Patent Application
20230417645
This patent application claims the benefit and priority of Chinese Patent Application No. 202210739102.X, filed with the China National Intellectual Property Administration on Jun. 28, 2022, the disclosure of which is incorporated by reference herein in its entirety as part of the present application.
The present disclosure relates to the technical field of bacterial testing, and in particular relates to a device and method for rapid determination of total bacterial count based on multi-wavelength reflectance spectrum.
BACKGROUND
Total bacterial count refers to the total number of bacterial colonies produced in a gram (milliliter) of sample, which is obtained by culturing the sample on a common nutrient agar plate at 37° C. for 48 h under aerobic conditions and converting the count of the produced colonies. The total bacterial count is an important parameter index to determine the quality of a plurality of to-be-tested samples. When coming into contact with food and other samples with total bacterial count exceeding the standard, the human is easy to suffer from various diseases, endangering health and even life safety.
With the substantial improvement of living standards, people's requirements for food quality are getting higher and higher, and safe and high-quality food is increasingly favored by consumers. China's food industry, as a sunrise industry, has seen a rapid increase in its total output value in recent years, and there is an urgent need for rapid and efficient quality control means and testing equipment. The total bacterial count is an important biological index for food, the testing of its content is always throughout the whole production process of milk, meat and eggs, which is an important reference for evaluating the quality of food and is also a hygienic index mandatorily required by the state. Rapid and correct evaluation of the effectiveness of cleaning and disinfection of repeatedly used medical devices is an important factor for effective control of cross infection in hospital, and the occurrence of cross-contamination in hospital can be effectively controlled by sampling, culturing, monitoring, and rapidly detecting the bacteria. In addition, the daily chemical products are also very vulnerable to microbial contamination, especially the excessive total bacterial count may seriously damage the quality and economic benefits of the daily chemical products.
In the field of military affairs and national defense, due to the long-term service lurking below the water surface, the ventilation conditions of nuclear submarines are poor, leading to extremely serious bacterial pollution in submarine cabins. In addition, in space, living bacteria have been found outside the International Space Station. Long-distance space travel and long-term residence may be threatened by bacteria. Bacterial communities have a certain probability of mutating into deadly species in space radiation environment, and may even mutate when exposed to microgravity and space radiation environments. At present, the national defense security has been extended to “biological territory”. For example, the United States has issued three biological safety plans, such as Biosurveillance plan, and has conducted a series of research over the three plans, which plays an important role in rapid sample testing, biological anti-terrorism and food-borne disease prevention. Germany, Britain, Australia and other countries have also developed corresponding biological rapid testing plans, so biosafety plays an important role.
The national mandatory requirements for the total bacterial count include food, drinking water, daily chemicals and the like. Moreover, in the closed environment such as nuclear submarines and astronauts' living capsules, the problem of excessive total bacterial count is easy to be caused. Therefore, it is of a great significance for developing an instrument for rapid testing of total bacterial count with high testing speed, high accuracy and wide applicability to supervise the variation law of the total bacterial count of food, solid samples and drinking water, and to protect the health of soldiers and residents.
To achieve the determination of the total bacterial count of a sample, the researchers have developed a plurality of testing methods. Nowadays, the testing methods for total bacterial count are mainly divided into two types: one is the traditional standard plate count method, and the other is a series of new rapid testing methods, such as flow cytometry, electrical impedance analysis, ELISA (enzyme-linked immunosorbent assay), ATP (Adenosine triphosphate) bioluminescence, and turbidimetry. Although there are many methods for rapid testing of total bacterial count, so far, none of them can satisfy the requirements of accurate testing results, low operating cost and simple operation, and all of them have certain defects and applicable scope.
To overcome the defects in the prior art, the present disclosure provides a device and method for rapid determination of total bacterial count based on multi-wavelength reflectance spectrum. The technical problem that the existing testing method has a large error in the testing result due to the differences in the size of individual bacteria, and the state and color of the sample is solved, thus achieving the purpose of rapidly and accurately determining the total bacterial count.
To solve the problems above, the technical solution employed by the present disclosure is as follows:
A device for rapid determination of total bacterial count based on multi-wavelength reflectance spectrum comprises:
As a preferred embodiment of the present disclosure, the photoelectric conversion element comprises:
As a preferred embodiment of the present disclosure, the monochromator is an optical filter or an optical grating.
As a preferred embodiment of the present disclosure, the light-emitting element is a halogen lamp.
As a preferred embodiment of the present disclosure, the thermostatic element is a semiconductor temperature controller.
A method for rapid determination of total bacterial count based on multi-wavelength reflectance spectrum comprises the following steps:
As a preferred embodiment of the present disclosure, the heating treatment condition is as follows: heating at 45° C. to 47° C. for 3 min to 5 min, and the heating culture condition is as follows: heating at 45° C. to 47° C. for 15 min to 17 min; and the total time for heating treatment and heating culture is 20 min.
As a preferred embodiment of the present disclosure, during preparation of the standard sample, the method comprises the following steps:
As a preferred embodiment of the present disclosure, the acquisition process of the standard curve is as follows:
As a preferred embodiment of the present disclosure, the acquisition process of the true value of the total bacterial count is as follows: the total bacterial count of the standard sample subject to heating culture that is tested according to the testing of the Chinese standard GB4789.2-2016 is the true value of the total bacterial count.
Compared with the prior art, the present disclosure has the beneficial effects that:
The present disclosure is further described in detail below with reference to the accompanying drawings and specific embodiments.
In the drawings: 1—light-emitting element; 2—monochromator; 3—integrating sphere; 4—thermostatic element; 5—optical fiber; 6—photomultiplier; 7—oscilloscope.
A device for rapid determination of total bacterial count based on multi-wavelength reflectance spectrum provided by the present disclosure, as shown in
The integrating sphere 3 comprises a hollow inner surface and is a spherical cavity with extremely high diffuse reflectivity, and its inner surface may be considered as a Lambert emitter, it is a photometric measuring instrument, commonly used in laser power and energy, material reflectivity measurement, etc. When a beam of laser enters the integrating sphere, a uniform and isotropic diffuse-reflection optical field may be formed in the integrating sphere. The use of integrating sphere 3 may reduce and remove the measurement error caused by differences in light shape, divergence angle and responsiveness at different locations on the measurement device.
The thermostatic element 4 is designed for the condition that most of actual biological samples present different sample states such as emulsions or suspensions. After the monochromatic light passes through the standard sample inside the thermostatic element 4, diffuse reflection occurs in the integrating sphere 3, and the absorption of the diffuse reflectance spectroscopy of the standard sample is determined. Therefore, the problem of absorbance error caused by direct transmittance determination is effectively overcome by using a relationship that the reflected light intensity is directly proportional to the total bacterial count.
The testing process of the present disclosure is as follows:
In the subsequent testing, the reflected light intensity values of the liquid sample at 5 min and 20 min are determined according to the above steps, and the oscilloscope 7 is configured to convert the reflected light intensity value into the value of total bacterial count of the sample by using the standard curve and display the value of total bacterial count.
Further, the determination device is further provided with a “view” button, and the testing result of the sample may be displayed by pressing the “view” button.
Further, the determination device is further provided with a “print” button, and this measurement result may be printed by pressing the “print” button.
Further, the determination device may be used together with software sscom 3.2, the data is recorded and converted into TXT text files by the software, so the determined data can be conveniently analyzed, compared and tracked later, and then is stored in a flash memory medium.
Further, the photoelectric conversion element comprises an optical fiber 5 and a photomultiplier 6. The optical fiber 5 is connected to the integrating sphere 3 and configured to receive the monochromatic light converged by the integrating sphere 3, and the photomultiplier 6 is connected to the optical fiber 5 and configured to convert an optical signal conducted by the optical fiber 5 into an electric signal.
The photomultiplier 6 is a photoelectric induction element based on external photoelectric effect, secondary electron emission and electron optics theory, which is generally used in the ultraviolet, visible and near-infrared regions of the spectrum in practice. In addition to a photocathode and an anode, the internal structure of the photomultiplier 6 has a plurality of tile-shaped dynodes placed between two poles thereof. In use, voltage accelerating electrons may be generated between two adjacent dynodes in the tube. The photocathode of the photomultiplier 6 may release photoelectrons after being irradiated by a light source, and then the photoelectrons may irradiate on first dynodes under the action of an electric field to form the secondary emission and the tertiary emission of electrons, finally causing continuous multiplication of the number of electrons in the tube. Finally, the electrons collected by the anode of the photomultiplier 6 may be increased by 104 to 108 times, and weak optical signals in the system can be detected.
Further, the monochromator 2 is an optical filter or an optical grating. The optical filter is a Fabry-Perot optical filter, which uses liquid crystal as the cavity material, and has the advantages of narrow bandwidth, low energy consumption, wide tuning range, low driving voltage, simple structure, etc.
A large number of parallel notches with equal width and equal spacing are engraved on a transparent glass sheet to form the optical grating, where the notches are opaque parts. Generally, there are dozens or even thousands of slits per millimeter in the optical grating. When light waves are transmitted or reflected on the optical grating, diffraction may occur to form a certain diffraction pattern. Due to the fact that the light with different wavelengths has different diffraction angles, the light with different wavelengths in the incident light can be separated by the optical grating.
Further, the light-emitting element 1 is a halogen lamp. The principle of the halogen lamp is that the halogen gas such as iodine or bromine is injected into the bulb, the sublimated tungsten wire reacts with halogen at a high temperature, and the cooled tungsten will re-solidify on the tungsten wire to form a balanced cycle to prevent the tungsten wire from premature fracture, and therefore the halogen lamp has a longer life than an incandescent lamp.
Further, the thermostatic element 4 is a semiconductor temperature controller. The semiconductor temperature controller has the following advantages: (1) it has a simple structure, no refrigerant, no wear, long life, high working reliability, and low requirements for working environment; (2) heating temperature and speed may be controlled by the working current, and the control is flexible and the start is fast; (3) the volume is small, the weight is light, and the maintenance is convenient; (4) the control precision is high; and (5) the temperature control range is wide. Therefore, the accuracy of the determination result may be further ensured by using the semiconductor temperature controller.
A method for rapid determination of total bacterial count based on multi-wavelength reflectance spectrum provided by the present disclosure, as shown in
In the step S2, the heating treatment condition is as follows: heating at 45° C. to 47° C. for 3 min to 5 min, and the heating culture condition is as follows: heating at 45° C. to 47° C. for 15 min to 17 min; and the total time for heating treatment and heating culture is 20 min.
Further, after being heated at 47° C. for 5 min, the standard sample is used as a blank, its reflected light intensity value is determined, and after being continuously cultured at 47° C. for 15 min, its reflected light intensity value is determined again. As the variation of the reflected light intensity of the mixed liquid is caused by bacterial reproduction, the interference of the sample color on the determination result may be eliminated by using the difference between two reflected light intensity values. Meanwhile, as the bacteria are reproduced in a binary fission manner, the total bacterial count of the standard sample after 20 min is increased twice as much as the original, and the value of total bacterial count of the original sample may be obtained from the value of total bacterial count of the standard sample.
In the above step S2, different wavelengths of the monochromatic light are 440 nm, 520 nm, 600 nm and 640 nm, respectively. The monochromatic light with different wavelengths is configured to determine the absorbance of the sample at different wavelengths, and then an average value of the absorbance is calculated; the maximum absorption wavelength of the giant bacteria is at 440 nm, the maximum absorption wavelength of the large bacteria is at 520 nm, the maximum absorbance wavelength of the small bacteria is at 640 nm, and the maximum absorbance wavelength of the medium-sized bacteria is at 580 to 600 nm. The monochromatic light with the four wavelengths can embrace the bacteria with different individual sizes, thus overcoming the technical problem of different maximum absorption wavelengths caused by the difference of individual sizes of different species of bacteria.
Further, during preparation of the standard sample, the method comprises:
The steps are specifically as follows:
Further, the acquisition process of the standard curve is as follows:
Further, the acquisition process of the true value of the total bacterial count is as follows: according to the testing of the Chinese standard GB4789.2-2016 Food microbiological examination: Aerobic plate count, the total bacterial count of the standard sample after heating culture is the true value of the total bacterial count. The standard specifies the determination method for aerobic plate count of food.
The present disclosure is further described below with specific embodiments
Testing of Emulsion Samples (Raw Milk, Milk Beverage, etc.)
A true value of total bacterial count of a dairy product is tested by using a standard plate count (GB4789.2-2016). 1.0 mL of dairy product is added into 1.0 mL of sterilized skim milk, an absorbance value determined by an instrument is used as a reference value, an initial absorbance value of the to-be-tested emulsion sample is set to be 0; by taking a BaSO4 standard white material as a reflectance reference, an initial reflected light intensity value of the instrument is set to be 100%, after being heated at 47° C. for 5 min, the mixed liquid is used as a blank, and its reflected light intensity value is determined; after being continuously cultured at 47° C. for 15 min, its reflected light intensity value is determined again; and after being cultured for 20 min, its reflected light intensity value increases due to the production of the bacteria. The reflected light intensity value of the tested dairy product is recorded by the instrument at the moment; and after mass sampling and testing, the reflected light intensity value of the dairy product that has been cultured for 20 min is fitted as a curve equation with the true value of the total bacterial count to establish a standard curve.
Reflected light intensity values of 15 groups of emulsion samples (including raw milk, milk beverage, etc.) are determined according to above steps, and then the reflected light intensity values thereof are converted into the values of total bacterial count of the samples by using the standard curve.
Testing of Water Samples:
10 mL of water sample is subjected to sterile filtration by using a filtering membrane having a pore size of 10 μm to remove solid particles in the water so as to exclude interference thereof on the test. 1.0 mL of water sample after sterile filtration is added into 1.0 mL of sterilized skim milk, an absorbance value determined by an instrument is used as a reference value, an initial absorbance value of the to-be-tested water sample is set to be 0; by taking a BaSO4 standard white material as a reflectance reference, an initial reflected light intensity value of the instrument is set to be 100%, after being heated at 47° C. for 5 min, the mixed liquid is used as a blank, and its reflected light intensity value is determined; after being continuously cultured at 47° C. for 15 min, its reflected light intensity value is determined again; and after being cultured for 20 min, its reflected light intensity value increases due to the production of the bacteria. The reflected light intensity value of the tested water sample is recorded by the instrument at the moment; and after mass sampling and testing, the reflected light intensity value of the water sample that has been cultured for 20 min is fitted as a curve equation with the true value of the total bacterial count to establish a standard curve.
Reflected light intensity values of 15 groups of water samples (including barreled water, water of rivers and lakes, etc.) are determined according to above steps, and then the reflected light intensity values thereof are converted into the values of total bacterial count of the samples by using the standard curve.
Testing of Solid Samples:
25.00 g of solid sample (bread, candies, preserved fruit, sausage, etc.) is placed into a sterile homogenizing cup filled with 225.00 mL of normal saline, and is homogenized at 8,000 r/min to 10,000 r/min for 1 min to 2 min; or the 25.00 g of solid sample is placed into a sterile homogenizing bag filled with 225 mL of diluent, and then is flapped by a flapping homogenizer for 1 min to 2 min so as to obtain a sample homogenate with a solid sample weight ratio of 10% for later use.
1.0 mL of sample homogenate is added into 1.0 mL of sterilized skim milk, an absorbance value determined by an instrument is used as a reference value, an initial absorbance value of the to-be-tested solid sample is set to be 0; by taking a BaSO4 standard white material as a reflectance reference, an initial reflected light intensity value of the instrument is set to be 100%, after being heated at 47° C. for 5 min, the mixed liquid is used as a blank, and its reflected light intensity value is determined; after being continuously cultured at 47° C. for 15 min, its reflected light intensity value is determined again; and after being cultured for 20 min, its reflected light intensity value increases due to the production of the bacteria. The reflected light intensity value of the tested solid sample is recorded by the instrument at the moment; and after mass sampling and testing, the reflected light intensity value of the solid sample that has been cultured for 20 min is fitted as a curve equation with the true value of the total bacterial count to establish a standard curve.
Reflected light intensity values of 15 groups of solid samples (including candies, sausages, etc.) are respectively determined according to above steps, and then the reflected light intensity values are converted into the values of total bacterial count of the samples by using the standard curve.
Testing of Semi-Solid Samples:
15.00 g of semi-solid sample (vegetable puree, fruit puree, etc.) is placed into a conical flask filled with 85.00 mL of normal saline, and then is uniformly mixed with the normal saline by a vortex mixer to obtain a sample homogenate with a semi-solid sample weight ratio of 15% for later use.
1.0 mL of sample solution after pretreatment of the semi-solid sample is added into 1.0 mL of sterilized skim milk, an absorbance value determined by an instrument is used as a reference value, an initial absorbance value of the to-be-tested semi-solid sample is set to be 0; by taking a BaSO4 standard white material as a reflectance reference, an initial reflected light intensity value of the instrument is set to be 100%, after being heated at 47° C. for 5 min, the mixed liquid is used as a blank, and its reflected light intensity value is determined; after being continuously cultured at 47° C. for 15 min, its reflected light intensity value is determined again; and after being cultured for 20 min, its reflected light intensity value increases due to the production of the bacteria. The reflected light intensity value of the tested semi-solid sample is recorded by the instrument at the moment; and after mass sampling and testing, the reflected light intensity value of the semi-solid sample that has been cultured for 20 min is fitted as a curve equation with the true value of the total bacterial count to establish a standard curve.
Reflected light intensity values of 15 groups of semi-solid samples (including rice, flour, etc.) are respectively determined according to above steps, and then the reflected light intensity values are converted into the values of total bacterial count of the samples by using the standard curve.
Testing of Semi-Fluid Samples:
10.00 g of semi-fluid sample (daily chemical product, mixed congee, etc.) is placed into a conical flask filled with 90.00 mL of normal saline, and then is uniformly mixed with the normal saline by a vortex mixer to obtain a sample homogenate with a semi-fluid sample weight ratio of 10% for later use.
1.0 mL of sample homogenate is added into 1.0 mL of sterilized skim milk, an absorbance value determined by an instrument is used as a reference value, an initial absorbance value of the to-be-tested semi-fluid sample is set to be 0; by taking a BaSO4 standard white material as a reflectance reference, an initial reflected light intensity value of the instrument is set to be 100%, after being heated at 47° C. for 5 min, the mixed liquid is used as a blank, and its reflected light intensity value is determined; after being continuously cultured at 47° C. for 15 min, its reflected light intensity value is determined again; and after being cultured for 20 min, its reflected light intensity value increases due to the production of the bacteria. The reflected light intensity value of the tested semi-fluid sample is recorded by the instrument at the moment; and after mass sampling and testing, the reflected light intensity value of the semi-fluid sample that has been cultured for 20 min is fitted as a curve equation with the true value of the total bacterial count to establish a standard curve.
Reflected light intensity values of 15 groups of semi-fluid samples (including rice, flour, etc.) are respectively determined according to above steps, and then the reflected light intensity values are converted into the values of total bacterial count of the samples by using the standard curve.
Testing of Gel-Like Samples:
20.00 g of gel-like samples (Doufu, etc.) is placed into a sterile homogenizing cup filled with 80.00 mL of normal saline, and then is homogenized at 8,000 r/min to 10,000 r/min for 1 min to 2 min to obtain a sample homogenate with a gel-like sample weight ratio of 20% for later use.
1.0 mL of sample solution after the pretreatment of the gel-like sample is added into 1.0 mL of sterilized skim milk, an absorbance value determined by an instrument is used as a reference value, an initial absorbance value of the to-be-tested gel-like sample is set to be 0; by taking a BaSO4 standard white material as a reflectance reference, an initial reflected light intensity value of the instrument is set to be 100%, after being heated at 47° C. for 5 min, the mixed liquid is used as a blank, and its reflected light intensity value is determined; after being continuously cultured at 47° C. for 15 min, its reflected light intensity value is determined again; and after being cultured for 20 min, its reflected light intensity value increases due to the production of the bacteria. The reflected light intensity value of the tested gel-like sample is recorded by the instrument at the moment; and after mass sampling and testing, the reflected light intensity value of the gel-like sample that has been cultured for 20 min is fitted as a curve equation with the true value of the total bacterial count to establish a standard curve.
Reflected light intensity values of 15 groups of gel-like samples (jellies, etc.) are respectively determined according to above steps, and then the reflected light intensity values are converted into the value of the total bacterial count of the sample by using the standard curve.
Testing of Fluid Samples:
10.00 g of fluid sample (juice, soybean milk, etc.) is placed into a conical flask filled with 190.00 mL of normal saline, and then is uniformly mixed with the normal saline by a vortex mixer to obtain a sample homogenate with a fluid sample weight ratio of 5% for later use.
1.0 mL of sample solution after the pretreatment of the fluid sample is added into 1.0 mL of sterilized skim milk, an absorbance value determined by the instrument is used as a reference value, an initial absorbance value of the to-be-tested fluid sample is set to be 0; by taking a BaSO4 standard white material as a reflectance reference, an initial reflected light intensity value of the instrument is set to be 100%, after being heated at 47° C. for 5 min, the mixed liquid is used as a blank, and its reflected light intensity value is determined; after being continuously cultured at 47° C. for 15 min, its reflected light intensity value is determined again; and after being cultured for 20 min, its reflected light intensity value increases due to the production of the bacteria. The reflected light intensity value of the tested fluid sample is recorded by the instrument at the moment; and after mass sampling and testing, the reflected light intensity value of the fluid sample that has been cultured for 20 min is fitted as a curve equation with the true value of the total bacterial count to establish a standard curve.
Reflected light intensity values of 15 groups of fluid samples (broth, etc.) are respectively determined according to above steps, and then the reflected light intensity values are converted into the value of the total bacterial count of the sample by using the standard curve.
Suspension Samples
20.00 g of suspension sample (blood, etc.) is placed into a conical flask filled with 800.00 mL of normal saline, and then is uniformly mixed with the normal saline by a vortex mixer to obtain a sample homogenate with a suspension sample weight ratio of 10% for later use; then the sample homogenate is centrifuged by a centrifuge at 7,000 rpm to 10,000 rpm for 15 min to obtain supernatant for later use.
1.0 mL of sample solution after the pretreatment of the suspension sample is added into 1.0 mL of sterilized skim milk, an absorbance value determined by the instrument is used as a reference value, an initial absorbance value of the to-be-tested suspension sample is set to be 0; by taking a BaSO4 standard white material as a reflectance reference, an initial reflected light intensity value of the instrument is set to be 100%, after being heated at 47° C. for 5 min, the mixed liquid is used as a blank, and its reflected light intensity value is determined; after being continuously cultured at 47° C. for 15 min, its reflected light intensity value is determined again; and after being cultured for 20 min, its reflected light intensity value increases due to the production of the bacteria. The reflected light intensity value of the tested suspension sample is recorded by the instrument at the moment; and after mass sampling and testing, the reflected light intensity value of the suspension sample that has been cultured for 20 min is fitted as a curve equation with the true value of the total bacterial count to establish a standard curve.
Reflected light intensity values of 15 groups of suspension samples (Barium sulfate suspension, etc.) are respectively determined according to above steps, and then the reflected light intensity values are converted into the value of the total bacterial count of the sample by using the standard curve.
The total bacterial count of 15 groups (Examples 1-15) of emulsion samples is determined by the device and method of the present disclosure (hereinafter referred to as instrumental method), and the accuracy is analyzed. The specific determination results and analysis results are shown in Table 1 and Table 2:
It can be known from Table 2 that, within the 95% confidence interval, a P value (Two-tailed value) obtained by paired T-test is 0.335, P>0.05, and P value greater than 0.05 (i.e., the difference between the samples is not significant) indicates that there is no significant difference between the results of the total bacterial count of the emulsion sample tested by the instrumental method and by the standard method (standard plate count), and the accuracy of the total bacterial count of the emulsion sample tested by the instrumental method is high.
The total bacterial count of 15 groups (Examples 16-30) of water samples is determined by the instrumental method (embodiments 16 to 30), and the accuracy is analyzed. The specific determination results and analysis results are shown in Table 3 and Table 4:
It can be known from Table 4 that, within the 95% confidence interval, the P value (two-tailed value) obtained by paired T-test is 0.721, P>0.05, and P value greater than 0.05 (i.e., the difference between samples is not significant) indicates that there is no significant difference between the results of the total bacterial count of the water sample tested by the instrumental method and by the standard method (standard plate count), and the accuracy of the total bacterial count of the water sample tested by the instrumental method is high.
Solid, semi-solid, semi-fluid, gel-like, fluid and suspension samples (embodiments 30 to 120) are compared and analyzed by T-test, and the P values are all greater than 0.05, indicating that there is no significant difference between the results of the total bacterial count of the above samples tested by the instrumental method and by the standard method, and the accuracy of the value of total bacterial count of the above samples tested by the instrumental method is high.
The standard curve established for the emulsion sample is as shown in
The standard curve established for the water sample is as shown in
It can be seen from the standard curves established for the solid, semi-solid, semi-fluid, gel-like, fluid and suspension samples that R2 is all greater than 99%, so the standard curves established for the solid, semi-solid, semi-fluid, gel-like, fluid and suspension samples are highly consistent with the determined data.
It can be known from above that the P values of comparative analysis results of T-test in all embodiments are all greater than 0.05, and correlation coefficient R2 values of the standard curves established for various samples are all greater than 99%, fully indicating that the total bacterial count of emulsion, water, solid, semi-solid, semi-fluid, gel-like, fluid and suspension samples can be accurately determined by using the device and method of the present disclosure, and the technical problem of large determination error in the prior art is overcome.
The above-mentioned embodiments are only the preferred embodiments of the present disclosure, and are not intended to limit the scope of the present disclosure. Any insubstantial changes and substitutions made by those skilled in the art on the basis of the present disclosure are within the scope of the present disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202210739102.X | Jun 2022 | CN | national |
