the description and drawings combined with specific circumstances.

[0038] The embodiments of the present utility model are described in detail below with reference to the accompanying drawings.

[0039] Food is a non-metallic substance, and almost all foods are poor conductors of electricity. There are many types of food, and there are more than 1,500 common types of daily food. The detection of so many substances requires that the detection device can work in the full frequency band as much as possible, from about 1Hz to about 10GHz, spanning more than 3 decades of frequency, from electrostatic fields, low-frequency electromagnetic fields, to microwaves and millimeter waves. This requires that the sensors used in electromagnetic non-destructive testing can adapt well to such a wide spectrum.

[0040] For any single substance or mixed substance, the dielectric constant is its basic physical quantity, which reflects the ability of the substance to maintain charge and the degree of dissipation of external electromagnetic energy under the condition of an external electric field. The detection of the dielectric constant can reflect the basic composition of the substance, the proportion of each component, the moisture content, the salt content, etc. The detection of the dielectric properties of food can also determine the salt, sugar, maturity, softening, freshness, degree of corruption, and taste of the food. The start coaxial sensor and the vector network analyzer can be used in conjunction to measure the dielectric constant of the material in the frequency band from kHz to tens of GHz. This measurement method is widely used in laboratories for the analysis of the dielectric properties of materials, the monitoring of material composition changes and chemical reaction processes, but such a wide spectrum range of vector network analyzers is too expensive to be used in portable detection devices, and the measured data below 100MHz is not very stable.

[0041] In order to fill this gap in low-frequency detection, the plane scattered field (forked finger) capacitance method is introduced to test the dielectric constant of the material. Unlike the parallel plate capacitor measurement method, the plane scattered field capacitance does not require the sample to be processed. It can be directly probed into the sample for measurement and is easy to clean after measurement. It uses the plane capacitance formed between the thickness of adjacent plane metal electrodes, but this capacitance is usually very small. In order to increase the capacitance, the forked finger capacitance is often used. The principle of its measurement is: first measure the capacitance of the forked finger capacitance electrode in the air, and then insert it into the material to be tested. The material to be tested that contacts the electrode surface will change the electric field distribution on the electrode plane, thereby changing its capacitance. The difference between this capacitance and the capacitance in the air is related to the dielectric constant of the material to be tested. Based on these two measured values, the dielectric constant of the material to be tested can be inverted. This forked finger capacitance electrode is often used to determine the polarized components (TPM: Total Polar Meterials) in edible oil after frying.

[0042] like Figure 1 As shown, Figure 1 The left shows the change of the biological dielectric constant (logarithmic coordinates) with the detection signal frequency (logarithmic coordinates). There are three obvious steps: the alpha step, the dielectric constant is very high, often thousands or tens of thousands, this involves the transport process of intercellular substances, generally occurs at a frequency of less than 1kHz (1ms); the beta step, the dielectric constant is hundreds or thousands, the corresponding signal frequency is from the kHz level to the 100MHz level, here involves the polarization of the components of the intercellular fluid and the intracellular fluid. The above is the case of living bodies. If the organism dies, its cell membrane will gradually disintegrate and decompose, the internal fluid of the cell will mix with the tissue fluid, and the various material components will undergo significant changes, which will be reflected in the dielectric constant of the substance.

[0043] Figure 1The right side shows the formation mechanism of the dielectric constant of a single substance.

[0044] Below 100kHz, the contribution of charged ions to the dielectric constant is due to polarization, and in the range of 1MHz-100GHz, it is due to the polarization of molecules. Above THz, it is due to the polarization of atoms.

[0045] As the frequency increases, the real part of the dielectric constant remains basically constant within a few hundred megahertz, and begins to decrease rapidly above GHz, reaching a few hundred gigahertz; the imaginary part of the dielectric constant usually decreases first and then increases, reaching a maximum value in the range of several GHz to tens of GHz; different substances can be distinguished by using the different laws of these changes.

[0046] For low frequency range, interdigitated capacitance electrodes have the potential to evolve into electrochemical electrodes. By applying a certain DC bias to the electrode and superimposing a small AC signal, the impedance spectrum (EIS) of the substance to be measured can be measured using this electrochemical electrode. The use of electrochemical impedance spectroscopy for the measurement of biological tissues or foods utilizes the capacitance effect caused by the cell membrane structure in biological tissues, namely the "cell membrane theory". Figure 2 A typical electrochemical impedance spectroscopy diagram shows the relationship between the real and imaginary parts of the dielectric constant as a function of frequency, also known as the Cole-Cole plot.

[0047] In the low frequency region of the impedance spectrum, mass transfer is dominant, while in the high frequency region, charge transfer is dominant. The low frequency range is generally 1mHz to 1kHz, and the high frequency range is generally 1kHz to 100kHz.

[0048] The electrochemical impedance spectroscopy is a frequency domain measurement method that regards the electrochemical process as a "black box" and uses an equivalent circuit to describe the behavior of this "black box" under external small signal excitation. Electrochemical impedance spectroscopy can be used to detect the freshness of fruits, vegetables, pork, and fish, and can also be used to detect pathogenic bacteria in food (such as E. coli). Its advantages are fast and timely detection, low cost, good repeatability, and simple detection circuit that is easy to implement in a portable manner.

[0049] After certain modification and activation of the metal on the surface of the electrochemical electrode, electrochemical analysis can be used to detect heavy metal elements in food (such as lead in liquor) and harmful ingredients in food, such as melamine content and aflatoxin in milk. It can also detect pesticides (isoprocarb) and veterinary drug residues (clenbuterol).

[0050] There are two types of electrochemical impedance spectroscopy (EIS) tests. One is based on the measurement of the capacity value. This measurement is relatively simple and does not involve any action or reaction between the electrode and the substance being tested. For example, the measurement of the polarization component TPM of oil products. The other is to activate the metal on the surface of the electrode to make it a catalyst for a certain reaction. The catalyst only works on a specific substance. Once a specific reaction occurs, the impedance will undergo a large change. According to the degree of change, it can not only determine whether a certain substance exists, but also detect the concentration of the substance through the size of the electrical parameters.

[0051] like Figure 3-11 As shown, the embodiment of the utility model provides a multifunctional composite sensor device for food safety detection, including an open-end coaxial sensor, an electrochemical sensor / interdigital capacitance sensor and a temperature sensor composited inside a protective shell;

[0052] in:

[0053] The open-end coaxial sensor is used to detect the main components, salinity, sugar content, maturity of the substance, and the microstructure and texture of the substance to be tested, and is used for high-frequency signal detection, wherein: 11 is a rigid coaxial cable, 12 is a detection end face of the open-end coaxial cable; 13 is an external thread of the detection end; 14 is an outer conductor of the coaxial cable; 15 is an inner conductor of the coaxial cable; 16 is a flexible coaxial cable; 17 is a rigid and flexible coaxial cable conversion interface; 19 is a sensor housing;

[0054] The electrochemical sensor / interdigital capacitance sensor is used to detect the freshness of the substance to be tested and to detect trace amounts of specific toxic and harmful substances, and is used for low-frequency signal detection, wherein: 21 is an interdigital capacitance form low-frequency sensor; 22 is an interdigital capacitance electrode; 23 is an electrode contact; 24 is a switching socket; 25 is an interdigital capacitance substrate; 26 is a low-frequency cable; 27 is a low-frequency cable interface; 29 is a sensor housing; 31 is a steel needle array form low-frequency sensor; 32 is a steel needle electrode array; 34 is a switching socket; 36 is a low-frequency cable; 37 is a low-frequency cable interface; 39 is a sensor housing;

[0055] The temperature sensor is used to detect the temperature of the substance to be measured, wherein: 41 is a temperature sensor; 42 is a temperature sensitive electrode (component); 43 is an electrode contact; 44 is a switching socket; 45 is a low-frequency cable housing; 46 is a low-frequency cable switching interface; 49 is a sensor housing;

[0056] The present application relates to a composite sensor device used in a portable detection device, wherein the composite sensor comprises at least a group of open-end coaxial sensors, a group of electrochemical sensors or an interdigital capacitance sensor, a temperature sensor, such as Figure 6As shown, 101 is a composite sensor; 111 is an open-end coaxial sensor; 112 is an interdigital capacitance sensor; 113 is a temperature sensitive sensor; 106 is a high-frequency and low-frequency composite cable; 107 is a composite cable conversion interface; 120 is a lever; and 121 is a lever sliding groove.

[0057] The composite sensor device combines an open-end coaxial sensor with an electrochemical sensor, which can perform a wide-band, multi-dimensional comprehensive detection of food. The open-end coaxial sensor is suitable for detecting the main components, salinity, sugar content, maturity, and microstructure and texture of the substance to be tested; while the electrochemical sensor can detect the freshness of the substance to be tested, and can specifically detect trace amounts of specific toxic and harmful substances. The temperature sensor can accurately detect the actual temperature of the substance to be tested. The dielectric properties and many other properties of the substance to be tested are closely related to the temperature. Before measurement, the sensor will be calibrated according to the actual temperature. The composite sensor device combining the above three sensors can be competent for the comprehensive identification and evaluation of common food safety and quality issues.

[0058] That is, the composite sensor device of the present application can also be composed of a high-frequency electrode, a low-frequency electrode and a temperature sensing electrode, and the specific process in which it is applied to detect is:

[0059] 1. Choose the appropriate composite sensor device according to the type of food to be tested and the testing requirements;

[0060] 2. Each independent sensor in the composite sensor device is calibrated separately. The calibration of the high-frequency electrode is carried out according to the OSL and ANA calibration methods of the open-end coaxial sensor. The calibration of the low-frequency electrode requires the simultaneous calibration of the real and imaginary parts of the impedance (calibration includes short-circuit calibration and open-circuit calibration. The short-circuit calibration of the low-frequency electrode is mainly to eliminate the influence of the residual impedance in series with the detection circuit and the electrode contact; the open-circuit calibration of the low-frequency electrode is mainly to eliminate the influence of the stray admittance in parallel with the test fixture and the device under test. For the test of capacitance, only open-circuit calibration can be performed); the high-frequency electrode must also be calibrated before use. Calibration includes calibration of the detection circuit port and calibration of the electrode itself. For the calibration method, see the patent "A method and device for rapid calibration of an open-end coaxial sensor". The calibration of the high-frequency and low-frequency electrodes is automatically controlled by an electronic switch;

[0061] 3. For higher frequencies above megahertz, a small high-frequency signal that is isolated from DC will be applied to the high-frequency electrode, and the high-frequency electrode will be inserted into the sample to a certain depth before detection begins. At this time, the detection device measures the S11 parameter of the detection end face of the open-end coaxial sensor. The dielectric constant of the material being tested can be calculated by inverting this parameter. Specifically, a small high-frequency signal that is isolated from DC will be applied to the high-frequency electrode, and the high-frequency electrode will be inserted into the sample to a certain depth before detection begins. This is achieved through a hardware circuit. At low frequencies, there is generally a DC bias, and then a small signal of several to tens of millivolts is superimposed on this DC bias; at high frequencies, a DC-isolating capacitor is used directly to isolate the DC signal, allowing only the high-frequency small signal to pass. When adding a bias at low frequencies, an RFC (high-frequency choke circuit) or a magnetic bead is usually used to prevent high-frequency signals from entering the DC power supply;

[0062] 4. For lower frequencies not exceeding MHz, a DC bias voltage and a millivolt-level AC small signal will be applied to the low-frequency electrode at the same time. The DC voltage is scanned within a certain frequency range to obtain the electrochemical impedance spectrum (EIS) of the object being measured and the dielectric constant at low frequency;

[0063] 5. Combine the low-frequency dielectric constant and the high-frequency dielectric constant. For the data with frequencies between the two, fit them according to the interpolation of the first two data segments.

[0064] The low-frequency electrode as described above can be an interdigital capacitance sensor (it can also be other forms of electrochemical sensors after the technology matures). The metal layer of the interdigital capacitor can be exposed or covered with a protective layer or a passivation layer. The base (substrate) of the interdigital electrode can be a certain ceramic material, glass or circuit board material (it can be a rigid circuit board such as FR-4 material, or a flexible circuit board such as polyimide PI or polyethylene terephthalate PET). Whether it is the electrode material, passivation layer material or substrate material, it should be food grade (in compliance with the national food safety standard GB4806 series), so that the sensor can be placed in food without posing a health risk. Its basic form is as follows: Fig.11 As shown, 1 is the interdigital capacitor electrode 1; 2 is the interdigital capacitor electrode 2; 3 is the contact (welding) point of the interdigital capacitor electrode 1; 4 is the contact (welding) point of the interdigital capacitor electrode 2; 5 is the interdigital capacitor substrate;

[0065] The high-frequency electrode is an open-ended coaxial sensor. The inner and outer conductors are exposed at the test end, and the electrode is an integral structure without any switching device, such as Figure 3 As shown;

[0066] There are two basic forms of low frequency electrodes, such as Figure 4 As shown:

[0067] One is an interdigital capacitance electrode, with a switching device at the end of the electrode, which can replace the interdigital capacitance probe at the end of the electrode;

[0068] The other is a pin-type electrode, which has a switching device at the end to allow the stainless steel needle probe to be replaced.

[0069] The basic dimensions of the above electrodes are the same, and the difference lies in the form of the probe. The probe can be replaced by plugging and unplugging the connector with the electrode.

[0070] The temperature sensing electrode can be in the form of a thermocouple or NTC thermistor. The algorithm is used to correct the nonlinearity of the thermocouple and NTC resistor with temperature change to ensure that the accuracy of temperature measurement is within + / -0.5 degrees Celsius. Its size is similar to the low-frequency and high-frequency electrodes above, such as Figure 5 As shown;

[0071] like Figure 6 As shown, the combination of the above electrodes is:

[0072] Basic combination form: a high-frequency electrode, a low-frequency electrode and a temperature sensing electrode combination, in which the high-frequency electrode is fixed and the low-frequency electrode can replace the probe type.

[0073] Extended combination form 1: a combination of two high-frequency electrodes, two low-frequency electrodes and one temperature sensing electrode;

[0074] Extended combination form 2: a combination of two high-frequency electrodes, one low-frequency electrode and one temperature sensing electrode;

[0075] Extended combination form 3: a combination of a high-frequency electrode, two low-frequency electrodes and a temperature sensing electrode;

[0076] Extended combination form 4: a combination of three high-frequency electrodes, three low-frequency electrodes and one temperature sensing electrode;

[0077] Combination of multiple electrodes:

[0078] The discrete electrode method is adopted. A set of data is obtained in one measurement, and multiple operations are required to obtain a complete measurement result. It is not optimal in detection efficiency, but the structure is simple and the cost is low.

[0079] By adopting the composite electrode method, the sensors of the composite probe cannot affect each other. In terms of structure, the mutual coupling (influence) between the sensors is minimal; during calibration, mutual coupling calibration is added, and after mutual coupling calibration, the mutual influence between the probes can be basically eliminated.

[0080] The composite electrode is not just a simple combination of multiple probes. The number and arrangement of probes should also be considered. The high-frequency probe and the low-frequency probe are arranged crosswise and symmetrically so that the detection circuit can reduce the noise of the detection signal. The symmetry of the probe position reduces the randomness of the detection data and enhances the detection ability of anisotropic materials. The temperature probe is located in the middle, and the temperature field here is equivalent to the average of the positions of several probes. The external protective shell protects the internal probe.

[0081] The composite probe is usually received inside the protective shell and equipped with a protective cover. When in use, the probe is pushed out with the lever. Press the reset button at the end to reset the probe.

[0082] Figure 7 The probe is an action structure. When testing, the lever 120 is pushed downward (rightward) along the lever sliding slot 121, and the sensor electrodes 111, 112, and 113 extend out of the sensor housing to start testing. After the test is completed and the electrodes are cleaned, the lever 120 is pushed back to the original position along the lever sliding slot, and the sensor electrodes 111, 112, and 113 are retracted into the sensor housing 101. In the non-testing state, the sensor housing 101 protects the sensor electrodes 111, 112, and 113.

[0083] like Figure 8 As shown, it is the basic combination form;

[0084] like Fig. 9 As shown, it is a combination of two high-frequency electrodes, two low-frequency electrodes and one temperature sensing electrode;

[0085] like Fig.10 As shown, it is a combination of three high-frequency electrodes, three low-frequency electrodes and one temperature sensing electrode;

[0086] Figure 8-10 In Chinese: HF = high frequency, indicating high frequency probe, LF = low frequency, indicating low frequency probe. The serial number behind indicates the number of multiple high frequency probes or low frequency probes. TC = temperature transducer, indicating temperature sensor or temperature probe, there is only one temperature probe.

[0087] When the utility model is working: the composite sensor device of the present invention includes an open-end coaxial sensor for testing the dielectric constant of a substance, and its applicable frequency range is generally tens of megahertz to tens of gigahertz; it also includes an electrochemical (interdigital capacitance) sensor for testing the electrochemical (capacitive) effect of a substance, and its applicable frequency range is a few tenths of a hertz to hundreds of kilohertz; it also includes a temperature sensor for detecting the actual temperature and temperature change of the substance being tested. The combination of these sensors enables the composite sensor device to have multi-dimensional material detection capabilities, and can be used for real-time detection and evaluation of food safety and food quality;

[0088] The multi-dimensionality refers to the fact that food evaluation has several dimensions: whether it is fresh, whether it tastes good, and whether it is safe (non-toxic and harmless);

[0089] Freshness means that the overall structure of the food cells is well preserved, without most of the cells disintegrating or decomposing;

[0090] Taste mainly refers to texture and taste. Taste can be enhanced by seasoning or additives, but the main determinant of taste is the food ingredients themselves.

[0091] Safety includes: no pesticide and veterinary drug residues, no mycotoxins, no excessive bacteria, no heavy metal accumulation, no excessive additives, etc.

[0092] The above is only a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can easily think of various changes or substitutions within the technical scope disclosed by the utility model, which should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. A multifunctional composite sensor device for food safety detection, characterized in that: It includes an open-end coaxial sensor, an electrochemical sensor / interdigital capacitance sensor and a temperature sensor which are composited inside a protective shell; in: The open-ended coaxial sensor is used to test the dielectric constant of a substance; The electrochemical sensor / interdigital capacitance sensor is used to test the electrochemical effect of a substance; The temperature sensor is used to detect the actual temperature and temperature change of the measured substance; The open-end coaxial sensor is a high-frequency electrode, the electrochemical sensor / interdigital capacitance sensor is a low-frequency electrode, and the temperature sensor includes a temperature sensing electrode; The low-frequency electrode is any one of an interdigitated capacitance electrode and a pin-type electrode; in: The electrode end of the interdigital capacitor electrode is provided with a switching device 1, which is used to replace the interdigital capacitor electrode at the electrode end; The electrode end of the pin-type electrode is provided with a second adapter device for replacing the stainless steel pin electrode.

2. A multifunctional composite sensor device for food safety detection according to claim 1, characterized in that: The number of the high-frequency electrodes is 1-3.

3. The multifunctional composite sensor device for food safety detection according to claim 1, characterized in that: The number of the low-frequency electrodes is 1-3.

4. The multifunctional composite sensor device for food safety detection according to claim 1, characterized in that: The probes of the high-frequency electrodes and the probes of the low-frequency electrodes are arranged in a cross-symmetric manner.

5. The multifunctional composite sensor device for food safety detection according to claim 2, characterized in that: The probe of the temperature sensing electrode is located in the middle of the high-frequency electrode probe and the low-frequency electrode probe.

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