High Quality Frozen Seafoods:·The Need and the Potential

in the United States

J. T R. NICKERSON and L. J RONSIVALLI

Introduction

The passage of the Fishery Conserv­ation and Management Act of 1976,which brings relatively rich fishingareas within the newly established 200­mile jurisdictional boundary off U.S.coasts, makes possible larger catchesfor U.S. fishing vessels. And, since theoverall harvesting pressure will bemarkedly reduced due to reductionin foreign fishing, replenishment ofimportant species such as haddock willeventually result in the availability ofeven more fish to catch. Thus, there isthe potential for the United States toonce again become one of the topfishing nations of the world-adesirable position for this country.

Increased landings would reduce thisnation's heavy dependence on imports,making it less vulnerable to thevagaries of international competitionfor edible goods. Increased landingswould also tend to improve our posi­tion in international trade, especially ifwe could catch enough fish to not onlysatisfy the bulk of our demand but toincrease our exports significantly. This

J. T. R. Nickerson and L. J. Ronsivalli are withthe Gloucester Laboratory, Northeast Fisher­Ies Center, National Marine Fisheries ServiceNOAA, Emerson Avenue. Gloucester MA01930. '

April 1979

would, of course, be associated with anincrease in processing effort andcorresponding increases in ancillarybusiness activities.

Even though it may be too soon toexpect any sizeable increase in the fishstocks, evidence of an impending sea­food bonanza is reflected in an un­usual increase in harvesting capacityand a burgeoning interest in the vari­ous elements of the seafood industry.

The potential for increased seafoodharvests goes beyond the simple eco­nomics of increasing the domestic out­put. It could account for a significantincrease in the per capita consumptionof seafoods in this country (per capitaconsumption equals the total numberof pounds of seafoods consumed in Iyear divided by the total population).In the United States this is about 12.5pounds, and it has not changed muchin decades, despite the fact that fishoffer unique nutritional and perhapstherapeutic advantages as proteinfoods. Thus, increased domesticlandings might result in a higher percapita consumption which would ben­efit the health of consumers as some ofthe meat in the diet became replacedwith fish and fish products, especiallythose that are low in fat.

To get some perspective of the quan­tity of the increased landings that ispossible, it should be noted that foreign

vessels harvested an estimated 3.7 bil­lion pounds of fish during 1977 in theU.S. fishery conservation zone (with­in the 200-mile limit). While it is notpractical to anticipate that the UnitedStates could actually increase its land­ings by that much, certainly there is noreason why U.S. fishermen could notgear up to catch the bulk of thatamount.

In the United States, fish are largelyconsumed as fresh, frozen, canned, andcured. Should the per capita consump­tion increase, it is believed that the bulkof the added consumption would be inthe form of frozen products, eventhough it is expected that there wouldbe a sizeable increase in the consump­tion of fresh products. Currently thereare indications of increased sales offresh fish in various parts of the coun­try, especially where attempts are madeto control the quality of the products.While the growth is largely in coastalareas, the use of air transportation hasmade possible the delivery of high­quality fresh seafoods to inland areas.Indications are that quality is so impor­tant to consumers that they are willingto pay the added costs that are incurredto maintain quality. The added costsinclude those for inspection, prepack­aging, proper refrigeration, and specialhandling. As a matter of fact, it hasbeen speculated that the outstanding

Prepackaged U.S. Grade A fish fillets.

reason for the low per capita consump­tion of fish in the United States is theunreliability of its quality at point ofsale. A recently completed 2-year studyby the National Marine Fisheries Ser­vice demonstrated that when qualitywas assured to be U.S. Grade A atpoint of sale, there was a measurableincrease in sales, up to 20 percent(Ronsivalli et aI., 1978). However, thedistribution of fresh fish is associatedwith losses due to spoilage, limiteddistribution due to the short shelf life ofthe product, mishandling due tolaxity, large fluctuation in price due tothe sharp shifts in the supply-to­demand ratio, and unreliability ofsupply due to the variety of reasonswhy fish are sometimes not landed insufficient amounts. (Many vesselseither do not go to sea or, if at sea,cannot harvest fish effectively duringstormy weather, adequate catches arenot always made, malfunction of gear,accident, etc.)

The logical disposition of additionallandings would be to preserve them byfreezing as fillets, fillet blocks, wholefish, steaks, and prepared products. In

2

the first place, preserving fish byfreezing keeps them at near initialquality when they are properly han­dled, packaged, and stored. Alsofrozen products can be held for quitelong periods (more that I year). Thus,large landings could be frozen andstored. (Otherwise, in many cases largelandings currently command a rela­tively low price per pound. On the otherhand, prices make a sharp rise whenlandings are low.) By freezing fishduring times of glut, the supply duringlean times could be assured, and thiswould result in stabilization of both theprices at retail and the reliability ofsupply all year round for the consumer,the institutional user, and the proces­sor. When fish are properly frozen andproperly handled, the long storage lifethat results permits distribution any­where in the world, provided that thetransportation vehicle is capable ofproviding the necessary refrigerationcapacity. The economic potential forhandling fish in the frozen form isevidenced by the fact that fast-foodchains use only frozen fish for their fishsandwiches, the high quality of which is

indicated by the strong sales growth ofthis commodity. Also, the notion thatfrozen fish is not as good as fresh fish inquality is not supported when onecompares the quality of fish in the fast­food chain sandwiches with the qualityof fresh fish. The facts are that thefrozen fish that become fish sandwich­es in fast-food chains are of high initialquality, and are properly frozen andhandled, whereas frozen fish that areeventually sold in the retail cases ofsupermarkets are of variable qualityinitially and maybe frozen and handledin less than satisfactory fashion. Thiscan result in products that may berancid, tough, dehydrated, and gener­ally unacceptable.

What is Needed

For more than a decade the Con­sumers Union I and other consumergroups have published articles con­demning the quality offishery productsthat are available to the consumer. Inone article (Anonymous, 1961), thereligious connotation of fish as a pen­nance food is attributed to the image ofpoor quality with which it has longbeen associated. A recent study (Ron­sivalli et aI., 1978) has demonstratedbeyond doubt the customer satisfac­tion and demand gained by controllingthe quality of the product. Whilefreezing is theoretically the preferredmethod for preserving fish, certainchanges in attitude and procedures willhave to occur in the way fish are har­vested, processed, packaged, trans­ported, stored, and displayed at retailif we are to produce high quality frozenfish.

Temperature Control

The shelf life of fresh fish at 32° F isabout 2 weeks. Its quality remains atGrade A for about I week. Both theshelf life and the time during which theproduct remains at Grade A are short­ened as the holding temperature isincreased. Thus, since much ofthe U.S.catch is landed unfrozen, it can be seenthat the length of time and the tem-

I Reference to commercial firms or groups doesnot imply endorsement by the ational MarineFisheries Service, NOAA.

Marine Fisheries Review

Preparing U.S. Grade A fish fillets for shipment.

perature at which fish are keptaboard the fishing vessel and.else­where. until they are frozen, willdetermine the quality of the productat time of freezing. Ab-oard thefishi ng vessel, fish will ha ve to be welliced (Dassow, 1976), preferably inboxes, or they may be held in chilledseawater (Hulme and :lBaker, 1977),and, at that, they should 'not be held forlonger than 2-3 days. It cim be seenfrom this that whether 'v;essels arebringing in fish that are to be 'handledas fresh in the distribution chain or asfrozen, it appears that they, cannotmake trips that are longer tnan 2-3days, unless (for fish to be s d asfrozen) they have the capacity to freezeall fish that might conceivably have t'@spend more than 2-3 days before they'can be processed on land. There is noalternative to these guidelines, whichwill add to the cost, but the extra costinvolved in' following them will bereturnee in enhanced image, less wasteof resource through spoilage, satisfiedconsumers· who' are willing to absorbthe extra cost (R'onsivailt et aI., 1978),etc.

Whether increased landings arefrozen at sea or (as appears most likelyfor most U.S. vessels) on land, theproduct must be frozen as soon aspossible. It must be packaged so as notto lose moisture nor to be exposed tooxygen, and throughout its distribu­tion and storage, its temperatureshould not be allowed to exceed 00 F.

Warehouse and Freezing Capacities

To hold frozen products for varyinglengths of time, considerable ware­house space will be needed. At present,the processors of marine products donot have capacity to freeze and storelarge quantities of fish and shellfish.There should, therefore. be a consider­able investment in both-whateverequipment may be necessary for thefreezing of predictable increasedamounts of marine products as well asfor the storage of these products atsuitable low temperatures. This shouldenable processors to take care of theirneeds for further processing as requir­ed in the production of such foods asfish sticks and fish portions and also

April 1979

provide for increased retail sales offrozen fish fillets.

Packaging

The packaging of frozen marine pro­ducts under current practices is almosttotally inadequate. Almost all pack­ages used for these foods offer littlebarrier to moisture loss or to the entryof oxygen. Thus, dehydration occurs,accelerating both rancidification andtoughening (denaturation of proteins),and, of course, since these packagesallow the diffusion of oxygen, oxida­tion, which causes rancidification, isfurther accelerated. Another deficiencyof packaging for products such asbreaded shrimp is the space within thepackage that is not occupied by theproduct. This leads to dehydration ofthe food, reduced net weight, cavity-iceformation, and deterioration of thequality of the product during frozenstorage.

Many packaging materials, includ­ing polyesters, polyvinylidene chloride,and aluminum laminates are presently

available for frozen foods which willprevent dehydration of the food andthe diffusion of oxygen, hence prevent­ing oxidation and rancidification.They also provide for packing the foodunder a vacuum, hence eliminatingempty space within the package andthus the formation of cavity ice. Thistype of packaging is more expensivethan the inadequate ones which aremostly in use today, but, consideringthe present average cost of fish andshellfish to the consumer, it should beno deterrent to add the price of adequatepackaging to seafoods. This is espe­cially the case since, in the long run, theconsumer would benefit by receiving afood of much better quality. At pres­ent, it is very difficult to buy salmonand mackerel, during winter months,which are not rancid. If packaged prop­erly there is no reason that it should notbe possible to obtain good quality salm­on steaks and mackerel fillets at anytime of year. This is especially the casewith these fish since they are not sub­ject to toughening or to denaturationof their proteins. It should be noted

3

r

Figure I.-Cross section of an open-shelf freezer display.

WARM AIR I COLD AIRI I I

\ L '---.J,+---.J,I---+.J,-~

~ FF\ ,-,lrr=-j=

for storage. In general, transportationprocedures for these products have notbeen and are not good. Too oftentrucks with no refrigeration are usedfor moving these products over shortor even somewhat longer distancesand, for long hauls, inadequate refrig­eration is used and some truck drivershave been known to sometimes shut offthe refrigeration system even when itwas available. Thus, oftentimes thealready frozen load is depended uponto provide the refrigeration within thecarrier. It has been stated that "frozenfoods have a memory," which meansthat any time they have been held, evenfor short periods, above suitably lowtemperatures, and especially above0° F, the produce undergoes somedeterioration and that this deteriora-

tion will result in a shortening of thefrozen shelf life of the food. There isno reason why a temperature record­er could not be placed in trucks trans­porting frozen foods in order to checkthat the transporters of these foodsmaintain temperatures of O°F orbelow in all parts of the load duringshipment. This has been done in someinstances. Since, except for fast-foodchains, most retailers of frozen foodswill not accept the responsibility ofdetermining whether adequately lowtemperatures are maintained duringthe shipment of frozen products, itwould appear to be up to the produc­er to require strict transportingspecifications and to use only thosetransporters who follow the requiredhandling procedures.

Handling at Retail

In all probability frozen foods de­teriorate to the greatest extent at theretail outlet because of inadequatespeed of handling upon arrival, dis­play at temperatures which are notlow enough, and neglect of effectiverotation of product, i.e., the first itemto be offered for sale should be thefirst item sold. When a carrier arrivesat its destination, the driver is eager tounload and move on. However, thisshould only be done when there isenough help available to promptlymove the product to frozen storage.This policy would prevent the storageof frozen foods on outside platformsor inside rooms where the ambienttemperatures may be quite high. Stor­age rooms at retail stores should beheld at O°F or below. In Massachusetts(and possibly other states), it is illegalto hold frozen foods at temperatureshigher than O°F. This law is importantfor insuring the maintenance of goodquality and avoiding any possibility ofthe development of microbial toxins.Accordingly, a similar law, strictly en­forced in all states, would greatly en­hance the quality of frozen fish and fishproducts.

There are three methods of display­ing frozen foods at retail, and two ofthese are inadequate as well as waste­ful. Probably the worst of these is theopen-shelf unit (Fig. 1). This type of

Product in front undergoesrelatively largefluctuations in temperature.Product in back and bottomof each shelf may remain inbox for long periods unlessrotated.

BACK

r-,I rr=-'r=-

r-rrIIIIII

r-r-r­r-r-r-iIIII

IIIIr--r-ilIIII

FRONT

that even low-fat fish such as cod aresubject to the development of rancidityduring frozen storage.

The adequate packaging of marinefoods is the responsibility of the pack­er, and until there is a change of atti­tude in this respect, there can be littleimprovement in the quality of frozenmarine products.

After packing and freezing, fish andshellfish should be held at 0° F or be­low. Generally the packers of suchfoods have done a good job in thisrespect.

Transportation

Frozen foods must be transportedfrom the point where they were pro­duced to. the point where they will beretailed or consumed or to a warehouse

4 Marine Fisheries Review

BACK

Product above loadline and may undergopartial thawing

LOAD LINE

Product at this levelis at coldest temperaturebut may not be picked upby consumer unlessrotated

CIIIIIIIIIII

IIIIr--Il r

I-II~

IIIIIIIIIIII

IIIIIIIIIllrIIII,r--,I

-

GLASSDOOR --.

FRONT

Exchange of airwith outside

I ~~~ ~~t-I"""-- Product at this levelI I I I is at higher temperature~~~~~ and subject to

I I I I I temperature fluctuation

~IIII1;I~~t,

I I I ICOLD AIR

Figure 2.-Cross section of open-top freezer.

freezer display case also wastes energysince much of the refrigerated air es­capes. It also wastes the products thateventually spoil in it. Generally, it is notoperated properly, resulting in hightemperatures around the product and,in some cases, even defrosting some ofthe food, and it does not provide for thehandling of the food on a "first in,first out" basis.

The open top frozen food displaycase (Fig. 2) probably provides bettertemperature for frozen foods than theopen-shelf type of frozen food cabinetsince cold air is heavier than warm airand tends not to leave the box, but inthis instance the frozen product may bepiled above the load line, resulting inexposure to high temperatures. Again,there is a defrosting problem with suchdisplay cases, and no provision is madefor moving the food on a "first in, firstout" basis. Some of these cabinets havesliding glass covers, but these are oftenleft open by customers.

Probably the best display freezer incurrent use for frozen foods is the en­closed shelf-type case having glass­paneled doors (Fig. 3). This type offreezer probably provides fairly goodtemperatures for frozen foods eventhough individuals sometimes open thedoors and look for what they wish topurchase for several minutes at a time,causing cold air to escape. But even inthis type of case there is no provisionfor handling the product on a "first in,first out" basis. Also, as with the othertwo types of display cases, both theirdesign and their mode of operationmake it impossible to maintain the pro­ducts at a uniform and relatively con­stant temperature. Thus, the product isexposed to a broad range of tempera­tures, depending on its location withinthe box, and to a large fluctuation oftemperatures because of the designwhich has either a large open side or alarge side that is open frequently. Botha broad range of temperatures andfluctuating temperatures contribute todeterioration of quality. These units

Figure 3.-Cross section of enclosed upright freezer case.

•April 1979 5

THERMOPANEVIEW GLASS LOADING

DOOR

DISPENSINGKNOB

PROCUREMENTPORT

Figure 4.-Conceptual design of frozen seafood dis­penser.

U.S. Grade A fish fillets at the supermarket.

6

are also plagued with frequent frostingdue to the continuing condensing ofmoisture present in the ambient airwhich enters the box.

Consideration of these problems hasled to the concept of a design whichemploys principles used in vendingmachines (Fig. 4). Vending machinesare entirely closed, except for smallopenings that permit the discharge ofitems therefrom, in single units. Thisdesign radically minimizes the ex­change of cold air in the machine withthe warm ambient air. It further per­mits an opportunity to effectively in­sulate the contents from the entry ofambient heat. A thermopane windowcan be used to permit the customer toview the product.

Vending machines also employ a un­it conveyor system that automaticallydispenses the first unit loaded into themachine. Thus, for the first time the"first in, first out" principle is relative­ly assured and the undesirable proba­bility that any of the product mightremain in storage for excessively longperiods is virtually eliminated. It elim­inates problems created by pull-datesdue to the customer's selection of thoseunits that have the longest shelf liferemaining. This type of freezer case hasother advantages which include the vir­tual elimination of frost accumulationwithin it and on elements of its refriger­ation system because of the inability ofmoisture-laden ambient air to enter it.Also, since the product will be packag­ed in gas-impermeable containers,there can be no migration of moisturefrom the product to any part of thedisplay case.

As with any innovative change in aprocess, disadvantages of such a dis­play case may emerge when it is testedunder commercial conditions. Onepossibility is that a customer may dis­pense a package, not like it for somereason, dispense a second or even athird one before being satisfied, leavingthe first or second package at ambienttemperature, having no way to return itto the machine's conveyor system. Thisprobability can be lowered or perhapseliminated by insuring uniform apear­ance and weight among packages. Nev­ertheless, the advantages to be derived,

Marine Fisheries Review

FILLETS'

Package'

'Inspect for quality-use onlyU.S. Grade A-and during processing

'Use gas impermeable and water­vapor impermeable containers

1LABORATORY'

i~ ~0° F -10°F -20°F

~CONVENTIONALDISPLAY CASESheld at OaF

RETAILMARKETS'

I

EXPERIMENTAL'DISPLAY CASEheld at O°F

Figure 6.-- Expenmental design to test recommended procedures.

'USDC inspected, only U.S. Grade A product to be used

'Package to be specified by collaboratingpackaging engineer

'Marketing and economic analysis bycollaborating Sea Grant Universities

'Experimental display case to be built bycollaborating manufacturer Energy savingsand quality protection characteristics ofprototype to be compared with those ofconventional cases'Storage study in laboratory to determineeffect of storage temperature on quality,shelf life, and economics of frozen storedfillets

FISH' (2 days or less out of waterand held at ice temperature)

tFILLET'

tPackage'

~Freeze to 0° F

1

RETAILER' orINSTITUTIONALUSER must holdat 0° F or loweruntil used

DISTRIBUTOR'SWAREHOUSE heldat 0° F or lower

Ship only by vehicles that canmaintain temperature at 0° For lower

i-~

'Retailer and other users shouldbe checked for compliance withspecified guidelines on handling

Figure 5. -A handling sequence toinsure the quality offrozen fish fil­lets at U. S. Grade A at time of use.

•Freeze to 0° F

~Store at 0° F or lower

~

FISH' ( 2 days or less out of thewater held at ice temperature)

•

especially in conserving energy andpreventing spoilage, are expected tooutweigh the disadvantages.

Recommended Handling Procedure

Some of the recommendations madeherein derive simply from the applica­tion of a common sense attitude thatshould be applied in the handling of allfoods. Some of the recommendationsmay meet with some reluctance, espec­ially where expensive packaging andthe use of more refrigeration implieshigher costs. However, it is anticipatedthat the added cost will not be very highand it has already been demonstrated

that consumers are prepared to pay theslightly higher price in return for high­quality products. A summary of theserecommendations for handling fishfillets is shown in the flow diagram inFigure 5.

An experiment could be designed todemonstrate the ability to maintain thehigh quality of fish fillets and the tech­nical feasibility of the recommenda­tions. The economics of the recom­mended procedures can be measured,and these would include a measure ofefficacies of specified packaging andthe frozen fillet storage/ dispenser caseshown in Figure 4. A flow diagram of

the experimental procedure is shown inFigure 6.

Literature Cited

Anonymous. 1961 Frozen fried fish sticks.Cons. Rep. 26:80-S.1.

Dassow, J. A. 1976. Handling fresh fish, InM. E. Stansby (editor), Industrial fisherytechnology, p. 269-282. Raben E. KriegerPub!. Co, Huntington. ;'II.Y.

Hulme. S. E. and I). W Baker. 1977 Chilledseawater system for bulk holding sea herr­ing. Mar Fish Rn .19(3):4-9.

Ronsivalli, l.. J., C. Gorga, J D. Kaylor, andJ. H. Carver. 1978. A concept for assuringthe quality of seafoods to consumers. MarFish. Rev 40( I): 1-4.

April 1979 7