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18.1
',%48)6
*-7,)6=463(9'87
FRESH FISHERY PRODUCTS .............................................. 18.1
Care Aboard Jessels ............................................................... 18.1
Shore Plant Procedure and Marketing ................................... 18.3
Packaging Fresh Fish ............................................................. 18.3
Fresh Fish Storage .................................................................. 18.4
FROZEN FISHERY PRODUCTS ........................................... 18.4
Packaging ................................................................................ 18.4
Free:ing Methods .................................................................... 18.5
Storage of Fro:en Fish ............................................................ 18.7
Transportation and Marketing ................................................ 18.9
HE major types oI Iish and shellIish harvested Irom North
8American waters and used Ior Iood include the Iollowing:
· GroundIish (haddock, cod, whiting, Ilounder, and ocean perch),
lobster, clams, scallops, snow crab, shrimp, capelin, herring, and
sardines Irom New England and Atlantic Canada
· Oysters, clams, scallops, striped bass, and blue crab Irom the
Middle and South Atlantic
· Shrimp, oysters, red snapper, clams, and mullet Irom along the
GulI Coast
· Lake herring, chubs, carp, buIIaloIish, catIish, yellow perch, and
yellow pike Irom the Mississippi Valley and the Great Lakes
region
· Alaska pollock, PaciIic pollock, tuna, halibut, salmon, PaciIic
cod, various species oI IlatIish, king and snow crab (Chinoecetes
opelio)about 200,000,000 lbs annuallyDungeness crab,
scallops, shrimp, and oysters Irom the PaciIic Coast and Alaska
· CatIish, salmon, trout, oysters, and mussels Irom aquaculture
operations in various parts oI North America
Eish harvested Irom tropical waters are reported to have a sub-
stantially longer shelI liIe than Iish harvested Irom cold waters. This
may be due to the bacterial Ilora naturally associated with the Iish.
The bacteria associated with Iish Irom tropical waters are mainly
gram-negative mesophiles, whereas the bacteria that cause spoilage
oI tropical or other Iish during reIrigerated storage are usually gram-
negative psychrophiles. The time required Ior this bacterial popula-
tion shiIt (Irom mesophiles to psychrophiles) aIter reIrigeration
may account Ior the increased shelI liIe.
The major industrial Iish used Ior Iish meal and oil is menhaden
Irom the Atlantic and GulI coasts. In addition, the parts oI Iish not
used Ior human consumption are oIten used to manuIacture Iish
meal and oil.
Eish meal and oil are the principal components oI the Ieed used
in the aquaculture oI trout and salmon. Meal also is a component oI
the diets oI poultry and pigs. Eish oil is used in margarine, in paints,
and in the tanning industry. It is also being reIined Ior pharmaceu-
tical purposes.
This chapter deals with the preservation and processing oI Iresh
and Irozen Iishery products; the care oI Iresh Iish aboard vessels and
ashore; the technology oI Ireezing Iish; and present commercial
trends in the Ireezing, Irozen storage, and distribution oI seaIood.
See Chapter 26 Ior additional inIormation regarding Iishery
products Ior precooked and prepared Ioods.
HACCP System. Many oI the procedures Ior the control oI
microorganisms are managed by the Hazard Analysis and Critical
Control Point (HACCP) system oI Iood saIety. Each Iood manuIac-
turing site should have a HACCP team to develop and implement
its HACCP plan. See Chapter 11 Ior additional inIormation on san-
itation.
*6)7,*-7,)6=463(9'87
CARE ABOARD VESSELS
AIter Iish are brought aboard a vessel, they must be promptly and
properly cared Ior to ensure maximum quality. Trawl-caught Iish on
the New England and Canadian Atlantic coasts, such as haddock
and cod, are usually eviscerated, washed, and then iced down in the
pens oI the vessel`s hold. The oIIshore Canadian Ileet and the Ileets
oI Iceland, the United Kingdom, and other European countries have
been icing the Iish in boxes Ior optimum quality. Because oI their
small size, other groundIish (e.g., ocean perch, whiting, Ilounder)
are not eviscerated and are not always washed. Instead, they are iced
down directly in the hold oI the vessel.
Crustaceans, such as lobsters and many species oI crabs, are usu-
ally kept alive on the vessel without reIrigeration. Warm-water
shrimp are beheaded, washed, and stored in ice in the hold oI the
vessel; on some vessels, however, the catch is Irozen either in reIrig-
erated brine or in plate Ireezers. Cold-water shrimp are stored whole
in ice or in chilled sea water, or they may be cooked in brine, chilled,
and stored in containers surrounded with ice.
Ereshwater Iish in the Great Lakes and Mississippi River areas
are caught in trap nets, haul seines, or gill nets. They are sorted
according to species into 50 or 100 lb boxes, which are kept on the
deck oI the vessel. In most cases, Iishermen carry ice aboard their
vessels, and the Iish are landed the day they are caught.
Ereshwater Iish in the lakes oI Canada are iced down in the sum-
mertime and stored at collecting stations on the lakes, where they
are picked up by a collecting boat with a reIrigerated hold. Winter-
caught Canadian Ireshwater Iish and Arctic saltwater Iish are usu-
ally weather-Irozen on the ice immediately aIter catching and are
marketed as Irozen Iish.
Line-caught Iish oI the PaciIic Northwest, such as halibut caught
largely by bottom long-line gear and salmon caught by trolling gear,
are eviscerated, washed, and iced in the pens oI the vessel. PaciIic
salmon caught by seines and gill nets Ior cannery use are usually
stored whole Ior several days, either aboard vessels or ashore in
tanks oI seawater reIrigerated to 30°E. A small but signiIicant vol-
ume oI halibut is held similarly in reIrigerated seawater aboard ves-
sels. Tuna caught oIIshore by seiners or clipper vessels are usually
brine-Irozen at sea. However, tuna caught inshore by the smaller
trollers or seiners are oIten iced in the round or reIrigerated with a
brine spray.
Eish raised by aquaculture Iarms are usually harvested and sold
as required by the Iresh Iish market. They are usually shipped in
containers in which they are surrounded by ice.
Icing of Fish
Eish lose quality because oI bacterial or enzymatic activity or
both. Reduction oI storage temperature retards these activities sig-
niIicantly, thus delaying spoilage and autolytic deterioration.
Low temperatures are particularly eIIective in delaying growth oI
psychrophilic bacteria, which are primarily responsible Ior the
spoilage oI nonIatty Iish. The shelI liIe oI species such as haddock
The preparation oI this chapter is assigned to TC 10.9, ReIrigeration Appli-
cation Ior Eoods and Beverages.
Copyright © 2002 ASHRAE
18.2 2002 ASHRAE Refrigeration Handbook
and cod is doubled Ior each 7 to 10°E decrease in storage tempera-
ture within the range oI 60 to 30°E.
To be eIIective, ice must be clean when used aboard a vessel.
Bacteriological tests on ice in the hold oI a Iishing vessel showed
bacterial counts as high as 5 billion per gram oI ice. These results
indicate that (1) chlorinated or potable water should be used in mak-
ing the ice at the ice plant, (2) ice should be stored under sanitary
conditions, and (3) unused ice should be discarded Irom a vessel at
the end oI each trip.
Both Ilake ice and crushed block ice are used aboard Iishing ves-
sels, although Ilake ice is more common because it is cheaper to pro-
duce and easier to handle mechanically.
The amount oI ice used aboard vessels varies with the particular
Iishery and vessel; however, it is essential to provide suIIicient ice
around the Iish to obtain a proper cooling rate (see Eigure 1). A
common ratio oI ice to Iish used in bulk icing on New England
trawlers is one part ice to three parts Iish. Experiments on British
trawlers in boxing Iish at sea with one part ice to two parts Iish
demonstrated improved quality in the landed Iish, and, as ice has
become more plentiIul and less costly relative to the value oI Iish,
the ratio oI ice to Iish continues to increase. Mechanical reIrigera-
tion is employed in some vessels to retard the melting oI ice en
route to the Iishing grounds; however, the hold temperature must
be controlled aIter Iish are taken to allow the ice to melt Ior eIIec-
tive cooling oI the Iish.
Saltwater Icing
Iced Iish storage temperatures must be maintained close to the
Ireezing point oI Iish. To obtain lower ice temperatures, the Ireez-
ing point may be depressed by adding salt to the water Irom which
the ice is made. Adequate amounts oI ice made Irom a 3° solution
oI sodium chloride brine will maintain a storage environment oI
about 30°E. Tests conducted on the storage oI haddock in salt-
water ice aboard a Iishing vessel showed that, under parallel con-
ditions, Iish iced with saltwater ice cooled Iaster and to a lower
temperature than Iish iced with plain ice. However, the saltwater
ice melted Iaster than the plain ice because oI its lower latent heat
and its greater temperature diIIerential. ThereIore, once the salt-
water ice melted, the Iish stored in this ice rose to a higher temper-
ature than those stored in plain ice. Since it is not always possible
to replenish ice on Iish at sea, suIIicient quantities oI saltwater ice
must be used initially to make up Ior its Iaster melting rate.
In making ice Irom water containing a preservative, rapid Ireez-
ing and/or using a stabilizing dispersant is essential to prevent
migration oI the additive to the center oI the ice block. This prob-
lem is not encountered in Ilake ice because Ilake ice machines
Ireeze water rapidly into thin layers oI ice, thus Iixing additives
within the ice Ilakes. Chapter 33 describes the manuIacture oI
Ilake ice in more detail.
Use of Preservatives
In the United States and Canada, the use oI antibiotics in ice or in
dips Ior treatment oI whole or gutted Iish, shucked scallops, and
unpeeled shrimp is prohibited by regulation.
Storage of Fish in Refrigerated Sea Water
ReIrigerated seawater (RSW) is used commercially Ior preserv-
ing Iish. On the PaciIic Coast, substantial quantities oI net-caught
salmon are stored in RSW aboard barges and cannery tenders Ior
delivery to the canneries. Most salmon seiners now use RSW Sys-
tems. It is oIten a condition oI sale. On the East and GulI coasts,
RSW installations on Iishing vessels are used Ior chilling and hold-
ing menhaden and industrial species needed Ior production oI
meal, oil, and pet Iood. On the east and west coasts oI Canada,
RSW installations are used Ior chilling and holding herring and
capelin, which are processed on shore Ior their roe. Other more
limited applications oI RSW include holding PaciIic halibut and
GulI shrimp aboard a vessel; chilling and holding Maine sardines
in shore tanks Ior canning, and short-term holding oI PaciIic
groundIish in shore tanks Ior later Iilleting.
With groundIish and shrimp, RSW works well Ior short-term
storage (2 to 4 days), but it is not suitable Ior longer periods
because oI the excessive salt uptake, accelerated rancidity, poorer
texture, and increased bacterial spoilage that may result. These
problems can be partially overcome by introducing carbon dioxide
(CO

) gas into the RSW; holding in RSW saturated with CO

can
increase the storage liIe oI some species oI Iish by about 1 week.
Additionally, RSW reduces (1) handling that results Irom the bulk
storage oI the Iish and (2) pressure on the Iish as a result oI buoy-
ancy, Iaster cooling, and lower storage temperature.
In many RSW systems, the reIrigeration eIIect is provided by
ammonia Ilowing through external chillers or pipe coils located
within the tanks. Best results have been achieved with external
chillers.
Boxing at Sea
There are many advantages to using containers or boxes instead
oI bulk storage aboard Iishing vessels. Known as boxing at sea, the
use oI containers reduces pressure on the Iish while they are
stowed in a vessel`s hold. Because signiIicant reductions in han-
dling during and aIter unloading are possible, mechanical damage
and product temperature rise may be virtually eliminated and han-
dling costs may be reduced. Eish can be sorted into boxes by size
and species as soon as they are caught. Boxed Iish lend themselves
more readily to mechanized handling, such as machine Iilleting,
because they are generally Iirmer and oI more uniIorm shape; Iillet
yields are generally better than they are with bulk-stored Iish.
Boxing at sea is not generally practiced in the United States,
except by some inshore vessels. The principal problems associated
with converting a Iishing vessel Irom bulk storage to boxed storage
are the increased labor required by the crew Ior handling the boxes,
the reduced hold capacity, and a relatively large investment Ior
boxes. Many Iisheries have diIIiculties working out the logistics
Ior ensuring the prompt return oI properly cleaned boxes to the
vessel. Most oI these problems have been solved in European
Ileets, the Canadian oIIshore Ileet, and South American hake Iish-
ing Ileets. Using nonreturnable containers Ior boxing at sea simpli-
Iies logistics and reduces initial capital outlay; it has proved
justiIiable in some U.S. Iisheries.
Reusable containers Ior boxing at sea are usually made oI plastic.
CareIul icing is necessary to minimize the surIace area oI Iish in
contact with the box. Plastic boxes provide more heat transIer resis-
tance than aluminum boxes in vessels with uninsulated Iish holds
and Ior in-plant storage prior to processing.
All Iish boxes must be equipped with drains, preIerably directed
outside the boxes on the bottom oI a stack.
Fig. 1 Cooling Rate of Properly and Improperly
Iced Haddock
Fig. 1 Cooling Rate of Properly and Improperly
Iced Haddock
Fishery Products 18.3
SHORE PLANT PROCEDURE
AND MARKETING
Proper use oI ice and adherence to good sanitary practices ensure
maintenance oI iced Iish Ireshness during unloading Irom the ves-
sel, at the shore plant, during processing, and throughout the distri-
bution chain. Eish landed in good quality will spoil rapidly iI these
practices are not carried out.
Eish unloaded Irom the vessel are usually graded by the buyer Ior
species, size, and minimum quality speciIication. A price is based in
part on the quality in relation to market requirements. Eish also may
be inspected by local and Iederal regulatory agencies Ior whole-
someness and sanitary condition. Organoleptic criteria are most
important Ior evaluating quality; however, there is a growing accep-
tance, particularly in Canada and some European countries, oI
objective chemical and physical tests as indexes oI quality loss or
spoilage. Organoleptic quality criteria vary somewhat among spe-
cies, but the inIormation in Table 1 can be used as a general guide in
judging the quality oI whole Iish.
In New England and the Canadian Atlantic provinces, ground-
Iish unloaded Irom the vessel may be placed in boxes and trucked to
the shore plant or conveyed directly Irom the hold or deck to the
shore plant. Single- or double-wall insulated boxes are normally
used Ior transporting Iish. Wooden boxes are rarely used because
they are a source oI microbiological contamination. Ice should be
applied generously to each box oI Iish, even iI the period prior to
processing is only a Iew hours. Eish in the plant awaiting processing
Ior longer than a Iew hours should be iced heavily and stored in
insulated containers or in single-wall boxes in a chill room reIriger-
ated to 35°E. II reIrigerated Iacilities are not available, the boxes oI
Iish should be kept in a cool section oI the plant that is clean and san-
itary and has adequate drainage.
Large boxes oI resin-coated plywood or reinIorced Iiberglass
that hold up to 1000 lb oI Iish and ice are used by some plants in
preIerence to icing Iish overnight on the Iloor. These tote boxes are
moved and stacked by IorkliIt, can be used Ior trucking Iish to other
plants, and make better use oI plant Iloor space. Generally, Iish
awaiting processing should not be kept longer than overnight.
Eresh Iish are marketed in diIIerent Iorms: Iillets, whole Iish,
dressed-head on, dressed-headed (head removed), and, in some
instances, steaks. The method oI preparing Iish Ior marketing
depends largely on the species oI Iish and on consumer preIerence.
Eor example, groundIish such as cod and haddock are usually mar-
keted as Iillets or as dressed-headed Iish. Ereshwater Iish such as
catIish and bullheads are usually dressed and skinned; lake trout are
not skinned, but are merely dressed; and lake herring are marketed
in dressed, round, or Iilleted Iorm.
PACKAGING FRESH FISH
Most Iresh Iish is packaged in institutional containers oI 5 to
35 lb capacity at the point oI processing. Polyethylene trays, steel
cans, aluminum trays, plastic-coated solid boxes, wax-impregnated
corrugated Iiberboard boxes, Ioamed polystyrene boxes, and poly-
ethylene bags are used.
Eresh Iish is oIten packaged while it still contains process heat
Irom wash water. In these cases, it is advantageous to use a packag-
ing material that is a good heat conductor. The Iresh Iish industry
makes little use oI controlled prechilling equipment in packaging.
As a result, product temperatures may never reach the optimum
level subsequent to packaging. Traditionally, institutional Iresh Iish
travels packed in wet ice; in this case, it may cool to the proper level
in transit even iI process heat is initially present. However, there is
a trend toward the use oI leaktight shipping containers Ior Iresh Iish
because modern transportation equipment is not designed to handle
wet shipments. Also, some customers want to avoid the cost oI
transporting ice yet demand a product that is uniIormly chilled to 32
to 36°E when it reaches their door. Shippers who use leaktight ship-
ping containers have to upgrade their product temperature control
systems to ensure that the Iish reaches ice temperature prior to pack-
aging. Rapid prechilling systems that result in crust Ireezing can be
applied to some Iresh seaIood products, but this practice must be
used with discretion since partial Ireezing harms quality.
Some general requirements Ior institutional containers that hold
products such as Iillets, steaks, and shucked shellIish are (1) suIIi-
cient rigidity to prevent pressure exerted on the product, even when
containers are stacked or heavily covered with ice; and (2) mea-
sures to prevent ice-melt water Irom contaminating the product.
Some containers have drains permitting the drip associated with
the Iish itselI to run oII. Others are sealed and may be gastight,
which increases shelI liIe. One problem associated with sealed
containers is the emission oI a strong odor when the package is
Iirst opened. Although this odor may be Ioul, it soon dissipates and
has no adverse eIIect on quality. Dressed or whole Iish may be
placed in direct contact with ice in a gastight container.
Leaktight shipping containers are used with nonreIrigerated
transportation systems, such as air Ireight, and consequently require
insulation. Eoamed polystyrene is particularly suited to this appli-
cation. Eor typical air Ireight shipments, the most economical thick-
ness oI insulation is between 1 and 2 in. To maintain product
temperature in transit, shippers use either dry ice, packaged wet ice,
packaged gel reIrigerant, or wet ice with absorbent padding in the
bottom oI the container. Eoamed polystyrene containers may be oI
molded construction or oI the composite type, in which Ioam inserts
and a plastic liner are used with a corrugated Iiberboard box.
At the retail level, Iresh Iish may be handled in two ways.
Stores with service counters display Iish in unpackaged Iorm.
However, markets without service counters sometimes package
Iish prior to displaying Ior sale. Both types oI outlets receive the
product in institutional containers. II the Iish is prepackaged at the
market, high labor and packaging costs may be incurred, and the
temperature oI the product is likely to rise. OIten, relatively warm
Iish is placed in a Ioam tray, wrapped, and displayed in a meat
case, the temperature oI which may be 40°E or more. This drasti-
cally reduces the shelI liIe oI the Iish. Centralized prepackaging at
the point oI initial processing appears to have many important
advantages over the present system. A number oI retail chains have
their suppliers prepackage the product under controlled tempera-
ture and sanitary conditions.
Table 1 Organoleptic Quality Criteria for Fish
Factor Good Quality Poor Quality
Eyes Bright, transparent, oIten protruding Cloudy, oIten pink, sunken
Odor Sweet, Iishy, similar to seaweed Stale, sour, presence oI sulIides, amines
Color Bright, characteristic oI species, sometimes pearlescent
at correct light angles
Eaded, dull
Texture Eirm, may be in rigor, elastic to Iinger pressure SoIt, Ilabby, little resilience, presence oI Iluid
Belly Walls intact, vent pink, normal shape OIten ruptured, bloated, vent brown, protruding
Organs (including gills) Intact, bright, easily recognizable SoIt to liquid, gray homogeneous mass
Muscle tissue White or characteristic oI species and type White Ilesh pink to gray, spreading oI blood color around backbone
18.4 2002 ASHRAE Refrigeration Handbook
FRESH FISH STORAGE
The maximum storage liIe oI Iish varies with the species. In gen-
eral, the storage liIe oI East and West Coast Iish, properly iced and
stored in reIrigerated rooms at 35°E, is 10 to 15 days. This depends
on the condition oI the Iish when it is unloaded Irom the boat. Gen-
erally, Ireshwater Iish properly iced in boxes and stored in reIriger-
ated rooms may be held Ior only 7 days. Both oI the above time
limitations reIer to the period between when the Iish is landed and
processed to when it is consumed.
Cold storage Iacilities Ior Iresh Iish should be maintained at
about 35°E with over 90° relative humidity. Air velocity should be
limited to control ice loss. Temperatures less than 32°E retard ice
melting and can result in excessive Iish temperatures. This is partic-
ularly important when storing round Iish such as herring, which
generate heat Irom autolytic processes.
Eloors should have adequate drainage with ample slopes toward
drains. All inside surIaces oI a cold storage room should be easy to
clean and able to withstand the corrosive eIIects oI Irequent wash-
ings with antimicrobial compounds.
Irradiation of Fresh Seafood
Ionizing radiation can double or triple the normal shelI liIe oI
reIrigerated, unIrozen Iish and shellIish stored at 33°E (see Table 2).
No oII-odors, adverse nutritional eIIects, or other changes are
imparted to the product as a result oI the radiation treatment. How-
ever, irradiation oI Iish is still not common and is not permitted in
some jurisdictions.
Modified Atmosphere Packaging
A product environment with modiIied levels oI nitrogen, CO

, and
oxygen can curtail the growth oI bacteria and extend shelI liIe oI
Iresh Iish. Eor example, whole haddock stored in a 25° CO

atmo-
sphere Irom the time it is caught keeps about twice as long as it would
in air. However, a modiIied atmosphere does not inhibit all microbes,
and spoilage bacteria, because oI their great number, usually restrict
the growth oI the Iew pathogenic bacteria present. Traditionally, the
obvious signs oI spoilage serve as the saIeguard against eating Iish
that may have dangerous levels oI pathogenic bacteria.
Because modiIied atmosphere packaging can be a saIety hazard,
it is being introduced slowly in several countries under close moni-
toring by regulatory agencies. This type oI packaging requires com-
plete knowledge oI regulations and a good control system that
maintains proper temperature and sanitation levels.
*63>)2*-7,)6=463(9'87
The production oI Irozen Iishery products varies with geograph-
ical location and includes primarily the production oI groundIish Iil-
lets, scallops, breaded precooked Iish sticks, breaded raw Iish
portions, Iish roe, and bait and animal Iood in the northeastern states
and in Atlantic Canada; round or dressed halibut and salmon, hali-
but and salmon steaks, groundIish Iillets, surimi, herring roe, and
bait and animal Iood in the northwestern states and in British
Columbia; halibut, groundIish Iillets, crab, salmon, and surimi in
Alaska (salmon roe in Alaska is called ikura¨); shrimp, oysters,
crabs, and other shellIish and crustacea in the GulI oI Mexico and
South Atlantic states; and round or dressed Iish in the areas border-
ing on the Great Lakes.
The Iish obtained Irom these areas diIIer considerably in both
physical and chemical composition. Eor example, cod or haddock
are readily adaptable to Ireezing and have a comparatively long stor-
age liIe, but other Iatty species, such as mackerel, tend to become
rancid during Irozen storage and thereIore have a relatively short
storage liIe. The diIIerences in composition and marketing require-
ments oI many species oI Iish necessitate consideration oI the spe-
ciIic product with regard to quality maintenance and methods oI
packaging, Ireezing, cold storage, and handling.
Temperature is the most important Iactor limiting the storage liIe
oI Irozen Iish. At temperatures below Ireezing, bacterial activity as
a cause oI spoilage is limited. However, even Iish Irozen within a
Iew hours oI catching and stored at 20°E will deteriorate very
slowly until it becomes unattractive and unpleasant to eat.
Eish proteins are permanently altered during Ireezing and cold
storage. This denaturation occurs quickly at temperatures not Iar
below Ireezing; even at 0°E Iish deteriorates rapidly. Badly stored
Iish is easily recognized: the thawed product is opaque, white, and
dull, and juice is easily squeezed Irom it. Although properly stored
product is Iirm and elastic, poorly stored Iish is spongy, and in very
bad cases, the Ilesh breaks up. Instead oI the succulent curdiness oI
cooked Iresh Iish, cooked denatured samples have a wet and
sloppy consistency at Iirst and, on Iurther chewing, become dry
and Iibrous.
Among other Iactors that determine how quickly quality dete-
riorates in cold storage are the initial quality and composition oI
the Iish, the protection oI the Iish Irom dehydration, the Ireezing
method, and the environment during storage and transport. These
Iactors are reIlected in Iour principal phases oI Irozen Iish pro-
duction and handlingpackaging, Ireezing, cold storage, and
transportation.
Today, many species are brought Irom warm and tropical waters
where parasites and toxins could inIect them. In addition, Iood
dishes that use raw seaIood, such as sushi and sashimi, have gained
wide popularity, making them a potential health risk. Parasites are
not liIe-threatening but can cause pain and inconvenience. They are
easily destroyed by cooking or by deep Ireezing (40°E). Marine
toxins could be deadly and are not aIIected by temperature. Suscep-
tible species should not be eaten during periods when toxins could
be developed.
PACKAGING
Materials Ior packaging Irozen Iish are similar to those Ior other
Irozen Ioods. A package should (1) be attractive and appeal to the
consumer, (2) protect the product, (3) allow rapid, eIIicient Ireezing
and ease oI handling, and (4) be cost-eIIective.
Package Considerations in Freezing
ReIrigeration equipment and packaging materials are Irequently
purchased without considering the eIIect oI the package size on
Ireezing rate and eIIiciency. Eor example, a thin consumer package
results in a Iaster rate oI product Ireezing, lower total Ireezing
Table 2 Optimal Radiation Dose Levels and Shelf Life
at 33°F for Some Species of Fish and Shellfish
Species
Optimal Radiation
Dose, Rads
Air Packed
Shelf Life,
Weeks
Oystersshucked, raw 200,000 3 to 4
Shrimp 150,000 4
Smoked chub 100,000 6
Yellow perch 300,000 4
Petrale sole 200,000 2 to 3 (4 to 5 when vac pac)
PaciIic halibut 200,000 2 (4 when vac pac)
King crabmeat 200,000 4 to 6
Dungeness crabmeat 200,000 3 to 6
English sole 200,000 to 300,000 4 to 5
SoIt-shell clam meat 450,000 4
Haddock 150,000 to 250,000 3 to 4
Pollock 150,000 4
Cod 150,000 4 to 5
Ocean perch 250,000 4
Mackerel 250,000 4 to 5
Lobster meat 150,000 4
Fishery Products 18.5
costs, higher handling costs, and higher packaging material costs; a
thicker institutional-type package results in a slower rate oI prod-
uct Ireezing, higher Ireezing costs, lower handling costs, and lower
packaging material costs.
Tests indicate that the time required to Ireeze packaged Iish Iil-
lets in a plate Ireezer is directly proportional to the square oI the
package thickness. Thus, iI it takes 3 h to Ireeze packaged Iish Iillets
2 in. thick, it takes about 4.7 h to Ireeze packaged Iish Iillets 2.5 in.
thick. The insulating eIIect oI the packaging material, the Iit oI the
product in the package, and the total surIace area oI the package
must be considered. A packing material with low moisture-vapor
permeability has an insulating eIIect, which increases Ireezing time
and cost.
The rate oI heat transIer through packaging material is inversely
proportional to its thickness; thereIore, packaging material should
be (1) thin enough to produce rapid Ireezing and an adequate mois-
ture-vapor barrier in Irozen storage and (2) thick enough to with-
stand heavy abuse. Aluminum Ioil cartons and packages oIIer an
advantage in this regard.
Proper Iit oI package to product is essential; otherwise, the insu-
lating eIIect oI the air space Iormed reduces the Ireezing rate oI the
product and increases Ireezing cost. The surIace area oI the pack-
age is also important because oI its relation to the size oI the Ireezer
shelves or plates. Maximum use oI Ireezer space can be obtained by
designing the package so that it Iits the Ireezer properly. OIten,
however, these Iactors cannot be changed and still meet customer
requirements Ior a speciIic package.
Package Considerations for Frozen Storage
Eish products lose considerable moisture and become tough and
Iibrous during Irozen storage unless a package with low moisture-
vapor permeability is speciIied. The package in contact with the
product must also be resistant to oils or moisture exuded Irom the
product, or rancidity oI the oils and soItening oI the package mate-
rial will occur. The package must Iit the product tightly to minimize
air spaces and thereby reduce moisture migration Irom the product
to the inside surIaces oI the package.
Unless temperatures are very low or special packaging is used,
the oils in Iish will oxidize in Irozen storage, producing an oII-
Ilavor. One eIIective type oI packaging is to replace the air sur-
rounding the Irozen Iish with pure nitrogen and to seal the Iish in
a leak-prooI bag made oI a material that is a barrier to the passage
oI oxygen.
Types of Packages
Packaging materials consist oI either paperboard cartons coated
with various waterprooIing materials or cartons laminated with
moisture-vapor-resistant Iilms and heat-sealable overwrapping
materials with a low moisture-vapor permeability. Paperboard car-
tons are usually made oI a bleached kraIt stock, coated with a suit-
able IortiIied wax, polyethylene, or other plastic material.
Overwrapping materials should be highly resistant to moisture
transmission, inexpensive, heat sealable, adaptable to machinery
application, and attractive in appearance. Various types oI hot melt
coated waxed paper, cellophane, polyethylene, and aluminum Ioil
are available in diIIerent Iorms and laminate combinations to best
suit each product.
Consumer Packages. These usually hold less than 1 lb and are
generally printed, bleached paperboard coated with wax or polyeth-
ylene and closed with adhesive. Eish sticks and portions, shrimp,
scallops, crabmeat, and precooked dinners and entrees are packaged
in this way. In the case oI dinners and entrees, rigid plastic, press-
board, or aluminum trays are used inside the printed paperboard
package. Rigid plastic or pressboard packages are becoming more
common because they are better Ior microwave cooking. The pack-
aging oI these products is normally mechanized.
Materials such as polyethylene combined with cellophane,
polyvinylidene chloride, or polyester and combinations oI other
plastic materials are used with high-speed automatic packaging
machines to package shrimp, dressed Iish, Iish Iillets, Iish portions,
and Iish steaks prior to Ireezing. In some instances, tearing oI the
wrapping material by Iins protruding Irom the Iish has been a
problem. Otherwise, this method oI packaging is satisIactory and
aIIords the product considerable protection against dehydration
and rancidity at a comparatively low cost. This packaging method
has also created new markets Ior merchandising Irozen Iish prod-
ucts. Boil-in-bag pouches made oI polyester-polyethylene and
combinations oI Ioil, polyethylene, and paper are used Ior packag-
ing shrimp, Iish Iillets, and entrees. These packages are also suit-
able Ior microwave cooking.
Institutional Packages. The 5 lb and larger cartons used in the
institutional trade are commonly constructed oI bleached paper-
board that has been waxed or polyethylene coated. Eolding cartons
with selI-locking covers, Iull-telescoping covers, or glued closures
are used. OIten the cartons are packaged inside a corrugated master
carton or are shrink-wrapped in polyethylene Iilm.
Products such as Iish Iillets and steaks are individually wrapped
in cellophane or another moisture-vapor-resistant Iilm and then
packed in the carton. Eish, such as headed and dressed whiting and
scallop meats, are packed into the carton and covered with a sheet oI
cellophane. The cover is then put in place and the package is Irozen
upside down in the Ireezer. Raw, unbreaded products, such as
shrimp, scallops, Iillets, and steaks, are sometimes individually
quick Irozen (IQE) prior to packaging. IQE products can be glazed
to enhance moisture retention. This method is preIerred over Ireez-
ing aIter packaging because it leads to a product that is more con-
venient to handle and sometimes obviates the need to thaw the Iish
beIore cooking.
Eor institutional Irozen Iish, the current trend is toward printed
paperboard Iolding cartons coated with moisture-vapor-resistant
materials instead oI waxed paper or cellophane overwrap, though
shatter pack¨ bulk is also common. Some Irozen Iish products and
seaIood entrees destined Ior institutional markets are packaged in
aluminum trays or in rigid plastic trays so they may be heated within
the package.
FREEZING METHODS
Product characteristics, such as size and shape, Ireezing
method, and rate oI Ireezing, aIIect the quality, appearance, and
cost oI production.
Quick Ireezing oI Iish oIIers the Iollowing advantages:
· Chills the product rapidly, preventing bacterial spoilage
· Eacilitates rapid handling oI large quantities oI product
· Makes use oI conveyors and automatic devices practical, thus
materially reducing handling costs
· Promotes maximum use oI the space occupied by the Ireezer
· Produces a packaged product oI uniIorm appearance, with a min-
imum oI voids or bulges
Eor Iurther inIormation, see Chapters 8, 9, and 15.
Blast Freezing
Blast Ireezers Ior Iishery products are generally small rooms or
tunnels in which cold air is circulated by one or more Ians over an
evaporator and around the product to be Irozen, which is on racks or
shelves. A reIrigerant such as ammonia, a halocarbon, or brine Ilow-
ing through a pipe coil evaporator Iurnishes the necessary reIriger-
ation eIIect.
Static pressure in these rooms is considerable, and air velocities
average between 500 and 1500 Ipm, with 1200 Ipm being common.
Air velocities between 500 and 1000 Ipm give the most economical
18.6 2002 ASHRAE Refrigeration Handbook
Ireezing. Lower air velocities slow down product Ireezing, and
higher velocities increase unit Ireezing costs considerably.
Some Iactories have blast Ireezers in which conveyors move Iish
continuously through a blast room or tunnel. These Ireezers are built
in several conIigurations, including (1) a single pass through the
tunnel, (2) multiple passes, (3) spiral belts, and (4) moving trays or
carpets. The conIiguration and type oI conveyor belt or Ireezing sur-
Iace depend on the type and quantity oI the product to be Irozen, the
space available to install the equipment, and the capital and operat-
ing costs oI the Ireezer.
Batch-loaded blast Ireezers are used Ior Ireezing the Iollowing:
shrimp, Iish Iillets, steaks, scallops, and breaded precooked prod-
ucts in institutional packages; round, dressed, and panned Iish; and
shrimp, clams, oysters, and salmon roe (ikura) packed in metal cans.
Conveyor blast Ireezers are widely used to Ireeze products prior
to packaging. These products include all types oI breaded, pre-
cooked seaIoods; IQE Iillets, loins, tails, steaks, scallops, and
shrimp; and raw, breaded Iish portions. In the case oI portions,
which are sliced or sawed Irom blocks, the Iunction oI the blast
Ireezer is to harden the batter and breading beIore packaging and
lower the temperature oI the Irozen Iish Ior storage iI it has been
tempered Ior slicing.
Dehydration oI product, or Ireezer burn, may occur in Ireezing
unpackaged whole or dressed Iish in blast Ireezers unless the veloc-
ity oI air is kept to about 500 Ipm and the period oI exposure to the
air is controlled. Consumer packages oI Iish Iillets or Iish-Iillet
blocks requiring close dimensional tolerances undergo bulging and
distortion during Ireezing unless restrained. In blast rooms or tun-
nels, the product can be Irozen on specially designed trucks,
enabling distribution oI pressure on the surIaces oI the package and
remedying this condition. It is diIIicult to control the expansion oI
the product on conveyor installations.
Ereezing times Ior various sizes oI packaged Iishery products are
shown in Eigure 2.
Plate Freezing
In the multiplate Ireezer, Ireezing is accomplished by reIriger-
ant Ilowing through connected passageways in horizontal mov-
able plates stacked vertically within an insulated cabinet or room.
The plate Ireezer is used extensively in Ireezing Iishery products
packaged in consumer cartons and in 5 and 10 lb institutional car-
tons. Eish to be plate Irozen should be properly packaged to min-
imize air spaces. Spacers should be used between the plates
during Ireezing to prevent crushing or bulging oI the package. Eor
most products, the thickness oI the spacers should be about 0.03
to 0.06 in. less than that oI the package.
Where very close package tolerances are required, as in the man-
uIacture oI Iish Iillet blocks, a metal Irame or tray is used to hold the
packages oI Iish during Ireezing. The Irame or tray is generally the
same width as the package and the length oI one or two blocks. It
must be rigid enough to prevent bulging and to hold the Iish block`s
dimensions. This is sometimes accomplished with rigid spacers that
limit the weight and cost oI the tray.
Eish blocks are available in two common sizes: 16.5 lb (19 by 10
by 2.5 in.) and 18.5 lb (19 by 11.5 by 2.5 in.). Other blocks are sized
Ior special applications. The Iish can be packed in the block with the
long dimension oI the Iillets along the length oI the Irame (long-pack)
or along the width oI the Irame (cross-pack). The orientation depends
on the eventual cutting pattern and type oI cutting used to convert the
block into a Iinished product.
A tray is not necessary Ior other packaged seaIoods such as
shrimp, Iillets, Iish sticks, or scallops, where close package toler-
ances are not as essential. ThereIore, an automatic continuous plate
Ireezer with properly sized spacers is satisIactory Ior these products.
The plate Ireezer provides rapid and eIIicient Ireezing oI pack-
aged Iish products. The Ireezing time and energy required Ior Ireez-
ing packaged Iish sticks is greater than that Ior Iish Iillets because
heat transIer is slowed by the air space within the package. Energy
required to Ireeze a unit mass oI product increases with thickness.
The Ireezing times oI consumer and institutional size packages oI
Iish Iillets and Iish sticks are shown in Eigure 3.
Immersion Freezing
Immersion in low-temperature brine was one oI the Iirst methods
used Ior quick-Ireezing Iishery products. A number oI direct immer-
Fig. 2 Freezing Time of Fish Fillets and Fish Sticks in Tunnel
Blast Freezer (Air Velocity 500 to 1000 fpm)
Fig. 2 Freezing Time of Fish Fillets and Fish Sticks in Tunnel
Blast Freezer (Air Velocity 500 to 1000 fpm)
Fig. 3 Freezing Time of Fish Fillets and Fish Sticks
in Plate Freezer
Fig. 3 Freezing Time of Fish Fillets and Fish Sticks
in Plate Freezer
Fishery Products 18.7
sion Ireezing machines were developed Ior whole or panned Iish.
These machines were generally unsuitable Ior packaged Iish prod-
ucts, which make up the bulk oI Irozen Iish production, and have
been replaced by methods employing air cooling, contact with
reIrigerated plates or shelves, and combinations oI these methods.
Immersion Ireezing is used primarily Ior the Ireezing oI tuna at
sea and, to a lesser extent, Ior Ireezing shrimp, salmon, and Dunge-
ness crab, as well as king crab and Alaska snow crab (C. opelio).
Extensive research has been conducted on brine Ireezing oI ground-
Iish aboard vessels, but this method is not in commercial use.
An important consideration in immersion Ireezing oI Iish is
selection oI a suitable Ireezing medium. The medium should be
nontoxic, acceptable to public health regulatory agencies, easy to
renew, and inexpensive; it should also have a low Ireezing temper-
ature and viscosity. It is diIIicult to obtain a Ireezing medium that
meets all these requirements. Sodium chloride brine and a mixture
oI glucose and salt in water are acceptable media. The glucose
reduces salt penetration into the Iish and provides a protective glaze.
Liquid nitrogen spray and CO

are coming into wider use Ior IQE
seaIood products such as shrimp. Although the cost per unit mass is
high, Iish Irozen by these methods is oI good quality, there is virtu-
ally no weight loss Irom dehydration, and there are space and equip-
ment savings. The Iish should not be directly immersed in the liquid
nitrogen since this will cause the Ilesh to shatter and rupture.
Immersion Freezing of Tuna. Most tuna harvested by the
United States Ileet is brine-Irozen aboard the Iishing vessel. Ereez-
ing at sea enables the vessel to make extended voyages and return to
port with a Iull payload oI high-quality Iish.
Tuna are Irozen in brine wells, which are lined with galvanized
pipe coils on the inside. Direct expansion oI ammonia into the evap-
orator coils provides the necessary reIrigeration eIIect. The wells
are designed so that tuna can be precooled and washed with reIrig-
erated seawater and then Irozen in an added sodium chloride brine.
AIter the Iish are Irozen, the brine is pumped overboard, and the
tuna are kept in 10°E dry storage. BeIore unloading, the Iish are
thawed in 30°E brine. In some cases, the Iish are thawed in tanks at
the cannery. II the Iish are thawed ashore, thawing on the vessel is
not required beyond the stage needed to separate those Iused
together in the vessel`s wells.
Sometimes tuna are held in the wells Ior a long period prior to
Ireezing or are Irozen at a very slow rate because oI high well tem-
peratures caused by overloading, insuIIicient reIrigeration capacity,
or inadequate brine circulation. These practices have a detrimental
eIIect on product quality, especially Ior smaller Iish, which are more
subject to salt penetration and quality changes. Tuna that are not
promptly and properly Irozen may undergo excessive changes,
absorb excessive quantities oI salt, and possibly be bacteriologically
spoiled when landed. Some Ireezing times Ior tuna oI various sizes
are shown in Eigure 4.
Specialized Contact Freezers. Eish Irozen by this method are
placed on a slowly moving, solid stainless steel belt. This belt con-
veys the Iish Iillets through a tunnel, where they are Irozen not only
by an air blast but also by direct contact between the conveyor belt
and a thin layer oI glycol pumped through the plates that support the
belt. A reIrigerant, such as ammonia or a halocarbon, also Ilows
through separate channels in the plates. This provides the reIrigera-
tion eIIect with minimal temperature diIIerence between the evapo-
rating reIrigerant and the product.
Freezing Fish at Sea
Ereezing Iish at sea has Iound increasing commercial application
in leading Iishery nations such as Japan, Russia, the United King-
dom, Norway, Spain, Portugal, Poland, Iceland, and the United
States. Including Ireezer trawlers, Iactory ships, and reIrigerated
transports in Iisheries, hundreds oI large Ireezer vessels are operat-
ing throughout the world. U.S. Iactory Ireezer trawlers, Iactory
surimi trawlers, and Iloating Iactory ships supplied by catcher vessels
operate oII Alaska. These vessels process mainly Alaskan pollock,
cod, and Ilounder, although they do process other species.
Ereezing groundIish at sea is uncommon in the northeastern
United States largely because Iresh Iish commands a better price
than Irozen Iish. Eor the same reason, East Coast U.S. producers
avoid putting their product into Irozen packs iI they can sell it Iresh.
Hence, much oI the Irozen Iish used in the United States, with the
exception oI Alaskan Iish, is imported Irom other countries.
Where used, the Iactory vessel is equipped to catch, process, and
Ireeze the Iish at sea and to use the waste material in the manuIac-
ture oI Iish meal and oil. A large European Iactory vessel measures
280 It in length, displaces 3700 tons, and is equipped to stay at sea
Ior about 80 days without being reIueled. About 65 to 100 people
are required to operate the vessel and to process and handle the Iish.
On most vessels oI this type, contact-plate Ireezers are used. The
Ireezers can Ireeze about 30 tons oI Iish per day, and the total capac-
ity oI the Irozen Iish hold may be as high as 750 tons.
Because the Iactory trawler stays at sea Ior long periods, it can
Iully use its space Ior storing Iish. However, due to limited available
labor, Irozen packs are generally oI the less labor-intensive types.
The Ireezer trawler was designed to resolve the disadvantages
associated with Iactory Ireezer vessels. It is smaller and equipped to
Ireeze Iish in bulk Ior later thawing and processing ashore. Ereezer
trawlers use vertical plate Ireezers to Ireeze dressed Iish in blocks oI
about 100 lb.
Some countries use Ireezer trawlers to supply raw material to
shore-based processing plants producing Irozen Iish products. This
allows the trawlers to Iill their holds in distant waters and transport
the Iish to home base, where it becomes Irozen raw material that is
held in storage until required Ior processing. In some cases, trawlers
have been designed as dual Iisheries, Iishing and Ireezing ground-
Iish blocks during part oI the year and catching, processing, and
Ireezing Northern shrimp Ior the rest oI the year.
STORAGE OF FROZEN FISH
Eishery products may undergo undesirable changes in Ilavor,
odor, appearance, and texture during Irozen storage. These
changes are attributable to dehydration (moisture loss) oI the Iish,
oxidation oI the oils or pigments, and enzyme activity in the Ilesh.
Fig. 4 Freezing Time for Tuna Immersed in Brine
Fig. 4 Freezing Time for Tuna Immersed in Brine
18.8 2002 ASHRAE Refrigeration Handbook
The rate at which these changes occur depends on (1) the composi-
tion oI the species oI Iish, (2) the level and constancy oI storage
room temperature and humidity, and (3) the protection aIIorded the
product through the use oI suitable packaging materials and glaz-
ing compounds.
Composition
The composition oI a particular species oI Iish aIIects its Irozen
storage liIe considerably. Eish with high oil content, such as some
species oI salmon, tuna, mackerel, and herring, have a comparatively
short Irozen storage liIe because oI the development oI rancidity as
a result oI the oxidation oI the oils and pigments in the Ilesh. Certain
Iish, such as sableIish, are quite resistant to oxidative deterioration in
Irozen storage, despite their high oil content. The development oI ran-
cidity is less pronounced in Iish with a low oil content. ThereIore, lean
Iish such as haddock and cod, iI handled properly, can be kept in Iro-
zen storage Ior many months without serious loss oI quality. The rel-
ative susceptibility oI various species oI Iish to oxidative changes
during Irozen storage is shown in Table 3.
Temperature
The quality loss oI Irozen Iish in storage depends primarily on
temperature and duration oI storage. Eish stored at 20°E has a
shelI liIe oI more than a year. In Canada, the Department oI Eisher-
ies recommends a storage temperature oI 15°E or lower. Storage
above 10°E, even Ior a short period, results in rapid loss oI quality.
Time-temperature tolerance studies show that Irozen seaIoods have
memory; that is, each time they are subjected to high temperatures
or poor handling practices, the loss in quality is recorded. When the
product is Iinally thawed, the total eIIect oI each exposure to mis-
treatment is reIlected in the quality oI the product at the consumer
level. Continuous storage at temperatures lower than 15°E reduces
oxidation, dehydration, and enzymatic changes, resulting in longer
product shelI liIe. Erom the time they are Irozen until they reach the
consumer, Irozen seaIoods should be kept at temperatures as close
to 15°E as possible. The shelI liIe oI Irozen Iish products stored at
diIIerent temperatures is given in Table 4. Note the increase in shelI
liIe at the lowest temperatures.
Eor many years, it was thought too costly to operate reIrigerated
warehouses at temperatures lower than 10°E. However, improve-
ments in the design and operation oI reIrigeration equipment have
made such temperatures economically possible. The production oI
surimi by West Coast-based Iactory ships has resulted in the con-
struction oI ultracold rooms Ior its storage. Japanese standards call
Ior this product to be kept at 22°E.
Humidity
A high relative humidity in the cold storage room tends to reduce
the evaporation oI moisture Irom the product. The relative humidity
oI air in the reIrigerated room is directly aIIected by the temperature
diIIerence between room cooling coils and room temperature. A
large temperature diIIerence results in decreased relative humidity
and an accelerated rate oI moisture withdrawal Irom the Irozen
product. A small temperature diIIerence between the air and evap-
orator cooling coils results in high relative humidity and reduced
moisture loss Irom the product.
The relative humidity in commercial cold storages is 10 to 20°
higher than that oI an empty cold storage because oI constant evap-
oration oI moisture Irom the product. In a cold storage operating at
0°E, with a 70° rh and pipe coil temperature oI 10°E, the
moisture-vapor pressure oI the air within the package (in direct
contact with the Irozen Iish) would be 0.0185 psia. The air in the
cold storage would have a vapor pressure oI 0.0132 psia, and the
moisture-vapor pressure at the coils would be 0.0108 psia. These
diIIerences in moisture-vapor pressure will result in considerable
moisture loss Irom the product unless it is adequately protected by
suitable packaging materials or glazing compounds. The evapora-
tor coils in the Ireezer should be sized properly so that the desired
high relative humidities can be obtained. However, because oI
material costs and space limitations, a temperature diIIerence oI
10°E between evaporator coils and room air is the most practical.
Packaging and Glazing
Adequate packaging oI Iishery products is important in prevent-
ing product dehydration and consequent quality loss. The packag-
ing, which, in most instances, occurs beIore Ireezing, has been
described. Individual Iish, whether Irozen in the round or dressed,
cannot usually be suitably packaged; thereIore, they must be pro-
tected by a glazing compound.
A glaze acts as a protective coating against the two main causes
oI deterioration during storage: dehydration and oxidation. It pro-
tects against dehydration by preventing moisture Irom leaving the
product and against oxidation by mechanically preventing air
Table 3 Relative Susceptibility of Representative Species
of Fish to Oxidative Changes in Frozen Storage
Severe Moderate Minor Very Slight
Pink salmon Chum salmon Cod Yellow pike
RockIish Coho salmon Haddock Yellow perch
Lake chub King salmon Elounder Crab
Whiting Halibut Sole Lobster
Ocean perch SableIish
Herring Oysters
Mackerel
Tuna
Lake herring
Sheepshead
Lake trout
Table 4 Effect of Storage Temperature on
Shelf Life of Frozen Fishery Products
Product Temperature, °F Shelf Life, Months
Packaged haddock Iillets 10 4 to 5
0 11 to 12
20 Longer than 12
Packaged cod Iillets 10 5
0 6
10 10 to 11
Packaged pollock Iillets* 20 1
10 2
0 8
10 11
20 24
Packaged ocean perch Iillets 15 1.5 to 2.0
10 3.5 to 4.0
0 6 to 8
10 9 to 10
Packaged striped bass Iillets 15 4
0 9
Glazed whole halibut 10 3
0 6
10 9
20 12
Whole blue Iin tuna 10 4
0 to 5 8
20 12
Glazed whole herring 0 6
17 9
Packaged mackerel Iillets 15 2
0 3
10 3 to 5
*Prepared Irom 1-day-old iced Iish.
Fishery Products 18.9
contact with the product. It may also minimize these changes chem-
ically with an antioxidant.
Maximum storage liIe oI Iishery products can be obtained by
employing the Iollowing procedures:
· Select only high-quality Iish Ior Ireezing.
· Use moisture-vapor-resistant packaging materials and Iit package
tightly around product, or use a modiIied atmosphere and oxygen-
barrier package.
· Ereeze Iish immediately aIter processing or packaging.
· Glaze Irozen Iish prior to packaging.
· Glaze round, unpackaged Iish prior to cold storage.
· Put Iish in Irozen storage immediately aIter Ireezing and glazing,
iI required.
· Store Irozen Iish at 15°E or lower.
· Renew glaze on round, unpackaged Iish as required during Irozen
storage.
The recommended protection and expected storage liIe Ior vari-
ous species oI Iish at 0°E are shown in Table 5.
Space Requirements
Packaged products such as Iillets and steaks are usually packed
in cardboard master cartons Ior storage and shipment. These master
cartons are stacked on pallets and transIerred to various areas oI the
cold storage room by IorkliIt. The master cartons are strong enough
to support one or two pallet loads placed on the shelI oI each rack in
the cold storage. In cold storages without racks, cartons should be
stacked to a height that does not cause crushing oI the bottom car-
tons. Cartons Ior products in packages that contain a lot oI air, such
as IQE Iillets, must be stronger than those Ior solid packages oI Iish
in order to resist crushing during storage.
Whole or dressed Iish Irozen in blocks in metal pans, such as
mackerel, chub, or whiting, are removed Irom the pans aIter Ireez-
ing, glazed, and then packaged in wooden boxes lined with wax-
impregnated paper or in cardboard cartons.
Round Iish stored in wooden boxes can be easily reglazed at peri-
odic intervals during Irozen storage. The space requirements Ior the
storage oI Iishery products are shown in Table 6.
Thawing Frozen Fish. Erozen Iishery products can be thawed
by circulating air or water. In thawing, the Iish should not be allowed
to rise above reIrigerated temperatures; otherwise, rapid deteriora-
tion may occur. Thawing is a slower and more diIIicult process than
Ireezing when done to ensure that quality is maintained. Each appli-
cation should be careIully designed.
TRANSPORTATION AND MARKETING
Conditions oI temperature and humidity recommended Ior
Irozen storage should also be applied during transportation and
marketing to minimize product quality loss. Shipment in nonre-
Irigerated or improperly reIrigerated carriers, exposure to high
ambient temperatures during transIer Irom one environment to
another, improper loading oI common carriers or display cases,
equipment Iailure, and other poor practices lead to increased prod-
uct temperature and, consequently, to quality loss.
Erozen Iish is transported under mechanical reIrigeration in
trucks, railroad cars, or ships. Most oI these vehicles are capable
oI maintaining temperatures oI 0°E or lower. Additional inIorma-
tion on equipment used in the transportation and marketing oI Iro-
zen Iish and other Ioods is given in Chapters 10, 12, 13, 29, 30, 31,
and 47 oI this volume and in Chapter 28 oI the 1994 ASHRAE
HandbookRefrigeration.
To minimize quality loss during transportation and marketing,
the Iollowing procedures should be adhered to:
1. Transport Irozen Iish in reIrigerated carriers (mechanical or
dry ice systems) with ample capacity to maintain a temperature
oI 0°E over long distances.
2. Precool reIrigerated carriers to at least 10°E beIore loading.
3. Remove Irozen products Irom the warehouse only when the
carrier is ready to be loaded. Load directly into the reIrigerated
carrier; do not allow the product to sit on the dock.
4. Check the Irozen Iish temperature with a thermometer beIore
loading.
5. Do not stack Irozen Iish directly against Iloors or walls oI the
carrier. Provide Iloor and wall racks or strips to permit air cir-
culation around the entire load.
6. Continuously record the temperature oI the reIrigerated carrier
during transit. Use an alarm to warn oI equipment Iailure.
7. Measure the temperature oI the product when it is removed
Irom the common carrier at its destination.
8. II products are shipped in an insulated container, apply suIIi-
cient dry ice to maintain temperatures oI 0°E or lower Ior the
duration oI the trip.
9. Maintain Iood delivery or breakup rooms at 0 to 10°E. Do not
hold products in breakup rooms any longer than necessary.
10. When received at the retail store, place the product in a 0°E
storage room immediately.
11. Hold display cases in retail stores at 0°E or lower.
12. Do not overload display cases, especially above the Irost line.
13. Record the temperature oI the display cases. Provide an alarm
to warn oI an excessive rise in temperature.
Table 5 Storage Conditions and Storage Life of Frozen Fish
Fish Recommended Protection` Storage Life (0°F), Months
Chub, pink salmon Ice glazing and packaging 4-6
Mackerel, sea herring, pollock, chub, smelts Ice glazing and packaging 5-9
PaciIic sardines, tuna Packaging 4-6
BuIIaloIish, Ilounder, halibut, ocean perch, rockIish, sableIish,
red, sockeye, silver or coho salmon, whiting, shrimp Packaging 7-12
Haddock, blue pike, cod, hake, lingcod Packaging Over 12
*All packaging should be with moisture-resistant Iilms.
Table 6 Space Requirements for Frozen Fishery Products
Commodity Product Package Container for Storage Space Required, lb/ft

Eish sticks, breaded shrimp, breaded scallops 8 or 10 oz Corrugated master containers 25 to 30
Eish Iillets, Iish steaks, small dressed Iish 1, 5, or 10 lb Corrugated master containers 50 to 60
Shrimp 2.5 and 5 lb Corrugated master containers 35
Panned, Irozen Iish (mackerel, herring, chub) None Wooden or Iiberboard boxes 35
Round halibut None Wooden box 30 to 35
Stacked loose 38
Round groundIish (cod, etc.) None Stacked loose 32
Round salmon None Stacked loose 33 to 35
18.10 2002 ASHRAE Refrigeration Handbook
14. Because oI the accelerated deterioration oI Irozen Iish products
in the distribution and retail chain, hold products in these areas
Ior as short a period as possible.
BIBLIOGRAPHY
Barnett, H.J, R.W. Nelson, P.J. Hunter, S. Bauer, and H. Groninger. 1971.
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the preservation oI whole Iish. Fishery Bulletin 69(2).
Bibek, R. 1996. Fundamental food microbiology. CRC Press, Boca Raton,
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Charm, S.E. and P. Moody. 1966. Bound water in haddock muscle
ASHRAE Journal 8(4):39.
Dassow, J.A. and D.T. Miyauchi. 1965. Radiation preservation oI Iish and
shellIish oI the Northeast PaciIic and GulI oI Mexico. L.J. Ronsivalli,
M.A. Steinberg, and H.L. Seagran, eds. Radiation preservation of
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Eeiger, E.A. and C.W. du Bois. 1952. Conditions aIIecting the quality oI
Irozen shrimp. Refrigerating Engineering (September):225.
Holston, J. and S.R. Pottinger. 1954. Some Iactors aIIecting the sodium
chloride content oI haddock during brine Ireezing and water thawing.
Food Technology 8(9):409.
Kader, A.A., ed. 1992. Postharvest technology of horticultural crops,
2nd ed. University oI CaliIornia Division oI Agriculture and Natural
Resources.
NACMCE. 1992. Hazard Analysis and Critical Control Point System. Inter-
national Journal of Food Microbiology 16:1-23.
Nelson, R.W. 1963. Storage liIe oI individually Irozen PaciIic oyster meats
glazed with plain water or with solutions oI ascorbic acid or corn syrup
solids. Commercial Fisheries Review 25(4):1.
Peters, J.A. 1964. Time-temperature tolerance oI Irozen seaIood. ASHRAE
Journal 6(8):72.
Peters, J.A., E.H. Cohen, and E.J. King. 1963. EIIect oI chilled storage on the
Irozen storage liIe oI whiting. Food Technology 17(6):109.
Peters, J.A. and J.W. Slavin. 1958. Comparative keeping quality, cooling
rates, and storage temperatures oI haddock held in Iresh water ice and salt
water ice. Commercial Fisheries Review 20(1):6.
Ronsivalli, L.J. and J.W. Slavin. 1965. Pasteurization oI Iishery products
with gamma rays Irom a cobalt 60 source. Commercial Fisheries Review
27(10):1.
Stansby, M.E., ed. 1976. Industrial fishery technology, 2nd ed. Robert E.
Krieger Publishing Co., Huntington, NY.
Tressler, D.K, W.B. van Arsdel, and M.J. Copley, eds. 1968. The free:ing
preservation of foods, 4th ed. AVI Publishing, Westport, CT.
Wagner, R.L, A.E. Bezanson, and J.A. Peters. 1969. Eresh Iish shipments in
the BCE insulated leakprooI container. Commercial Fisheries Review
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