Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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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
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~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
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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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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
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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-
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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
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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,
