CN100487429C - Scatheless method for testing freshness of livestock and birds meat quickly and device thereof - Google Patents

Abstract

The invention provides a detecting method for testing freshness of livestock and bird meat and the equipment. The method uses three beams with known intension to incident into the meat, and tests the optical intensity of different wavelength ejected from the two ring areas of the meat surfaces, and uses the absorbing and the dispersion coefficients to represent the freshness degree. The equipment comprises the photoelectric detecting unit, the CPU and the displaying unit. The light source of the photoelectric detecting unit sends out orderly three beams with different lengths and the two photoelectric detectors are the two rings using the detector as the center with different central semidiameters. The invention has high precision and fast testing speed.

Description

The method and the device of the harmless fast detecting of a kind of livestock and poultry meat freshness

Technical field

The present invention relates to method and device that a kind of livestock and poultry meat freshness detects, particularly a kind of method and device that is used to detect the harmless fast detecting of livestock and poultry meat deep layer freshness.

Background technology

Along with improving constantly of people's living standard, the consumption of meat amount increases day by day, and people improve constantly especially for the quality hygienic requirements of meat, and freshness how to evaluate meat is accurately concerning people's vital interests.All there is explicit stipulation in China to the hygienic standard that aquatic foods freeze livestock and poultry meat, according to hygienic standard, and the method that mainly adopts the sense organ standard to combine to the evaluation of meat freshness with physical and chemical standards.Sense organ standard main reference be meat color and luster, viscosity, elasticity, smell etc.; Physical and chemical standards mainly is the mensuration to meat total volatile basic nitrogen etc.

The rotten corrupt decomposable process that mainly is meant meat protein under effects such as microbial protease and endopeptidase of meat.Thereby judge that at present the meat freshness mainly carries out from characteristic and content, number of bacteria and three aspects of pollution level of the sensory trait of meat, corrupt decomposition product, existing detection technique mainly contains following several: the test of (1) total volatile basic nitrogen (TBV-N): no matter adopt Kjeldahl, still adopt the spectrophotometric spectra method, all to do pre-treatment, measure again after the extraction meat extract meat.Its operation steps is loaded down with trivial details, and the test duration is long, and is not Non-Destructive Testing, is difficult to satisfy current detection requirement for the batch samples quick nondestructive.(2) by of the influence of test pH value representation: Application No. 20020027074 to freshness, patent name is represented the freshness of rice for what introduce in " pHsensor " with the pH value, but when the pH value is used for the freshness test of livestock and poultry meat, be vulnerable to kill factor affecting such as preceding situation, thereby be difficult to reflect the truth that the meat freshness changes with this index separately such as kind, sampling position, domestic animal.(3) K value mensuration: behind the animal dead, the adenosine triphosphate atp in its meat is decomposed into adenosine diphosphate (ADP) (ADP) → adenosine monophosphate (AMP) → inosinicacid (IMP) → inosine (HER), hypoxanthine (HE) successively under the effect of ATP enzyme.Inosinicacid (IMP) claims 5 again '-inosinic acid, be the intermediate product of ATP, and the final product that ATP decomposes is inosine, hypoxanthine at decomposable process.The ratio of the quality sum of inosine, hypoxanthic semi-invariant and above-mentioned decomposable process material is called the K value.As disclosed method among the Jap.P. JP59130200, obtain a certain amount of meat extract, separate ATP and analyte in the purification sample.Need do a large amount of pre-treatment work but this method is extracted sample, and test is extract in the meat, can not satisfies harmless, requirement fast and accurately.(4) differentiate freshness by smell: as disclosed method among the Jap.P. JP6011501, the meat sample is carried out pre-treatment, extract gravy, immerse with filter paper and wherein extract the gravy sample, the test smell obtains freshness.Need pre-treatments but the problem that this method exists is a sample, and the smell test can only work as when meat severe goes bad and just sensitivity preferably can be arranged; This kind method neither can't harm, method fast.(5) detect surperficial yellowish pink and reflect freshness: as disclosed method among the Jap.P. JP4350540, the illumination of using the certain wavelength of light emitted is to the object of reference surface, the light of returning by the receiver detection of reflected; Object of reference and light source, detecting device have certain distance; The illumination of the same wavelength of light emitted is to meat surface, and the light that the receiver detection of reflected is returned calculates the reflection absorbance, and adopts artificial neural network to set up and the corresponding mathematical model of yellowish pink standard this value, and it is yellowish pink to be used for prediction, and then infers freshness.Disclosed method among the Jap.P. JP2003121351 and for example adopts the test of multi-wavelength method to obtain the light of returning from surface reflection and the experimental formula of surperficial freshness.But above-mentioned two kinds of methods all can only reflect the state on surface, and because kind, the domestic animal of having adopted experimental formula, its result to be subjected to meat kills the influence of preceding situation, rough surface situation, are difficult to the accurate measurement of meat freshness.

In sum, used being used at present detects the method or the length consuming time of the freshness situation of fowl poultry kind raw meat, is unfavorable for fast detecting; Perhaps belong to intrusive mood and detect, can not finish Non-Destructive Testing; Perhaps can only detect the surperficial freshness of raw meat, can not detect the deep layer freshness situation of raw meat, representativeness is not strong; Perhaps used apparatus structure complexity is not suitable for on-the-spot fast detecting.Exist in detecting above-mentioned measurement length consuming time, operation to require high, expense more greatly and the predicament of can not deep layer measuring owing to utilize prior art to carry out physico-chemical method, thereby often rely on the reviewer to come color, matter to carry out analytical test in the check at the scene to meat according to the personal experience, inevitably contain very big subjective factor, this has influenced the correct evaluation to meat quality undoubtedly.Therefore just need set up a kind of new evaluation standard and a kind of harmless rapid detection apparatus of development, remedying the deficiency of current detection method, feasible easy to detect, accurate, objective to the meat freshness.

Summary of the invention

The objective of the invention is, at above-mentioned the deficiencies in the prior art, propose the method and apparatus of the harmless fast detecting of a kind of livestock and poultry meat freshness, this method can detect the deep layer freshness of livestock and poultry meat, clearly provides the freshness parameter, the precision height, and selectivity is strong; This apparatus structure is simple, is easy to carry.

In order to achieve the above object, the present invention realizes by following method step and technical scheme:

A kind of livestock and poultry meat freshness can't harm method for quick, comprises the steps:

1, the wavelength coverages with at least 3 bundle known strength are that the light of the different wave length of 730nm～1100nm is injected meat inside from the meat surface, comprise the light intensity that detects the different wave length that scatters out in the meat at least in two zoness of different of first area and second area on the meat surface.

2, calculate by following formula and respectively restraint the diffusion of light ratio

$R_k^x=\frac{I_k}{I_{\mathrm{kr}}^x}$

In the formula, k=1,2 ... n, the footnote of the light source of expression different wave length, n 〉=3; I _kIt is the light intensity of k bundle light incident;

The organization internal scattering that is k bundle light process object to be detected is afterwards in the detected diffusion light intensity of meat surf zone, x=1,2; 1 expression first area, 2 expression second areas; R is the sign of diffused light;

3, to the incident light of same wavelength, but detected diffusion rate value carries out data operation by following described formula on the zones of different:

$\&PartialD;R_{{\mathrm{\&lambda;}}_K}=\log \frac{I_k}{I_{\mathrm{kr}}^2}-\log \frac{I_k}{I_{\mathrm{<figure-callout\; id="1"\; label="kr"\; filenames="C200510059937E00132.png"\; state="\{\{state\}\}">kr</figure-callout>}}^1},$

${\mathrm{\&mu;}}_a^{{\mathrm{\&lambda;}}_k}{\mathrm{\&mu;}}_s^{{\mathrm{\&lambda;}}_k}=\frac{{(\ln 10\frac{\&PartialD;R_{{\mathrm{\&lambda;}}_k}}{\mathrm{\&Delta;\&rho;}}-\frac{2}{\mathrm{\&rho;}})}^2}{3}$

${\mathrm{fre}}_{\mathrm{index}}=\frac{1}{3}\underset{k=1}{\overset{3}{\mathrm{\&Sigma;}}}{\mathrm{\&mu;}}_a^{{\mathrm{\&lambda;}}_k}{\mathrm{\&mu;}}_s^{{\mathrm{\&lambda;}}_k}$

In the formula, λ k represents different wave length; Δ ρ is the centre distance in two zones; ρ is and the zone of incident beam apart from each other and the distance of incident beam; μ _aBe absorption coefficient, μ _sBe scattering coefficient, represent freshness with the product mean value of absorption coefficient and scattering coefficient, this index is fre _Index

4) according to fre _IndexValue divide three grades with the freshness of meat: fre _Index〉=0.075mm ^-2Expression one-level freshness, 0.075mm ^-2Fre _Index〉=0.055mm ^-2Represent secondary freshness, fre _Index＜0.055mm ^-2Expression is rotten.

In the said method, at least two zones are to be two annular regions that center radius is different at center with the incident beam described in the step 1), the center radius of the annulus of second annular region is 10mm～40mm, the center radius of first annular region is less than the center radius of second annular region, and the difference of the center radius in two annular concentric zones is 2mm～6mm.

In the said method, at least 3 only incidents successively of bundle described in the step 1), the duration of each incident light is 150 μ s, interval time is less than 1ms.

The device of the harmless fast detecting of a kind of livestock and poultry meat freshness as shown in Figure 3, Figure 4, comprises photodetector unit 100, CPU (central processing unit), display unit 202.

As Fig. 2, shown in Figure 3, described photodetector unit 100 comprises carrier 101, is positioned at the light source of carrier center, at least two photodetectors; Described light source sequentially sends the light of 3 different wavelength, and the duration of incident light is 150 μ s, and interval time is less than 1ms; Described at least two photodetectors that comprise first photodetector 1031 and second photodetector 1032 are annular, and being distributed in the light source is on two concentric rings center of circle, different radii; The lamellar body that described carrier 101 adopts silica gel press mold or injection moulding to form.

As shown in Figure 2, described CPU (central processing unit) comprises microcontroller 1, light source power stabilizing circuit 2, signal processing circuit 3 and storer 4; The drive end of described light source power stabilizing circuit 2 is connected with described light source by cable, and the control end of described light source power stabilizing circuit 2 is connected with the I/O end of described microcontroller 1; At least two photodetectors 1031,1032 in the photodetector unit 100 are connected with the input end of described signal processing circuit by cable; The output terminal of described signal processing circuit 3, control end are connected with input, the output terminal of described microcontroller 1 respectively; Described storer 4 is connected with microcontroller 1, is used for storage of measurement data.

Described display unit 202 is connected with the data terminal of described microcontroller 1, is used to show measurement result.

In said apparatus, described light source sends the light wavelength scope for being 730nm～1100nm; Described light source is LED (Light-Emitting Diode is called for short LED) luminotron or LASER Light Source or the incandescent lamp that optical filter is housed.

In said apparatus, the center internal diameter of first photodetector 1031 of described annular is 10mm～40mm, and the radius of second photodetector 1032 of described annular is greater than first photodetector 1031, and the difference of both radiuses is 2mm～6mm; Described photodetector is silicon photocell or other photodetectors, and its response wave length scope should comprise the wavelength coverage of light source luminescent.

In said apparatus, as shown in Figure 2, described signal processing circuit 3 comprises that pre-amplification circuit 5, low-pass filter circuit 6, sampling hold circuit 7 orders are connected in series; The input end of described pre-amplification circuit 5 is connected with the signal end of described two photodetectors 1031,1032 at least; The control end of described sampling hold circuit 7 is connected with the I/O end of microcontroller 1, and 9 pairs of input signals of the analog-to-digital conversion circuit of microcontroller 1 inside are changed.

In said apparatus, as Fig. 2, shown in Figure 4, comprise that also an input block 203 is connected with microcontroller 1, described input block 203 is one group of button and corresponding circuit.

In said apparatus,, comprise that also a printer interface 205 is connected with microcontroller 1, is used for external printer equipment as Fig. 2, shown in Figure 4.

In said apparatus, comprise also that as Fig. 2, Fig. 4 a serial port 204 is connected with microcontroller 1, be used for to as other equipment transmission datas such as personal computers.

Compared with prior art, the invention has the beneficial effects as follows: method provided by the invention can be monitored the deep layer freshness of livestock and poultry meat, clearly provides freshness parameter and grade, the precision height, and selectivity is strong; Device precision height provided by the invention, the signal to noise ratio (S/N ratio) height, simple in structure, be easy to carry, be suitable for field quick detection.

Description of drawings

Fig. 1 detects schematic diagram for the present invention;

Fig. 2 is the circuit block diagram of the embodiment of the invention;

Fig. 3 is the structural representation of embodiment of the invention photodetector unit;

Fig. 4 is an embodiment of the invention main frame outside drawing;

Fig. 5 is an embodiment of the invention working state schematic representation;

Fig. 6 is an embodiment of the invention method flow diagram.

Embodiment

Below in conjunction with the drawings and specific embodiments the present invention is described in further detail:

According to above-mentioned principle, as Fig. 2, Fig. 3, shown in Figure 4, the device of the harmless fast detecting of a kind of livestock and poultry meat freshness comprises CPU (central processing unit), photodetector unit 100, display unit 202, input block 203.

Photodetector unit 100, as shown in Figure 3, comprise carrier 101, light source and first photodetector 1031 and second photodetector 1032 formed by three LED luminotrons that are fixed on carrier 101 centers (first luminotron 1021, second luminotron 1022 and the 3rd luminotron 1023).On the circle that with the light source is 20mm, fix a ring-like silicon photocell and make first photodetector 1031 for center of circle radius; On the circle that with the light source is 25mm, fix a ring-like silicon photocell and make second photodetector 1032 for center of circle radius.Two photodetectors 1031,1032 for model is 2CR21, wavelength response range is 400nm-1100nm.Carrier 101 is the circular black silicon film of a radius 30mm.The signal end of the drive end of light source and first photodetector 1031, second photodetector 1032 by cable 104, plug 105 respectively with CPU (central processing unit) in light source power stabilizing circuit 2 and the input end of signal processing circuit 3 be connected.In the present embodiment, form three LED of light source, its emission wavelength is respectively 730nm, 830nm, 940nm; In addition, the luminotron among the present invention also can be for more than three, but the light wavelength that these luminotrons send is limited in 3 kinds, and when the LED of each wavelength quantity increased, light intensity increased, and the effect of detection can be better.In the present embodiment, luminotron is 3.

As shown in Figure 2, CPU (central processing unit) comprises microcontroller 1, storer 4, three paths of LEDs light source power stabilizing circuits 2, signal processing circuit 3; Microcontroller 1 adopts the C8051F005 chip; The low-pass filter unit 6 that signal processing circuit 3 comprises the pre-amplification circuit 5 be made up of the TLC27L2 chip, be made of operational amplifier TLC272 chip, the sampling hold circuit of forming by the LF398 chip 7; 12 analog-digital converters of pre-amplification circuit 5, low-pass filter unit 6, sampling hold circuit 7 and microcontroller 1 inside are connected in series successively according to custom circuit.Because annular photodetector has two, so the input end of pre-amplification circuit 1 has 2 the tunnel, connects the signal end of first photodetector 1031 and second photodetector 1032 respectively.The control end of sampling hold circuit 7 is connected with the I/O end of microcontroller, the signal output part of sampling hold circuit 7 is connected with 12 analog-digital converters of microcontroller 1 inside, and the output terminal of 12 analog-digital converters of microcontroller 1 inside is connected with the data terminal of microcontroller 1 inside.Storer 4 adopts flash memory AT45DB321B, is connected with microcontroller 1, is used to preserve result of calculation.

As Fig. 2, shown in Figure 4, display unit 202 adopts one to show the LCD that sell in the place, is connected with microcontroller 1, is used to show the freshness data of microcontroller 1 output; Input block 203 is connected with microcontroller 1, comprises a keyboard, is used for control operations such as measurement, preservation; Present embodiment also is provided with printer interface 205 and is connected with microcontroller 1, is used to connect external printer, detected freshness data can be printed; Present embodiment also is provided with serial port 204 and is connected with microcontroller, is used for to transmitting data as other external units such as personal computers.

For easy to carry, present embodiment is assembled into two parts with above each several part, and a part is a photodetector unit 100, as shown in Figure 3; Another part is the main frame 200 that comprises CPU (central processing unit), display unit 202, input block 203, and as shown in Figure 3, Figure 4, two parts are connected with socket 206 by the plug 105 that is connected to cable 104.

As shown in Figure 4, be the local appearance figure of present embodiment device, comprise housing 201, LCD 202, keyboard 203, serial port 204, printer interface 205, photodetector unit socket 206.

In conjunction with Fig. 1, introduce detection principle of the present invention below:

Fig. 1 represents is surface that photodetection unit 100 the is placed on meat sectional view when surveying.The first ring-like photodetector 1031 is r1 with the distance of light source center, and the second ring-like photodetector 1032 is r2 with the distance of light source center.Curved path A, path B represent the synoptic diagram of photon transport track; The musculature of 301 expression domestic animals raw meat, the adipose tissue of 302 expression domestic animals raw meat, the pork skin tissue of 303 expression domestic animals raw meat.The light that light source sends goes into to inject domestic animals raw meat, sees through muscle layer 301, comes out from muscle layer 301 surface scatterings through scattering, by first photodetector 1031,1032 inductions of second photodetector, and converts electric signal output to.The radius difference of two annular photodetectors, the degree of depth that detects is also just different, as shown in Figure 1, first photodetector 1031 detects mainly is that the degree of depth is the information of the layer at 1/2 r1 place, second photodetector 1032 detects mainly be the degree of depth be 1/2 r2 place layer information.

The principal ingredient of livestock and poultry meat is the vitamin of protein (comprising fribrillin, myosinogen), moisture, lipid, a small amount of extract (nitrogenous and unazotized material), trace etc.For wavelength is incident light in 700nm～1100nm scope, and its main absorbing material is myosinogen and moisture, and their content will influence the absorption coefficient of meat, and the content of other materials mainly influences the scattering coefficient of meat.In meat freshness change procedure, its absorption coefficient and scattering coefficient all can change, and utilize device of the present invention, select the light source of suitable wavelength, according to the long-pending mean value of detected absorption coefficient and scattering absorption, promptly know the freshness of meat.

In the present embodiment, as shown in Figure 3, first luminotron 1021 of light source, the optical wavelength that second luminotron 1022 sends are respectively 730nm, 830nm and are used to detect freshness, the optical wavelength that the 3rd luminotron 1023 of light source sends is 970nm, is used for detection background and absorbs---the detection of moisture absorption.

The synoptic diagram of present embodiment duty as shown in Figure 5.Detected livestock and poultry meat 300 comprises musculature 301, adipose tissue 302, pork skin tissue 303, photodetector unit 100 lies on the detected livestock and poultry meat 300, be positioned at three luminotrons 1021 of microcontroller 1 control of the CPU (central processing unit) of housing 201,1022,1023 to be docile and obedient preface luminous, photodetector 1031,1032 detect the light that scatters out from livestock and poultry meat 300, this light signal is transformed into electric signal, send to the pre-amplification circuit 5 of CPU (central processing unit), pre-amplification circuit amplifies the electric signal that photodetector sends, be input to the low-pass filter unit 6 that operational amplifier constitutes, deliver to 12 analog-digital converters of microcontroller 1 inside by sampling hold circuit 7, convert microcontroller 1 manageable digital signal to, through the processing of microcontroller 1, show detected freshness result by LCD 202; Microcontroller 1 is stored in the result in the storer 4.

With reference to the device that the foregoing description provides, a kind of livestock and poultry meat freshness can't harm method for quick, as shown in Figure 6, comprises the steps:

1, utilizes the harmless device for fast detecting of the livestock and poultry meat freshness that provides in the above-mentioned specific embodiment, the light of 3 kinds of wavelength (730nm, 830nm, 970nm) with 3 bundle known strength are injected meat inside from the meat surface, detect the light intensity of three kinds of wavelength that come out from the meat surface scattering on the meat surface in two zoness of different.

2, calculate by following formula and respectively restraint the diffusion of light ratio

$R_k^x=\frac{I_k}{I_{\mathrm{kr}}^x},$

In the formula, k=1,2 ... the footnote of the light source of 3 expression different wave lengths: I _kIt is the light intensity of k bundle light incident;

The organization internal scattering that is k bundle light process object to be detected is afterwards in the detected diffusion light intensity of meat surf zone, x=1,2; 1 expression, first photodetector, 2 expressions, second photodetector; R is the sign of diffused light;

3, to the light of same wavelength, but detected diffusion rate value carries out data operation by following described formula on the zones of different:

$\&PartialD;R_{{\mathrm{\&lambda;}}_K}=\log \frac{I_k}{I_{\mathrm{kr}}^2}-\log \frac{I_k}{I_{\mathrm{<figure-callout\; id="1"\; label="kr"\; filenames="C200510059937E00132.png"\; state="\{\{state\}\}">kr</figure-callout>}}^1},$

${\mathrm{\&mu;}}_a^{{\mathrm{\&lambda;}}_k}{\mathrm{\&mu;}}_s^{{\mathrm{\&lambda;}}_k}=\frac{{(\ln 10\frac{\&PartialD;R_{{\mathrm{\&lambda;}}_k}}{\mathrm{\&Delta;\&rho;}}-\frac{2}{\mathrm{\&rho;}})}^2}{3}$

${\mathrm{fre}}_{\mathrm{index}}=\frac{1}{3}\underset{k=1}{\overset{3}{\mathrm{\&Sigma;}}}{\mathrm{\&mu;}}_a^{{\mathrm{\&lambda;}}_k}{\mathrm{\&mu;}}_s^{{\mathrm{\&lambda;}}_k}$

In the formula, λ k represents different wave length; Δ ρ is the centre distance in two zones; ρ is and the zone of incident beam apart from each other and the distance of incident beam; μ _aBe absorption coefficient, μ _sBe scattering coefficient, represent freshness with the product mean value of absorption coefficient and scattering coefficient, this index is fre _Index

4. according to fre _IndexValue divide three grades with the freshness of meat: fre _Index〉=0.075mm ^-2Expression one-level freshness, 0.075mm ^-2Fre _Index〉=0.055mm ^-2Represent secondary freshness, fre _Index＜0.055mm ^-2Expression is rotten.

In the said method, 3 described in the step 1 bundle only incident successively, survey the diffusion light intensity successively; The duration of each incident light is 150 μ s, and be 1ms interval time.

Utilize device provided by the invention, tested butcher, acid discharge 24 hours is with interior chilled pork with the grade of freshness of its storage after 12 days, record its grade of freshness and be respectively: 0.09mm ^-2(one-level freshness), 0.0521mm ^-2(going bad), the reliable and readability of its testing result.

It should be noted last that: above embodiment is the unrestricted technical scheme of the present invention in order to explanation only, although the present invention is had been described in detail with reference to the foregoing description, those of ordinary skill in the art is to be understood that: still can make amendment or be equal to replacement the present invention, and not breaking away from any modification or partial replacement of the spirit and scope of the present invention, it all should be encompassed in the middle of the claim scope of the present invention.

Claims (9)

1. the harmless method for quick of livestock and poultry meat freshness is characterized in that, comprises the steps:

1) wavelength with at least 3 bundle known strength are that the light of the different wave length of 730nm, 830nm or 970nm is injected meat inside from the meat surface, comprise the light intensity that detects the different wave length that scatters out in the meat at least in two zoness of different of first area and second area on the meat surface;

2) calculate by following formula and respectively restraint the diffusion of light ratio

$R_k^x=\frac{I_k}{I_{\mathrm{kr}}^x}$

In the formula, k=1,2 ... n, the footnote of the light source of expression different wave length, n 〉=3; I _kIt is the light intensity of k bundle light incident;

The organization internal scattering that is k bundle light process object to be detected is afterwards in the detected diffusion light intensity of meat surf zone; X=1,2; 1 expression first area, 2 expression second areas; R is the sign of diffused light;

3) to the incident light of same wavelength, but detected diffusion rate value carries out data operation by following described formula on zones of different:

${\&PartialD;R}_{{\mathrm{\&lambda;}}_K}=\log \frac{I_k}{I_{\mathrm{kr}}^2}-\log \frac{I_k}{I_{\mathrm{kr}}^1},$

${\mathrm{\&mu;}}_a^{{\mathrm{\&lambda;}}_k}{\mathrm{\&mu;}}_s^{{\mathrm{\&lambda;}}_k}=\frac{{(\ln 10\frac{{\&PartialD;R}_{{\mathrm{\&lambda;}}_k}}{\mathrm{\&Delta;\&rho;}}-\frac{2}{\mathrm{\&rho;}})}^2}{3}$

${\mathrm{fre}}_{\mathrm{index}}=\frac{1}{3}\underset{k=1}{\overset{3}{\mathrm{\&Sigma;}}}{\mathrm{\&mu;}}_a^{{\mathrm{\&lambda;}}_k}{\mathrm{\&mu;}}_s^{{\mathrm{\&lambda;}}_k}$

In the formula, λ k represents different wave length; Δ ρ is the centre distance in two zones; ρ is and the zone of incident beam apart from each other and the distance of incident beam; μ _aBe absorption coefficient, μ _sBe scattering coefficient, represent freshness with the product mean value of absorption coefficient and scattering coefficient, this index is fre _Index

4) according to fre _IndexValue divide three grades with the freshness of meat: fre _Index〉=0.075mm ^-2Expression one-level freshness, 0.075mm ^-2Fre _Index〉=0.055mm ^-2Represent secondary freshness, fre _Index＜0.055mm ^-2Expression is rotten.

2. livestock and poultry meat freshness according to claim 1 can't harm method for quick, it is characterized in that, at least two zones are to be two annular regions that center radius is different at center with the incident beam described in the step 1), the center radius of the annulus of second annular region is 10mm～40mm, the center radius of first annular region is less than the center radius of second annular region, and the difference of the center radius in two annular concentric zones is 2mm～6mm.

3. livestock and poultry meat freshness according to claim 1 can't harm method for quick, it is characterized in that, and the only incident successively of the bundle of at least 3 described in the step 1), the duration of each incident light is 150 μ s, interval time is less than 1ms.

4. the harmless device for fast detecting of livestock and poultry meat freshness comprises photodetector unit, CPU (central processing unit), display unit;

Described photodetector unit comprises carrier, is positioned at the light source of carrier center, at least two photodetectors; Described light source is LED luminotron or LASER Light Source or the incandescent lamp that optical filter is housed, and described light source sequentially sends the light of at least three kinds of different wave lengths; The lamellar body that described carrier adopts silica gel press mold or injection moulding to form;

Described CPU (central processing unit) comprises microcontroller, light source power stabilizing circuit, signal processing circuit and storer; The drive end of described light source power stabilizing circuit is connected with light source by cable, and the control end of described light source power stabilizing circuit is connected with the I/O end of described microcontroller; At least two photodetectors in the described photodetector unit are connected with the input end of described signal processing circuit by cable; The output terminal of described signal processing circuit, control end are connected with the I/O end of described microcontroller respectively; Described storer is connected with microcontroller, is used for storage of measurement data;

Described display unit is connected with the data terminal of described microcontroller, is used to show measurement result;

It is characterized in that described signal processing circuit comprises that pre-amplification circuit, low-pass filter circuit, sampling hold circuit are connected in series in proper order; The input end of described pre-amplification circuit is connected with the signal end of described two photodetectors at least; The control end of described sampling hold circuit is connected with the I/O end of microcontroller, and the analog-to-digital conversion circuit of microcontroller inside is changed input signal; The light of at least three kinds of different wave lengths that described light source sends, its wavelength is respectively 730nm, 830nm or 970nm.

5. livestock and poultry meat freshness according to claim 4 can't harm device for fast detecting, it is characterized in that,

Described at least two photodetectors are annular, and forming with described light source is the donut center of circle, different radii; The center radius of first photodetector of described annular is 10mm～40mm, and the center radius of second photodetector of described annular is greater than the center radius of first photodetector, and the difference of both radiuses is 2mm～6mm.

6. livestock and poultry meat freshness according to claim 4 can't harm device for fast detecting, it is characterized in that, described photodetector is a silicon photocell, and its response wave length scope should comprise the wavelength of light source luminescent.

7. livestock and poultry meat freshness according to claim 4 can't harm device for fast detecting, it is characterized in that, comprises that also an input block is connected with described microcontroller, and described input block is one group of button and corresponding circuit, is used for measuring, preserving control operation.

8. livestock and poultry meat freshness according to claim 4 can't harm device for fast detecting, it is characterized in that, comprises that also a printer interface is connected with described microcontroller, is used for external printer equipment.

9. livestock and poultry meat freshness according to claim 4 can't harm device for fast detecting, it is characterized in that, comprises that also a serial line interface is connected with described microcontroller.

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