CA1221848A - Method for quality control of products from fish, cattle, swine and poultry - Google Patents

Abstract

CANADIAN PATENT APPLICATION

OF

SVEND AAGE JENSEN, LARS MUNCK, POUL SIGSGAARD
AND
HANS HENRIK HUSS

FOR

METHOD FOR QUALITY CONTROL OF PRODUCTS FROM FISH, CATTLE, SWINE AND POULTRY

Abstract of the Disclosure A method for quality control of products from fish, meat, cattle, swine and poultry, for instance for con-trolling a process for treating or handling such pro-ducts. The product to be subjected to quality control, or a sample thereof, is exposed to electromagnetic ra-diation within the range of about 325-360 nm, preferably about 340 nm, and any flourescent radiation emitted by the product as a result of this irradiation, is ana-lysed for identifying characteristic fluorescence from la biological components in the product or a sample there-of, the presence of such biological components deter-mining the quality of the product. The quality control is carried out in dependence upon the analysis result, Analysis carried out in the wavelength range of about 365-490 nm permits identification of characteristic fluorescence from bones, cartilage, connective tissue and/or fat.

1b

Description

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~lL22:1~1!il~1!3 The preseli~ invention relates to a method f~r quall-ty control o~ products from fi.~ll, cattle, swine and poultry, for instance ~or controlling a process for treating or handlinq such pro~ucts, The fish processing ind~lstry p~y~ ~reat attention to the task of removing the bones from the fish, The removal of bones, e,g, in ~onnection with filleting, is carried out in machines with a subs~quent manual tri~nirl~ for removing any remaining bones which may be observed with the eye or ~elt by the fingers. Such manual detecting met~ods are very slow and unreliable, which means that flsh products often escape the control with remaining bones undetected. Many Pish products which have been boned are delivered in th~ ~rozen st~te in lar~e packag~s to wholesalers or the cannln~ industry who will als~ carry out the above-des~r~bed manual con trol on ~ random sampl~ basis for a small p~rt of the package, to assess ~he presen~ of any remaining bones in the p~ckage~ If it is ~ound in this control that the content~ of bone exceed a predetermined value, the entire package is dis~arded, which means a considera~le economic loss to the supplier.
In ~he preparation o~ meat produ~ts by cutting animals and in the m~king of mixed meat produrts, su~h as sausage, brawn, minced meat, p~t~ etc., b~th as pe-risha~le ~nd canned foods, one has la~ely placed still higher demands on t~e decl~ration o~ the contents of the products. Anal~ses in this respect have hitherto been ~

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performed s~l~stantially on the basis of the chemical constituent~ of the pro~uc~, such as fat, protein, as.l, water etc,, and it nas been very time-consuming and dif f lcult, not to say impos~i~le, qu~nti~atively to ~efine the composi~ion of the product on the basis of the animal ~lssue c~mponents which are of ~reat impor-tance fQr the organoleptic quality, s~ch ac. tenderne~s, or the nutxi~ional ~u~lity, such as digestibility. It i~ also evident that the economic value.s in pure meat are considerably hlgher th~n in other animal components, such as fat, eonnective tissue, car~ilage, ~nd that th~rc is thus an economic incitemen~ toward being able a~curately to determine the composition o~ the meat products, so that the raw products can be better uti-lised in ~he pro~essing factories. ~ith an accurate method Por detecting the most importan~ animal compo-nents it would be possi~le on a large scale to ~ontr~l automatic trimming apparatuses for optimal use of the valuable meat in the animal parts whicll are dl~ficult to cut manually ln a cost-eP~ectivc way.
One object of the inven~ion is to provide a quick ~nd r~lia~le method for d~tec~ing bones in fish products.
Another ohject of the invention is to provlde a ~uick an~ reliahle method for detecting animal compo-n~nts, such as bone, cartilage, conneçtive tissue, fat and mea~ (muscles) in meat products~ including poul-try p~oductsl which detection should preferably also allow quantita~ive de~ermination o at least one of ~iEF~O TELESOF'EF: ~a~ 1 as; 6~ ! S~ S~-50:~ao~~9;~ -R I Q 5 ~15 ! f~

~2Z~8~8 ~hc aforementioned compone~ts~
With these o~jects in mind, the main purpose of the invention is ~o provide a method for the a~sve-menti~ned detections which per.~its a more rapid and at least equally accurate quality control o~ fish and meat products as comp~ed with prior ~rt methods, ~or in~tance for controlllns processes for treating and handlin~ fl~h and meat products, A~cording t~ the invention, these ob~ects are achiev-ed in that the product to be subjected to quality con~
trol, or a sample thereof, is exposed to elec~romagnet~c radiation within the ran~e of about ~25-360 nm, prefer-ably about 340 nm, that any ~luorescent radiation emltted by the product as ~ result of this irradiation, ls ana-lyscd 4cr identifyin~ char~cterlstic fluor~scence from biological components in the product or a sample there-of, the presence of such biological ~omponents deter-mining the quallty o the pro~uct, and tha~ sald quality control is carried out in dependence upon the analysis result.
The invention is based on the surprlsing dls~overy that irradiation of fish sampLes ~itll elec~romagneti~
radl~tion wl~hin the UV range permits detectlng bones in the fish sample, and m~re preclsely that irradiation o fish samplos at about 340 nm ~auses a chara~teris-tic and visi~le fluoresc~nce also fram a fish ~one which is embedded in the flesh of the fish~ and further on the surprising discovery that UV irradiation of ~eat `;E~Ci -rEl E~ F ~ b- L-=~
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producrs contairir.g bone, carti.lage, connective tissue an~ fat permits d~t~cting the~.e anln~al compon~nts in t~e produ~ts, and m~re preclsely that the irradiation of animal bone, c~rtilage, connective tlssue and fat with ~ ht o~ about 340 nlr. causes a characteristlc and visible ~luorescence rom bone, cartilage, connec-tive tissl~e and a~, also ~hen the bone is surround~d by meat~
rrhusl when a sample of cod fillets ~ith bones were irradia~e~ with electroma~netic radiation at about 340 nm, it was possi~l~ with the eyo to clearly observe in the sample distinct s~reaks fluores~ing in blue-vlolet against a li~ht beig~ background, and in A control the streaks were clearly ldentified as fish bones and the back~round as ~ish 1esh. The same ~olours ~Pre obtained wh~n stu~ying this irrad~ation of fish ~one only and o~ ~ish f lesh o~ly, It was also posslble in thi~ manner ~o detect fish bones located 1J1 fish fle~h at a few millimetrcs' depth.
When irradiating a bone-containinq meat sample with electroma~netic radiation of about ~40 nm, one could thus visuall~ clearly perGeive a deep blue fluo-roscent portion ~qainst a dark ~ackground, In a ~ontrol, the fluorescent portion was clearly identified as bone and the background as m~a~.
Similarly~ by elec~romagnetic irradiatio~ at ~bou~
340 nm o a cartil~ge- or connec~i~e tissue-containin~

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~Z~348 meat sample, lt was possible visually to identify ca~-tila~e, connecti~e tissue and meat.
When irradiating a fat-containing meat sample with elecLroma~netic radiation of about 340 nm, it was further possihle ~isually to clearly perceive a blue and ye7low fluoroscen~ portion agAinst a dark background. In a controlr the fluorescent portlon could be clearly iden-~i~ied as ~at and the back~round as meat, As intimated above, the corresponding fluorescenc~
emisslon characteristics are obtained on a UV irra~ia-tion at about 340 nm of pure bone, cartllage, connec-tive tissue~ fat and meat samples.
Reference is now made to the accompanying drawings, in which Fi~. 1 is an excitation spectrum for fish bone at an emission of 39~ nm;
Fig, ~ is an emission spe~rum ~or fish bone and fish flesh at an excl~ation of 340 nm;
Fig, 3 is an excitation sp~ctrum for cartila~e ~rom pi~ at an emis~ion of 3YO nm;
Fig. 4 is an emission spectrum ~or bone fro~ pig at an excitatlon of 340 nm;
Fi~, 5 is an emlssion spec~rum for cartilage ~rom chicken ~t ~n excitation o 34~ nm;
Fig. 6 is an emission spectrum for connect~ve tis-sue from ~ow at an ~xcitation of 340 nm;
Fig, 7 is an emissiol~ spectrum for fat from cow at an excitation of 340 nm;

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Fig, 8 is an emisaion ~pectrum for mea~ ~rom cow at an excitation cf 340 nm;
Fig, 9 schematically shows a system for c~rrying out the method accordlng to th~ invention in a produc-tion/processing lin~;
In order to i~vestigate optimum emi~sion and excita-ti~n wa~elengths for the ~etection of flsh bone, fish ~one and fish flesh were studied in a spectrofluorometer.
'rhe~ cxcitation spectrum of the ~ish bone had a peak at about 340 nm~ the excitation limits being at about 325 nm and about 355 nm, Fig. 1, and the fluorescence emission spectrum at 3gO nm ~xcltation had a péa~ At about 3gO nm~ Fig, 2, At an irradlation of fish flesh at 34U nm, there was hardly obtalned any detectable fluorescence intensity ~rom the flesh. This result is illustrated in ~ig, 2 cor~firming visible ~luorescence from ~ish bone at an irradiation of 340 nm, It has thus been established ~hat an irradiation of fish parts with electromagnetic radiation wlthin a wavelength range of 325-355 nm unam~iguously reveals the presence of any bones by the re~ulting charac~eris-tic ~luorescence of the bone.
In order to inves~igate op~imum emission and ~xci-t~tlon wavelengths ~or the detee~lon of bone~ cartilage, connective tissue and fat in meat products (lncluding poultry)l bone, eartilage~ connective tissue, fat and meat ~ere s~died in a spec~rofluorometer. The Qxclta tion spectr~m from bone~ cartilage, connective ti~sue , E~CI^~ TELEc-OF lEF 4q5; ~ c5; 5~ . 6~51~,- G' .'C,-,~S~
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and fa~ had a peak at abou~ 340 nm and the excitation limits were at about 325 nm and about 360 nm, which is illustr~ted in Fig. 3 by a measurement on cartllage ~LOm pig~ At an irradiation of bone from pig, cow, lamb and chicken a~ a~o~t 340 nmt fluorescence emissiQn sp~e-tra were caused with ~ peak at ~bout 3~0 nm ~nd a minor peak at abo~t 4i5 nml which is illustrated in Fig, 4 by a measurement on bone from pig. ~t an l.rradiatlon of cartilage from plg, cow and cllicken a~ about 340 nm, fluorescence emission spectra were ~aused with a peak at about 3~0 nm and a minor peak at 455 nm, which is illus~rated in Fig. 5 ~y a measurement on cartllage ~rom chicken, At an irradiation of connect~ive ~issue at about 340 nm, a fluo~esc~nc~ emission spectrum was caused with a peak at about 390 nm and a minor peak at about 455 nm, which is i~lustrated in Fig, 6 by a measurem~nt on connecti~e tissue from ~ow. At an ir-radiation of fat ~rom pig, cow and chicken at about 340 nm, ~luorescence emission spectra were caused with a peak at about ~90 nm and a peak a~ abaut 475 nm, which is illustrated in ~ig. 7 by a measurement ~n fat fxom cow.
At an irradiation of me~t ~rom pig, cow and chicken at about 340 nm, no fluoresGen~e was caused, which is ill~strated in ~lg. 8 ~y a mea~urement on meat ~rom cow .
It can thus be established that electromagnetic radiation in the wa~elength range of 325-360 nm unam-~Ef~ TELE~ PlEF~ 4~5; S~ 5; 6:5~ 4~ 51~5~,q8~

~Z;~ 8 bl~uously reveals the presence of any bone, c~rtilage, conrlectlv~ ti~u~ an~ faL in ~ t pro~ucts (~ncl~ldinq pc)ultry) by the e~.lssion of characteristic ~luorescence.
An apparatus for carrying out the method may in-cl~de a screened box containing a source of radiatlon or a combination of radiation sou~ce and filter for emitting ele~t3:oma~netic radiation in the range of about 325-360 nm, pre~erably with a peak at about 340 nm.
The box further has one or more emission ~ilters whi~h transmit elec~romagnetic radiati~n i~ the r~nge of about 365~4~0 nm, wikh peaks ~t 390 nm, 455 nm and 475 nm, the last two wavelengths l~elng usable for distingulsh-in~ the detection of bone, cartilage, connective tissue from that o~ fat in meat, ~he box further has opening devi~es ~or inserting and extrac~in~ samples, For auto-matic lnstrument control, the ~pparatus ma~ b~ provided wlth a photomul~iplier or amplifler device with inten-sity threshold relays which are opera~l~ connect~d to a microprocessor. This permits obtaining a digital trig-gering ~or controlling a control mechanism having se-veral alternative functions ~ such as expelling unaccept-able products Prom a conveyor belt or indicatin~ the purity of a fish or meat product in respect of the meat o~ ~les~ conten~, which ~an b~ directly printed on ea~h paGkage as consum~r's informatlon~ Fur~her, the unde-~ired animal compOnentS c~n be dete~ted by an optlcal system which is provided wit~ said filter, and the de-tected image can be electronically txansmitte~ via a TV

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ec~uipme~t tc an i~r.age analyscr, A cu~tin~ and trln~rnin~
machine can then ~e controlle~ from the image analyser on the basi~ of the image su~h that optimum trimming of th~ fish or meat product can be au'cor.a~cic~lly ob-tained~ The resul~ of the ~mage analysis is also con-vertible in a per se known manner into a cluantitative determination, in th~ instant case of bone, cartilage ~nd connec~ive tissue, taken together) and/or of fat separa~ely and of meat ~muscles), the p~esence o~ which is de~ermined quantitativ~ly as a di~ference ~etween the total area ~volume) of the meat product in th~ field of visiorl and the sum o~ th~ ar~as tvolumes) of ~one, cartilage, connective tis5ue and fat. This ~ype of quan-ti~tive determination ~ay be inaccurate for ~hick or coarse meat products, If an accur~te analysis is deslr-able, the quantitative analysis of such products is therefore prcferably carried out with the aid of spec-trof luorome~ry on a minced and suspended sample of the meat product.
Fi~. 9 illustr~tes schematically a system Por auto-matic ~ish fillet control in line downstream of a ~
le~in~ machine not shown. The system comprises a U-shaped light box 1 and ~ d~tector 2, said light box straddling ~ onveyor belt 3 on which f illets 4 are advanced from the filleting machine for q~ality control . The light box 1 contains a light source 5 for ~40 nm radiation which is so positioned in the box that lts radiatlon impinges upon the fill~ts 4 succcssively advanced on ln >iE~I~ TELE~ F ~5; ~ ,r,; ?: ~r'~!l ; n-~ t~ --rr~ ; r 1 5 ! ~ f ~

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the conve,lor bel~ 3~ Cor.nected in series with the photo-detectcr 2 W-liCh i5 connected to an aperture in the top of the box, are optics 6 and filters 7 for letting through 390 ntn li~ht which~ by the excitation irradia-tion at 3qO nr,, has beell emlt~ed by a f il.let; containir~
bones, Thc detector 2 is sensitive to 3~0 nm light, and its output signal is proportional to t~e intensity of de~ected 390 nm light, which intensity in its turn is proportional to the amount o~ bones in the flllet, A
signai processor ~ receives the outpu-~ signal from the detector 2, and the outpu~ si~nal of the processor is used ~or ~ctivation o~ a piston-cyt inder unit 9 which i5 disposed adjacent the conveyor belt 3 downstream of the light box 1 and e~ects from the conveynr b~lt ~ny f illet containin~ bones or unaccept~bly many bones, ~ccording to a threshold value settlng in the signal processor,

Claims (23)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method for quality control of products from fish, meat, cattle, swine and poultry, for instance for controlling a process for treating or handling such products, characterised in that the product to be subjected to quality control, or a sample thereof, is exposed to excitation electromagnetic radiation within the range of about 325-360 nm, preferably about 340 nm, that any fluorescent radiation emitted by the product as a result of this irradiation, is analysed for identifying characteristic fluorescence from biological components in the product or a sample thereof, the presence of such biological components determining the quality of the product, and that said quality control is carried out in dependence upon the analysis result.

2. A method as claimed in claim 1 for quality control of fish products, characterised in that said analysis is carried out with emitted radiation in the wavelength range of about 265-450 nm for identification of character-istic fluorescence from fish bones.

3. A method as claimed in claim 2, characterised in that the said analysis is carried out with emitted radiation at 390 nm.

4. A method as claimed in claim 1 for quality control of meat products from cattle, swine and poultry, character-ised in that said analysis is carried out with emitted radiation in the wavelength range of about 375-490 nm for identification of characteristic fluorescence from bones, cartilage, connective tissue and/or fat.

5. A method as claimed in claim 4, characterised in that said analysis is carried out with emitted radiation at 390 nm and/or 455 nm for identification of characteristic fluorescence from bones, cartilage and/or connective tissue.

6. A method as claimed in claim 4, characterised in that said analysis is carried out with emitted radiation at 390 nm and/or 475 nm for identification of characteristic fluorescence from fat.

7. A method as claimed in one of claims 4, 5 or 6 characterised in that the said analysis comprises a quantity determination of bones, cartilage, connective tissue taken together and/or of fat and, via these quantity determinations, of meat, said quantity determination being carried out by means of fluorescent image analysis or spectrofluorometry or by means of a photodetector on whole or minced products.

8. A method as claimed in one of claims 4, 5 or 6, characterised in that the said analysis comprises a quantity determination of bones, cartilage, connective tissue taken together and/or of fat and, via these quantity determinations, of meat, said quantity determination being carried out by means of fluorescent image analysis or spectrofluorometry or by means of a photodetector on whole or minced products, the products to be sujected to quality control being carried on a conveyor past a quality determining instrument, the analysis result being used for controlling a device for removing qualitatively unacceptable products from said conveyor.

9. A method for assaying for fish bone in edible fish flesh containing fish bone, said method comprising exposing fish flesh to excitation electromagnetic radiation having a wavelength of about 325 nm to about 355 nm to produce fluorescent radiation from said flesh; and sensing the fluorescent radiation having a wavelength of about 365 nm to about 450 nm characteristic of fish bone in said flesh.

10. Method according to claim 9 wherein the excitation electromagnetic radiation has a wavelength of about 340 nm.

11. Method according to claim 10 wherein the emitted radiation has a wavelength of about 390 mn.

12. Method according to claim 9 wherein the fish flesh is minced.

13. Method according to claim 9 wherein the fish flesh is a cod fillet.

14. A method for assaying for non-nutritional components selected from the group consisting of bone, cartilage, connective tissue or fat in edible flesh containing at least one of said components from an animal selected from the group consisting of pig, cow, lamb and chicken, said method comprising exposing the flesh to excitation electromagnetic radiation having a wavelength of about 325 nm to about 360 nm to produce fluorescent radiation from said flesh; and sensing the fluorescent radiation having a wavelength of about 390 nm or about 455 nm characteristic of said non-nutritional component.

15. Method according to claim 14 wherein the excitation electromagnetic radiation has a wavelength of about 340 nm.

16. Method according to claim 15 wherein the emitted radiation has wavelengths of about 390 nm and about 455 nm and radiation of both wavelengths is detected.

17. Method according to claim 14 wherein the flesh is minced.

18. A method for assaying for fat in flesh from a pig, cow or chicken containing fat, said method comprising exposing the flesh to excitation electromagnetic radiation having a wavelength of about 325 nm to about 355 nm to produce fluorescent radiation from said flesh; and sensing the fluorescent radiation having a wave-length of about 390 nm or about 475 nm characteristic of fat in said flesh.

19. Method according to claim 18 wherein the excitation electromagnetic radiation has a wavelength of about 340 nm.

20. Method according to claim 19 wherein the emitted radiation has wavelengths of about 390 nm and about 475 nm and radiation of both wavelengths is detected.

21. Method according to claim 18 wherein the flesh is minced.

22. A method for assaying edible flesh from an animal selected from the group consisting of pig, cow and chicken, said flesh containing fat and at least one non-nutritional component selected from the group consisting of bone, cartilage and connective tissued, said method comprising exposing the flesh to excitation electromagnetic radiation having a wavelength of about 325 nm to about 360 nm to produce fluorescent radiation from said flesh;
sensing the fluorescent radiation having a wave-length of about 390 nm and about 475 nm characteristic of fat in said flesh; and sensing the fluorescent radiation having a wave-length of about 390 nm and about 455 nm characteristic of non-nutritional components in said flesh.

23. Method according to claim 22 wherein the excitation electromagnetic radiation has a wavelength of about 340 nm.