Post on 25-Mar-2018
Evaluation of a Prototype Fish Cleaning Machine With Proposals for aCommercial Processing Line
J. M. MENDELSOHN and J. G. CALLAN
Background
Heading and gutting small fish byhand is both time consuming andlabor intensive, making it an expensive operation. In cases where specialhandling is absolutely necessary orwhere the products can command ahigh price, processing fish by handmay be economically feasible; butwhere the fish product has to be competitive in price with other high protein foods, or the value of the fisheryproduct is relatively low, machineprocessing must be used. Not onlymust the economic aspect be considered but where the need to produce aheaded and fully cleaned fish forfurther processing is important, amachine must clean the fish completely in order to be justified. This isespecially evident where the fish mustbe headed and completely freed ofviscera and belly lining, particularly
J. M. Mendelsohn and J. G. Callan are with theGloucester Laboratory, Northeast FisheriesCenter, National Marine Fisheries Service,NOAA, Emerson Avenue, Gloucester, MA01930.
ABSTRACT-A prototype heading andcleaning machine for small whiting wasevaluated under commercial conditions.The major finding was that the machine issound in theory and principle but needssome of its components redesigned forhigh speed production. Throughput wasfound to be about 2,250 fish/hour (lessthan was expected) of which about 95 per-
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when the lining is pigmented as in thecase of whiting, Merlucciusbilinearis, prior to processing in ameat/bone separator. As a solution toheading and fully cleaning whiting, aLaPine Model 22 smelt processingmachine 1 was extensively modified(Mendelsohn et aI., 1977).
Preliminary Results
The modified machine (Fig. I) waslaboratory tested for processing various sizes of whiting 8-16 inches(20.3-40.6 cm) in length in test runsinvolving 500 pounds (225 kg) to5,000 pounds (2,250 kg) of fish. Fishoutside of this size range were culledand discarded because the processingeffectiveness of the machine was notacceptable for these. Since themachine was designed to handle fishthat varied in length by no more than4 inches (10.2 cm), we adjusted themachine to handle fish in the range of10-14 inches (25.4-35.6 cm) because
'Reference to trade names or commercial firmsdoes not imply endorsement by the NationalMarine Fisheries Service, NOAA.
cent were cleaned well enough for furtherprocessing or to be frozen directly as areverse-butterfly or pan-ready product.
From these tests, we believe that newmachines could be built to handle fishfrom 6 to l8 inches (l5.2-45.7 em) atproduction rates up to l2,000 fish/hour.For increased production, three machinesshould be used together in a system com-
this is the center of the 8- to 16-inch(20.3- to 40.6-cm) range.
The results of the laboratory testsindicated that the prototype machinehad a capacity of about 3,600 fish/hour and that it could effectively headand clean the fish and remove most ofthe peritoneum (black belly lining) ofwhiting. Subsequent trial runs beforeindustry further demonstrated themachine's potential, and only anevaluation of the machine's performance under actual commercial conditions was necessary to encourage itsassimilation by industry. Coordinatedby the authors, the machine wastested by a Boston processor undercontract to the New England FisheriesSteering Committee (NEFSC)2.
Processing in Commercial Plant
Gloucester-landed whiting werebrought to the Boston commercial fishprocessor for heading and cleaning bythe modified LaPine machine. The
2NEFSC is a nonprofit educational associationorganized to further the interest and welfare of allthose engaged in the domestic New Englandfishery (Anonymous, 1977).
prising auxiliary equipment. Eachmachine would process a specific sizerange offish with an expected total outputfrom the three machines of about 36,000fish/hour. The fish would be scaled,graded, oriented, conveyed, headed, andcleaned automatically with maximum recovery of edible fish flesh and withminimum waste.
Marine Fisheries Review
Figure I. - Prototype fish heading and cleaning machine.
size range of the fish varied from wellbelow 6 inches (15.2 cm) to wellabove 18 inches (45.7 cm). Althoughthe machine was laboratory tested fora size range of 8-16 inches (20.3-40.6cm), an attempt was made to head andclean whiting between 6 and 18 inches (15.2 and 45.7 cm) to determineif the enlarged size range could be acceptably accommodated.
Those fish below 6 inches (15.2cm) and above 18 inches (45.7 cm) inlength were culled and discarded.Again, as in the laboratory experiments, we adjusted the machine tohandle the middle of the range 10-14inches (25.4-35.6 cm). Once set, thecontrols were not changed during theruns.
This sequence was followed in atypical run using either penned 3 (5-6day old) or day-boat (1-2 day old)whiting in the heading and guttingmachine in the commercial fish processing plant:
I) Boxed iced whiting, landed inGloucester, Mass., in the morning,were trucked to the plant in the afternoon and held overnight in a cooler at35"F (rC).
2) The next morning, the fish werescaled in a commercial rotary scaler.
3) The scaled fish were manuallyplaced on the wooden cleated conveyor leading to the heading and gutting machine.
4) Every fish was headed and gutted by the machine.
5) Each fish was inspected as it leftthe machine. Uncleaned fish werehand-cleaned or discarded.
6) If the fish were to be sold aspan-ready (reverse-butterflied) fish,they were frozen in 10 pound boxes.
7) If the fish were to be deboned,they were transferred to a conveyorleading to the Bibun Model 18 meat/bone separator. The minced fish fleshwas collected and made into 18.5pound minced blocks and plate fro-
3Penned whiting refers to fish from boats thathave been out fishing 4 to 5 days. These whitingare 5 to 6 days old prior to processing. Day-boatwhiting refers to fish from boats out fishing foronly I day. These fish are I to 2 days old prior toprocessing.
January 1980
zen. Frozen fish blocks are used as theraw material in the manufacture offish sticks, portions, and other specialty items (Ryan, 1978).
Results and Discussion
Operation UnderCommercial Conditions
Operation of the machine undercommercial conditions indicated thatwhile the theory and the principlesemployed were sound and effective,the theoretical capacity of 3,600 fish/hour could not be met. The maximumprocessing rate reached was about2,700 fish/hour with four peopleoperating the machine-two peoplefeeding the machine, one person keeping the machine running properly, andone person inspecting the fish. Evenat this rate, the machine had to bestopped for about 4-5 minutes every25 minutes for a complete wash-downto remove viscera collecting at thecleaning wheels which would otherwise impede the smooth flow of fishthrough the machine.
With a throughput of 45 fish/minutefor 25 minutes operating time and almost 5 minutes cleanup, the machine
would head and gut about 2,250 fish/hour. With the weight of the whitingaveraging about one-half pound, themachine throughput was about 1,125pounds/hour. Even if the machinethroughput could be doubled by experienced operators, it would fall farshort of the production rate desired bythe larger processors.
Still, the economics of using themachine compare favorably withmanual gutting and heading of whiting. The speed of an experienced person that hand processes whiting isabout 30 fish in 9 minutes or about200 fish (100 pounds)/hour. Even if aperson could continue to handle 100pounds/hour throughout the day, theprototype machine works over II timesfaster, with no loss in speed as mightoccur with a human as the day wearson. Thus while the machine might fallshort of commercial processor expectations, the fact that one machine plusfour workers can replace II skilledcutters is evidence that it still representsan economic advantage. Also, thequality of the fish remains constant inmachine processing, whereas the quality of the manually processed whiting
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is variable and generally poorer, especially as the workday wears on.
Yield Recovery
Starting with whole whiting, the recovery of headless and fully cleanedreverse-butterfly whiting (pan-ready)was determined. Results from twoseparate runs showed that from a mixture of sizes of whole whiting (6-18inches or 15.2-45.7 cm), yields of46.0 percent and 46.3 percent wereobtained. These yields were approximately 5 percent lower than thatfound under laboratory conditions.This can be explained somewhat because only whiting between 8 and 16inches (20.3 and 40.6 cm) were usedin the laboratory tests. With fish oflarge size ranges, the yield is appreciably decreased for the machine was setfor maximum recovery in the 10- tol4-inch (25.4- to 35-cm) range.
Even if whiting are to be sold as aheadless and dressed item, the 46 percent yield from the prototype machineas compared with a 50 percent yieldfrom the conventional headless anddressed operation should be no deterrent, especially as the quality of theformer is better than that of the latter.
The improved appearance of thefish with all of the viscera removedand the potential shelf life extensionof the product from the prototypemachine should be able to commanda higher price than that of conventional headless whiting. Most whitingprocessed in the conventional waycontain a small amount of viscera.Therefore, they cannot be labelled asheadless and dressed fish but must belabelled as headless whiting.
However, in a plant under U.S.Department of Commerce inspection,the fish from the prototype machinecould carry the U.S. Grade A stampbecause they would easily conform to
the headless, dressed whiting standard. Where the whiting are to be putthrough a meat/bone separator or areto be further processed, the completeremoval of viscera and black belly lining is essential.
Cleaning Efficiency
The number of fully cleaned whiting, requiring no followup hand clean-
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ing, obtained from the machine wastaken as a measure of its effectivenessunder commercial conditions. Approximately 30 percent of the whitingwere found to fit this category. About65 percent had only a very small pieceof black belly lining on them andabout 5 percent had both pieces ofviscera and black belly lining. An inspector at the end of the cleaningmachine should be able to remove bitsof black belly lining with a plasticbrush or by handpicking so that about95 percent of the whiting would becom pletely clean. The remaining 5percent could be recycled or handcleaned at the end of the run.
Although most of the black bellylining was removed by the two cleaning wheels and serrated roller at theend of the machine, it was observedthat the 6-inch (l5.2-cm) diametercleaning wheels would only cleansmall fish whose belly flaps did notexceed 2.5 inches (6.35 em) in size.The shaft on the wheel restrained thebelly flap from being in full contactwith the cleaning wheel. Since mostof the whiting in the commercial trialwere quite large, they tended to havebelly flaps longer than those thatcould be cleaned by the 6-inch (15.2em) wheel presently on the machine.This is believed to account for thesmall amount of black belly liningremaining on the large whiting.
Problems Encountered
In addition to the time lost forwashing the machine during the run,several other problems were encountered. One of the major downtimeproblems was the binding of the shaftsin certain sections of the machine.These shafts did not have sealed bearings, and fish juice which seeped intothem tended to increase resistanceforces until the shafts eventuallystopped turning. Prior to each run, theywere freed and oiled; but during therun, the fish juice would cause someshafts to stick and/or to stop turning.
Several other minor problems wereencountered during the commercialruns. One of these was the turning ofthe fish head on the cleated conveyorprior to its being removed. Since onlythe body of the fish is supported by
the conveyor, the head resting againsta stationary flat plastic guide is retarded slightly under the frictionalforce as it is dragged along to theheading blade. This causes the part ofthe fish that meets the rotating heading blade to be cut at an angle. If thehead were also conveyed on its ownsystem, the cut could be made perpendicular to the axis of the fish formaximum yield.
Until recently, most conventionalheading machines had this inefficientaspect, but the trend is now leaningtoward the multiple metal pocket conveyor where the fish are secured inposition while the head is being removed and other cuts are being made.This operation, which takes place atthe operating speed of the machine,measures the head of the fish as itcomes down the conveyor and clampsit in position to sever it at the correctangle for maximum yield. We haveconcluded that a higher and significantefficiency is possible and should be attained.
Another problem was the wetting ofthe electronic circuit boards, especially during clean-up operations. Thecircuitry had been mounted in waterproof housings and all connectionshad been made waterproof with rubber gaskets and other seals. However,during the moving of the machinefrom Gloucester to East Boston,Mass., the cables for power, water,and air had to be disconnected and reconnected at their destination. Subsequently, some of the connectionsleaked and, as a result, the main electronic circuit board broke down due tothe water and had to be replaced. As atemporary measure, clear plastic covers were used to protect the electronicgear which will be redesigned so thatthe controls and other susceptibleequipment would be completely protected.
During operation of the machine, alarge amount of fish waste collectedunder it. This is acceptable in smalloperations; but in a large continuousoperation, gurry conveyors should beinstalled. Most large fish processorsalready have these conveyors available; therefore, no design work isneeded, only installation.
Marine Fisheries Review
Table 1.-Annual cost 01 processing whiting in theprototype machine vs. a manual operation'.
1Based on the need for 11 cutters for manual operation forthe same production of fish cleaned using the machineand 4 people.
commercial whiting processor topurchase a machine similar to the prototype machine described in this article.
After careful consideration of thecost and complexity of the modifications needed to increase the speed andefficiency of the prototype headingand cleaning machine, we recommendbuilding a completely new secondgeneration heading and cleaning unitrather than modifying the existing prototype machine. The second generation model would have improved features to: I) Increase throughput offish; 2) lower number of rejects requiring further handling; 3) reducedown-time (for any reason); and 4)maximize effectiveness of operatingcomponents in the production line.
The new line of machines would bebuilt around the successful engineering principles found in the prototypemachine but would have a muchlarger throughput. In the smallerplants, one machine would besufficient to handle their productionwhile in the larger plants, as many asthree machines would be installed,depending upon the amount of fish tobe processed.
The proposed high capacity fishprocessing line is shown in Figure 2.Each unit would have a throughput ofabout 200 fish/minute; and if all threem'lchines were operating at full capac-
Products From Whiting Machine
Although headed and cleaned whiting can be used as the starting material for a wide variety of fishery products, especially extrudable minceditems (Mendelsohn, 1974a), only twotypes of whiting products-a frozenreverse-butterfly or pan-ready itemand a frozen minced block-wereprepared. The variety of product typeswas limited by the equipment that wasavailable in the participating plant.
The pan-ready product needs nofurther processing and can be sold asa small consumer or large institutionalpack. At the processing plant, theclean whiting were packed in layers(head to tail), separated by plasticsheets, in 10-pound waxed boxes andfrozen in a plate freezer. After freezing, the boxes were placed into a master carton and the carton kept at-10°F (-23°C). National MarineFisheries Service personnel and oneindustry member examined the panready product made from very freshwhiting and judged it highly acceptable. The pan-ready product madefrom 5-6 day old whiting was judgedas somewhat less acceptable due to itsslightly "fishy" odor.
The frozen minced whiting blockswere made by putting the cleaned,headless whiting through the meat/bone separator. The minced productwas then put into 18.5-pound waxedcartons and frozen in a plate freezer.After freezing, four blocks wereplaced inside a plastic bag and into amaster carton. The cartons were thenplaced into a freezer held at -1O~(-23°C).
To determine the acceptance ofthese blocks, they were cut into fishsticks and battered and breaded. Theresults of an organoleptic evaluationof the sticks made from fresh whitingby laboratory personnel showed thatthey were highly acceptable. They received an overall score of 7.3 (good tovery good).4 Sticks made from thepenned whiting (5-6 days old) using
4 Based on a scale of 9 to I where: 9 = excellent, 8=verygood,7=good,6 =fair,5 = borderline,4 = slightly poor, 3 = poor, 2 = very poor, andI = inedible (Mendelsohn, 1974b).
the same processing conditions wererated 6.4 (fair to good).
The largest quality differences between the penned whiting and day-boatwhiting were recorded in their appearance and flavor. In the sticks madefrom the older fish, more black spotsappeared because of their softer skinwhich tended to squeeze through theholes in the meat/bone separator drumand be collected with the edible portion.
Recommendations andConclusions
The result of our tests indicated thatthe prototype whiting processingmachine performed largely as expected. However, the commercial operation uncovered the need to furthermodify it and to add accessoryequipment in order to attain itsmaximum production potential.
Even though the throughput of theprototype machine is too low to meetthe demand in the larger processingplants, there is still a sizeableeconomic advantage in using amachine of this type. Based on current labor practices in the Gloucesterarea, where fish processors pay about$7.70/hour (including fringe benefits)for general help and $8.65/hour forcutters and semiskilled workers, wehave calculated the annual cost forprocessing a similar volume of fishusing the prototype fish heading andcleaning machine and compared itwith the cost of heading and cleaningthe fish manually. We assumed thatthe cost of building the prototypemachine to be $40,000. This estimateis based on our experience with otherfish processing machines. Interestrates were calculated on 12 percentper annum, and the machine wasamortized over a period of 5 years.Utility costs were calculated from actual commercial water and electricitybills. The total costs are itemized andtabulated in Table I.
As shown in Table I, using the prototype machine with its limited capacity could save a fish processor over$115,000 on a yearly basis. Coupledwith a more consistently cleaned product of higher qual ity, we concludethat it would be worthwhile for a
Ilem
Prototype machineMachine (amortized over 5 yr)
Principal and interestMaintenanceLabor
3 General help @$16.016/yr1 Semiskilled help
ElectricityWater
Total
Manual operationLabor
11 Semiskilled help (cutters)@,' $17,992/yr
Waler
Total
Difference
COSI
$ 10,6905,000
48,04817,992
903373
$ 83.006
$197,912186
$198,098
$115.092
January 1980 41
WHOLE FISH
TATION
OR
\ING and CLEANINGHINE FOR SMALLFISH (601-1001
)
~HOPPERSCALINGMACHINE
~LONGITUDINAL
LONGITUDINALADJUSTABLE IORIENTOR
I GRADER ORIENTOR
+!LONGITUDINAL
I I CONVEYONVEYOR
) ORIENTOR
CONVEYOR-HEAD
NING MACRGE
') SLITTING BLADE
CLEANING WHEELS \/ ;)\ .... HEADING S°35 ::0
C
HEADING and CLEAMACHINE FOR LA
FISH (14"-18'
HEADING and CLEANING MACHINE FORMEDIUM FISH (10"-14") OR ADJUSTABLE
FOR RANGES OF FISH BETWEEN 6"and 18"
Figure 2. -Proposed high capacity processing line to head and clean 6-18 inch(15.2-45.7 COl) fish.
ity, the line would be able to handle600 fish/minute varying within a sizerange from 6 to 18 inches (15.2-45.7em) in length.
As shown in Figure 2, the highcapacity processing line would contain the following pieces of equipment:
I) An in-line rotary scalingmachine to scale all the fish whilethey are still in the round. In the conventional processing of whiting, thescaling operation is done by a rotaryscaler in a later part of the processingsequence. We are suggesting to do itas a first step when the fish are in the
round to eliminate immediately theproblems caused by the scales.
2) An adjustable size graderwhich will separate the fish into threesize ranges, 6-10 inches (15.2-25.4em), 10-14 inches (25.4-35.6 em),and 14-18 inches (35.6-45.7 em).
3) A reservoir to hold each size of
42 Marine Fisheries Review
fish until they are ready to be conveyed into a machine that: a) Orientsthe fish longitudinally, and b) orientsthe fish vertically.
4) A machine to position the fishto be loaded automatically four at atime onto the infeed conveyor.
5) A conveyor to move the fishinto an automatic device which measures the length of the head and setsthe cut-off knife to remove the headwith a minimum loss of fish flesh.
6) An offloading device thattransfers the fish to the processingconveyor where the fish is held in position between the carrier belts of thecleaning machine.
7) Semiautomatic air pressurecontrols to change the pressure adjustments to regulate: a) The depth ofthe rotary slitting blade used to openthe fish's belly; b) the lateral pressureon the belts that hold the inner portionof the fish against the cleaningwheels; c) the vertical downwardpressure on the hold-down rolls whichkeep the fish tight over the cleaningwheels that remove the viscera alongthe backbone. The size of the fishpassing through the machine determines the pressure that each pressurecontrol should apply to do the cleaning job without losing excessive fishflesh. Sorting the fish into three sizecategories and running one size category at a time makes it possible to adjust one set of regulators at a time tohandle the one size category of fish toits best advantage. In a small plantwith only one cleaning machine, eachset of regulators would be preset andcontrolled by a selector switch tohandle a single size range of fish. Thesize of the range would be no greaterthan 4 inches (10.2 cm) in length. Bypressing the preselector button, thecontrol system that had been in command for one size category would beshut off, and the controls for the sizecategory to be run would be cut in.The time for switching controls willbe in the order of 5 seconds. In the
January 1980
larger processing plants where threeheading and cleaning machines areneeded to handle their throughput, thecontrols on each machine would bepreset for one size range of fish -alsonot to exceed 4 inches (10.2 cm) inthe variability of length. Althougheach machine would have the capability of manually switching from onesize range to another, it would be unnecessary when using the threemachines. This system increases theeffectiveness of the machines bymatching the size range of the fish tothe pressure range of the controls.One range of pressure settings doesnot work for a full size range of fish.
8) Cleaning wheels of increaseddiameter (from 6 inches (15.2 cm) to12 inches (30.4 cm)) in addition to athird cleaning wheel. This changeshould greatly improve the quality ofcleaning the belly cavity, especially inregard to the black belly lining in thelarger fish. With a l2-inch (30A-cm)cleaning wheel, the carrier bel t can be7 inches (17.8 cm) wide to hold theentire belly flap against the side of thewheel with optimum pressure to remove all of the black peritoneum.With three 12-inch (30.4-cm) cleaningwheels, the extension conveyor at theend of the present machine equippedwith a conical skinning wheel to cleanup the tips of the belly flaps will beunnecessary. This system should giveadequate internal cleaning so that thecarrier belts can release the fish directly onto the inspection belt whichthen drops the cleaned fish onto aconveyor for further processing.
9) Carriers with high belt speedsand a transfer system for conveying12,000 fish/hour.
10) A large and efficient waste disposal system. In the prototypemachine, the gurry disposal systemwas overtaxed necessitating shutdowns to clean the gurry ducts andareas where buildups occurred. A solution to this problem is to install oneor more high pressure fan-jets at each
station where fish parts and gurry accumulate. The hoses to the fan-jetswould be secured to a rack connectedto an air or hydraulic cylinder whichwould operate on time intervals of 15minutes. At the preset time cycle, thehoses would make one traverse andthen return to a starting position. Fishparts which had accumulated duringthe previous minutes would bewashed down the gurry ducts to conveyors for quick removal, thus making it a smooth continuous operationand eliminating the need to stop themachine for cleaning.
A system of machines as describedabove is not only commercially feasible but is necessary for processinglarge quantities of fish between 6 and18 inches (15.2 and 45.7 cm) inlength to keep production costs competitive with costs in other food industries. Also, since more and more emphasis is being placed on quality, theproposed processing line would produce consistently high quality seafoodproducts.
Acknowledgments
This work was supported in part bythe New England Fisheries SteeringCommittee under contract with Channel Fish Co., East Boston, Mass. Theauthors also gratefully acknowlege thehelp given by the personnel of Channel Fish Co. during the commercialtesting of the prototype machine.
Literature CitedAnonymous. 1977. New England Fisheries De
velopment Program Report of Progress 1977.New England Fisheries Steering Committee,New Bedford, Mass., 20 p.
Mendelsohn, 1. M. 1974a. Minced fish in a newform. Mar. Fish. Rev. 36(8):34-36.
___. 1974b. A study: Expanded processing techniques, production costs and marketsurvey of underutiIi zed fish species. U.S. Dep.Commer., Econ. Dev. Admin., Tech. Assist.Proj. 01-6-09131-2, 51 p.
___, T. J. Connors, and J. G. Callan.1977. A machine for heading and evisceratingsmall fish. Mar. Fish. Rev. 39(2):11-18.
Ryan, J. J. 1978. Preparation offish fillet blocks.Mar. Fish. Rev. 40(1):5-12.
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