RU2170928C1 - Method for carrying out remote spectral quality control of meat - Google Patents

Abstract

FIELD: medicine. SUBSTANCE: method involves exposing meat sample to monochromatic laser radiation having wavelength of 488 nm for analyzing resulting fluorescent luminescence in fluorescence band. The results are interpreted in terms of meat condition. Two spectral segments are selected in analyzing the fluorescent luminescence from fluorescence band by means of corresponding spectrum-selective interference filters. The segments have wavelength maximum of λ₁= 510 nm and λ₂=545 nm. Fluorescent luminescence intensities J₁ and J₂ are measured at the wavelength pointed out using corresponding photodetectors and J₁ and J₂ intensities are compared. J₁ / J₂ ratio being ≥ 1, the results of analysis are considered to be positive that means good quality of meat. The J₁ / J₂ ratio being <1, the results of analysis are considered to be positive that means the meat contains pathogenic bacteria. EFFECT: objective evaluation of meat quality. 2 dwg

Description

 The invention relates to the meat industry and may find application in operations of express quality control of meat and meat products.

 Quality control of meat and meat products, including express control, an important component of the technological process of meat processing, especially in line production. Ultimately, the quality of products issued to consumers, their cost, and the ability to timely select and apply adequate disinfection measures, including the application of measures to reduce microbiological contamination, depend on the efficiency of control and the objectivity of estimates.

Known methods for controlling the quality of meat and meat products based on physico-chemical analysis of the sample. For example, there is a method for determining the degree of freshness of meat described in [1], in which a sample of the test product is crushed, mixed with distilled water in a predetermined ratio, and the amount of the controlled agent, ammonia, released when the product lost freshness due to deamination proceeding under the action of enzymes of microorganisms. There is also a method of controlling the freshness of meat, described in [2], in which a sample of meat of a certain shape is kept for several days at a temperature of 4 ^o C, periodically controlling its elasticity compared to a sample of obviously fresh meat. Methods [1], [2] provide a high quality control, however, they require considerable time to obtain a result and are therefore unsuitable for express analysis.

 A known method [3] for controlling the quality of frozen products, for example fish, in which the quality of the product is established by the quantitative evaluation criterion for the level of muscle tissue destruction, which is determined by microscopy of the prepared sample by observing ultrastructural changes, including changes in the structure of myofibrillar proteins. Method [3] allows one to judge the time of the onset of critical periods of muscle tissue destruction as a result of activation of autocatalytic processes and evaluate the quality of the product subjected to any refrigeration treatment regardless of the period of refrigerated storage. Method [3] requires less time than methods [1], [2], however, it is also not suitable for rapid analysis.

 Among the methods of meat quality control, for example, the method [4] is known, in which a controlled sample is exposed to electric current of industrial frequency, and then the pH value is measured, according to the level of which meat is sorted into quality groups. With this method, the nutritional value of meat is mainly controlled, and such an important factor as the presence or absence of pathogenic bacteria on its surface is not established. In the method [4], the measurement of pH requires a certain amount of time, as a result of which this method is also not express.

 Among the methods for controlling the quality of meat, for example, a method [5] is known, which allows controlling meat, for example, fish meat, for the presence of extraneous dielectric inclusions, namely, for inclusion of parasites. In the method [5], a current is passed through the test sample and the disturbances or current deviations caused by the presence of parasites are recorded. This method has limited application, arising from the characteristics of the problem being solved, in particular, it does not allow one to judge the presence or absence of pathogenic bacteria on the meat surface. This method is not express.

 A similar problem to detect extraneous dielectric inclusions is solved in the method [6], in which a controlled meat sample is irradiated with electromagnetic waves in the range of 800 - 1800 nm, after which the absorption of electromagnetic waves is analyzed, comparing it with a predetermined, characteristic absorption of Anisakis and Phocanema nematodes. This method, as well as the method [5], has limited application, arising from the features of the problem being solved, and is not express.

 A known method [7] of meat quality control, based on exposure to electromagnetic radiation of a certain range of wavelengths and measuring the intensity of their reflection. Moreover, as an indicator correlating with meat quality, the ratio of the values of reflection intensity values of the test sample and the standard measured using a color comparator is used, and meat quality control is carried out taking into account the obtained values of the values of this ratio. The method allows for the rapid analysis of the quality of meat by its color and sorting of carcasses after slaughter of animals. However, the implementation of the method requires a knowingly benign reference sample, the color of which is close to the test and which must be changed when changing the batch of meat, which limits the possibilities of using the method.

 Known is the method described in [8] for monitoring the state of food products, in which diacetyl resulting from spoilage, such as chilled meat, is detected using aromatic orthodiamine with an acidic pH value, with subsequent registration of changes in the absorption or reflection of electromagnetic radiation characteristic of orthodiamine . The method [8] is quite effective, but not express.

 There is a method [9] for assessing the quality of meat of farm animals in the technological process of processing raw meat without preliminary sampling, based on measuring the magnitude of the intensity of reflected light with subsequent determination of the reflection coefficient. In this method, measuring the intensity of reflected light is carried out directly in the thickness of the test sample at a depth of 5-7 cm by introducing an optical needle into it, while the measurement uses a light flux with a wavelength of 600 - 720 nm. Measurements are made directly on the carcasses of cattle after slaughter and cooling on the long dorsi muscle. The method allows for the rapid analysis of the quality of meat by its reflectivity and sorting of carcasses after slaughter of animals. However, the possibilities of the method [9] are limited by the initial stage of processing raw meat, in particular, the method [9] is not applicable to frozen meat and does not allow to assess the presence or absence of pathogenic bacteria on the surface of the meat.

 Similarly to the method [9] in the method [10], the quality of the meat is also evaluated by its light reflecting ability in the thickness of the test sample by introducing into the latter using an optical probe made in the form of a lancet using a punch gun. Method [10] allows you to implement a rapid analysis of the quality of meat, including the percentage of veins in the carcass. The method [10] does not allow to assess the presence or absence of pathogenic bacteria on the surface of the meat, and is also not applicable to frozen meat.

 To assess the presence or absence of pathogenic bacteria on the surface of the meat, it is promising to use methods based on the phenomenon of photoluminescence - luminescence excited by optical radiation generated by the corresponding emitter. The ability to assess product quality by photoluminescence is due to the fact that under the influence of light, most substances and biological objects emit characteristic radiation for them, which forms an individual "portrait" of the product under study and the distortion of which indicates pathology.

 Among the methods for determining the quality of products based on the use of the phenomenon of photoluminescence, there is, for example, a method [11], in which the degree of damage of grain by microscopic fungi is estimated from the intensity of photoluminescence recorded in the wavelength range of 520 - 700 nm, while the photoluminescence of grain samples is initiated by their irradiation in the wavelength range of 360 - 500 nm. The degree of grain damage by microscopic fungi is estimated by comparing the photoluminescence intensity of the studied grain samples with the photoluminescence intensity of the control sample - ground grain without mushrooms. The need for a control sample is the disadvantage of the method that prevents its use as an express one.

A known method for assessing the quality of agricultural products [12], in particular carrot root crops, in which the detection of substandard root crops is carried out by measuring and analyzing their fluorescence spectra. In the method [12], fluorescence is initiated by irradiating root crops in two wavelength ranges of 290 ± 10 nm and 365 ± 10 nm. In this case, when irradiated in the wavelength range of 290 ± 10 nm, the fluorescence intensity J ₁ and J _{2 are} recorded in the wavelength regions of 337 ± 10 and 465 ± 10 nm, respectively. When irradiated in the wavelength range of 365 ± 10 nm, the fluorescence intensity of J ₃ and J _{4 is} recorded in the wavelength regions of 540 ± 10 and 575 ± 10 nm. When sorting root crops, it is considered that for conditioned root crops the ratio J ₁ / J ₂ ≅ 1.1, and for substandard ones - J ₁ / J ₂ > 1.1. When dividing sub-standard root crops, it is believed that in sick root crops (damaged by a pathogen) the value of J ₃ / J ₄ > 1.0, and in mechanically damaged ones - J ₃ / J ₄ ≅ 1.0. This method is effective and express, however, it can be used in the quality control of only a certain type of agricultural products - root crops, mainly carrot root crops.

 As a prototype of the proposed method - a method for remote spectral monitoring of meat quality - the method described in [13] was adopted, according to which the quality of meat is judged by the results of analysis of fluorescence radiation that occurs on the surface of meat infected with pathogenic bacteria when it is irradiated with monochromatic laser radiation of a certain wavelengths. The method adopted as a prototype is that a controlled meat sample is irradiated with monochromatic laser radiation with a wavelength of 488 nm, the integrated fluorescence intensity in the fluorescence spectrum band is estimated and meat quality is judged from it: more fluorescence radiation intensity - more pathogenic bacteria worse quality meat.

 The method adopted as a prototype provides a solution to the problem of express non-contact remote control of meat quality in general - suggests using monochromatic laser radiation of a certain wavelength to excite fluorescence on the surface of the meat, followed by analysis of this fluorescence radiation to establish the presence of pathogenic bacteria. However, in the prototype method there are no clearly defined quantitative criteria, which in practice makes the estimates made very subjective and uncertain, which impedes the real industrial use of this method.

 The task to be solved by the claimed invention is aimed at providing the possibility of obtaining, during express control of meat quality, a uniquely defined answer about the results of the analysis of the yes – no answer type based on the proposed quantitative criterion for assessing the fluorescence spectrum of the meat under study.

 The solution of this problem opens the way for industrial use of the proposed method as an effective remote non-contact express method for controlling the quality of meat and meat products.

The essence of the invention lies in the fact that in the method of remote spectral control of meat quality, comprising irradiating a controlled meat sample with monochromatic laser radiation with a wavelength of 488 nm and subsequent analysis of the resulting fluorescence radiation in the fluorescence band, according to which the state of the meat is judged in the analysis of fluorescence radiation two spectral regions with maxima per dl are extracted from the fluorescence band using appropriate spectrally selective interference filters the wavelengths λ ₁ = 510 nm and λ ₂ = 545 nm, measure the intensities J ₁ and J _{2 of the} fluorescence radiation at the indicated wavelengths with the corresponding photodetectors, compare the intensities J ₁ , J ₂ and with the value of the ratio J ₁ / J ₂ ≥ 1 give a positive assessment of the analysis, corresponding to high-quality meat, and when the value of the ratio J ₁ / J ₂ <1 give a negative assessment of the analysis, corresponding to meat with pathogenic bacteria.

 The essence of the claimed invention and the possibility of its implementation are illustrated in FIG. 1 and 2, where in FIG. 1 presents a structural diagram of a device that implements the inventive method; in FIG. 2 is a schematic diagram of the fluorescence emission spectrum of benign meat (curve I) and meat infected with pathogenic bacteria (curve II).

 A device that implements the inventive method contains (Fig. 1) a source of monochromatic radiation 1, an executive unit 2, blocks 3 and 4 of fluorescence receivers, as well as an analysis unit 5. The output of the radiation source 1 and the inputs of blocks 3 and 4 are connected to the executive unit 2 by the corresponding optical fibers 6. The outputs of blocks 3 and 4 are connected by the corresponding electric circuits to the inputs of the block 5.

 The source of monochromatic radiation 1 is a pulsed argon laser with a wavelength of 488 nm.

 The Executive unit 2 non-contact (remotely) interacts with a controlled sample of meat 7, directing radiation from source 1 to it and receiving the resulting fluorescence response.

 The Executive unit 2 contains a light channel, made in the form of a piece of fiber optic cable, structurally placed in the barrel of the "optical gun". This "optical gun" is equipped with a trigger (trigger), which is connected by a corresponding communication channel to the control input of the monochromatic radiation source 1 (in Fig. 1 this connection is shown by a dotted line).

Blocks 3 and 4 contain spectrally selective interference filters that separate two spectral regions with wavelengths λ ₁ = 510 nm and λ ₂ = 545 nm with a half width of 10 nm from the fluorescence band, as well as the corresponding photodetectors that convert the energy of optical radiation into energy of electrical signals corresponding to the intensities J ₁ and J _{2 of} fluorescence radiation at the indicated wavelengths.

The analysis unit 5 in the simplest case is a comparator forming the first output signal in the case when J ₁ ≥ J ₂ , i.e. when J ₁ / J ₂ ≥ 1, and the second output signal in the case when J ₁ <J ₂ , i.e. when J ₁ / J ₂ <1. The first output signal corresponds to a positive assessment of the analysis performed - in the absence of pathogenic bacteria on the controlled surface. The second output signal corresponds to a negative assessment of the analysis performed - if pathogenic bacteria are detected on a controlled surface.

In embodiments, block 5 can be implemented as an amplifier that implements the function of dividing two electrical quantities X / Y, corresponding to the indicated intensities J ₁ and J _{2 of} fluorescence radiation, and generates the first output signal of a positive evaluation of the analysis performed at J ₁ / J ₂ ≥ 1 and the second output signal of a negative evaluation of the analysis performed at J ₁ / J ₂ <1.

 The inventive method is as follows.

 The output of the light channel of the actuating element 2, i.e. the exit hole of the barrel of the "optical pistol", brought to the surface of the controlled sample 7 and pull the trigger. In this case, the control circuit of the monochromatic radiation source 1, a pulsed argon laser with a wavelength of 488 nm, is initiated. The laser generates a light pulse, which through the corresponding optical fiber 6 enters the light channel of the "optical gun", and from it to the surface of the test sample 7.

 The indicated laser radiation pulse initiates the fluorescence emission of the controlled sample. Moreover, as was revealed as a result of studies, the fluorescence emission spectrum has a different character for benign meat samples on the surface of which there are no pathogenic bacteria (Fig. 2, curve I), and for meat samples whose surface is infected (seeded) with pathogenic bacteria ( Fig. 2, curve II). Moreover, these spectra differ both in their intensity (the intensity of the fluorescent radiation of the meat infected with pathogenic bacteria is more than an order of magnitude higher than the intensity of the fluorescent radiation of benign meat) and in the form of frequency characteristics. So, in the case of benign meat, the fluorescence intensity in the spectral range 510-650 nm decreases, although not monotonously (Fig. 2, curve I), but in the case of infection by pathogenic bacteria, the fluorescence intensity first increases, reaching a maximum at the wavelength section of 540 -545 nm, and then begins to fall (Fig. 2, curve II). The indicated nature of curves I and II of FIG. 2 is stored for both fresh meat samples and meat samples stored in refrigerators and freezers. The revealed nature of curves I and II of FIG. 2 also holds for meat samples of various lots.

 The revealed difference in the fluorescence emission spectra of benign meat and meat, the surface of which is seeded with pathogenic bacteria, allows optical contactless express quality control of meat in accordance with the proposed method.

Moreover, in the process of analyzing the fluorescence radiation resulting from the irradiation of a controlled meat sample with monochromatic laser radiation with a wavelength of 488 nm, two spectral regions with maxima are isolated from the fluorescence band using the corresponding spectrally selective interference filters included in blocks 3 and 4 at wavelengths of λ ₁ = 510 nm and λ ₂ = 545 nm and measuring intensity of J ₁ and J ₂ fluorescence at these wavelengths corresponding photodetectors, are members of the units 3 4. In this case, the transformation of the optical signals having wavelengths λ ₁ = 510 nm and λ ₂ = 545 nm into electric signals corresponding to the intensities of J ₁ and J ₂ fluorescence at these wavelengths.

The thus measured intensities J ₁ and J _{2 of the} fluorescent radiation of the test meat sample at the indicated wavelengths are compared with each other in the analysis unit 5, for example, using a comparator. In this case, block 5, as described above, is made in such a way that in the case of benign meat (Fig. 2, curve I), i.e. when J ₁ ≥ J ₂ (J ₁ / J ₂ ≥ 1), the first output signal is generated at its output, indicating a positive assessment of the analysis. As such a signal, for example, a “logical 0” signal can be used. In the case of meat with pathogenic bacteria (Fig. 2, curve II), i.e. when J ₁ <J ₂ (J ₁ / J ₂ ≥ 1), a second output signal is generated at the output of block 5, indicating a negative assessment of the analysis performed. As such a signal can be used, for example, the signal "logical 1".

 The output signals of block 5 are used when deciding on the benign or poor quality of the controlled meat sample.

 At the same time, in the simplest case, a decision on the quality of meat can be made according to the results of express control at one point on the surface of the meat. As such a point, for example, a point in the anal area of a meat carcass can be selected.

 The results of express control can be used at many points, selected according to a specific pattern. The choice of control points, algorithms for processing control results at many points, the use of express analysis results to automate the process of meat sorting are not considered in this application.

 Thus, it can be seen from the foregoing that the claimed invention is technically feasible, industrially feasible and solves the stated technical problem of ensuring the possibility of obtaining a quick and unambiguously determined answer about the results of the analysis of the yes-no answer based on the proposed quantitative criterion during express quality control of meat Evaluation of the fluorescence spectrum of the test meat sample.

 These positive features of the proposed method provide broad prospects for its industrial use as an effective remote non-contact express method for monitoring the quality of meat and meat products by the presence or absence of pathogenic bacteria detected by the analysis of the fluorescence spectrum.

Sources of information
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Claims (1)

Method for remote spectral monitoring of meat quality, including irradiating a controlled meat sample with monochromatic laser radiation with a wavelength of 488 nm and subsequent analysis of the resulting fluorescence radiation in the fluorescence band, according to which the state of the meat is judged, which is distinguished from the fluorescence band in the analysis of fluorescence radiation using appropriate spectrally selective interference filter spectral portion with two maxima at wavelengths λ ₁ = 510 nm and ₂ = 545 nm, measured intensity of J ₁ and J ₂ fluorescence at these wavelengths respective photodetectors are compared between the values of the intensities of J _1, J ₂ and a value of the ratio J ₁ / J ₂ ≥ 1 gives a positive evaluation produced the analysis corresponding quality meat, and when the value of the ratio J ₁ / J ₂ <1 give a negative assessment of the analysis, corresponding to meat with pathogenic bacteria.

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