ASHRAE REFRIGERATION IP CH 32-2010 FISHERY PRODUCTS《渔业产品》.pdf

1、32.1CHAPTER 32FISHERY PRODUCTSFRESH FISHERY PRODUCTS . 32.1Care Aboard Vessels 32.1Shore Plant Procedure and Marketing 32.2Packaging Fresh Fish. 32.3Fresh Fish Storage . 32.3FROZEN FISHERY PRODUCTS. 32.4Packaging . 32.4Freezing Methods . 32.5Storage of Frozen Fish . 32.7Transportation and Marketing

2、. 32.9HE major types of fish and shellfish harvested from NorthTAmerican waters and used for food include the following: Groundfish (haddock, cod, whiting, flounder, and ocean perch),lobster, clams, scallops, snow crab, shrimp, capelin, herring, andsardines from New England and Atlantic CanadaOyster

3、s, clams, scallops, striped bass, and blue crab from theMiddle and South AtlanticShrimp, oysters, red snapper, clams, and mullet from the Gulf CoastLake herring, chubs, carp, buffalofish, catfish, yellow perch, andyellow pike from the Mississippi Valley and Great LakesAlaska pollock, Pacific pollock

4、, tuna, halibut, salmon, Pacificcod, various species of flatfish, king and snow crab (Chinoecetesopelio; about 200,000,000 lb annually), dungeness crab, scallops,shrimp, and oysters from the Pacific Coast and AlaskaCatfish, salmon, trout, oysters, and mussels from aquacultureoperations in various lo

5、cationsFish harvested from tropical waters are reported to have a sub-stantially longer shelf life than fish harvested from cold waters, pos-sibly because of the bacterial flora naturally associated with the fish.Bacteria associated with fish from tropical waters are mainly gram-negative mesophiles,

6、 whereas those that cause spoilage of fish dur-ing refrigerated storage are usually gram-negative psychrophiles.The time required for this bacterial population shift (from meso-philes to psychrophiles) after refrigeration may account for theincreased shelf life.The major industrial fish used for fis

7、h meal and oil is menhadenfrom the Atlantic and Gulf coasts. Also, fish parts not used forhuman consumption are often used to manufacture fish meal and oil.Fish meal and oil are the principal components of feed used in theaquaculture of trout and salmon, and is a dietary component forpoultry and pig

8、s. Fish oil is used in margarine, in paints, and in thetanning industry. It is also refined for pharmaceutical purposes.This chapter covers preservation and processing of fresh and fro-zen fishery products; handling of fresh fish aboard vessels andashore; the technology of freezing fish; and present

9、 commercialtrends in freezing, frozen storage, and distribution of seafood.See Chapter 40 for additional information regarding fisheryproducts for precooked and prepared foods, and Chapter 26 formore on marine refrigeration.HACCP System. Many procedures for control of microorgan-isms are managed by

10、the Hazard Analysis and Critical ControlPoint (HACCP) system of food safety. Each food manufacturingsite should have a HACCP team to develop and implement itsHACCP plan. See Chapter 22 for additional information on sanita-tion.FRESH FISHERY PRODUCTSCARE ABOARD VESSELSAfter fish are brought aboard a

11、vessel, they must be promptly andproperly handled to ensure maximum quality. Trawl-caught fish onthe New England and Canadian Atlantic coasts, such as haddockand cod, are usually eviscerated, washed, and then iced down in thepens of the vessels hold. Canadian (offshore), Icelandic, U.K., andother Eu

12、ropean fleets ice fish in boxes for optimum quality. Becauseof their small size, other groundfish (e.g., ocean perch, whiting,flounder) are not eviscerated and are not always washed. Instead,they are iced down directly in the hold of the vessel.Crustaceans, such as lobsters and many species of crabs

13、, are usu-ally kept alive on the vessel without refrigeration. Warm-watershrimp are beheaded, washed, and stored in ice in the hold; on somevessels, however, the catch is frozen either in refrigerated brine or inplate freezers. Cold-water shrimp are stored whole in ice or inchilled sea water, or the

14、y may be cooked in brine, chilled, and storedin containers surrounded with ice.Freshwater fish in the Great Lakes and Mississippi River areasare caught in trap nets, haul seines, or gill nets. They are sortedaccording to species into 50 or 100 lb boxes, which are kept on thedeck of the vessel. In mo

15、st cases, fishing vessels carry ice aboard,and fish are landed the day they are caught.Freshwater fish in Canadian lakes are iced down in the summer-time and stored at collecting stations on the lakes, where they arepicked up by a collecting boat with a refrigerated hold. Winter-caught Canadian fres

16、hwater and Arctic saltwater fish are usuallyweather-frozen on the ice immediately after catching and are mar-keted as frozen fish.Line-caught fish of the Pacific Northwest, such as halibut caughtlargely by bottom long-line gear and salmon caught by trolling gear,are eviscerated, washed, and iced in

17、the pens of the vessel. Pacificsalmon caught by seines and gill nets for cannery use are usuallystored whole for several days, either aboard vessels or ashore in tanksof seawater refrigerated to 30F. A small but significant volume ofhalibut is held similarly in refrigerated seawater aboard vessels.

18、Tunacaught offshore by seiners or clipper vessels are usually brine-frozenat sea. However, tuna caught inshore by smaller trollers or seiners areoften iced in the round or refrigerated with a brine spray.Fish raised by aquaculture farms are usually harvested and soldas required by the fresh fish mar

19、ket. They are usually shipped incontainers in which they are surrounded by ice.IcingFish lose quality because of bacterial or enzymatic activity orboth. Reducing storage temperature retards these activities signifi-cantly, thus delaying spoilage and autolytic deterioration.Low temperatures are parti

20、cularly effective in delaying growth ofpsychrophilic bacteria, which are primarily responsible for spoilageof nonfatty fish. The shelf life of species such as haddock and cod isdoubled for each 7 to 10F decrease in storage temperature withinthe range of 60 to 30F.The preparation of this chapter is a

21、ssigned to TC 10.9, Refrigeration Appli-cation for Foods and Beverages.32.2 2010 ASHRAE HandbookRefrigerationTo be effective, ice must be clean when used. Bacteriologicaltests on ice in the hold of a fishing vessel showed bacterial counts ashigh as 5 billion per gram of ice. These results indicate t

22、hat (1) chlo-rinated or potable water should be used to make the ice at the plant,(2) ice should be stored under sanitary conditions, and (3) unusedice should be discarded at the end of each trip.Both flake and crushed block ice are used aboard fishing vessels,although flake ice is more common becau

23、se it is cheaper to produceand easier to handle mechanically.The amount of ice used aboard vessels varies with the particularfishery and vessel; however, it is essential to provide enough icearound the fish to obtain a proper cooling rate (Figure 1). A com-mon ratio of ice to fish used in bulk icing

24、 on New England trawlersis one part ice to three parts fish. Experiments on British trawlersin boxing fish at sea with one part ice to two parts fish demon-strated improved quality in the landed fish, and, as ice has becomemore plentiful and less costly relative to the value of fish, the ratioof ice

25、 to fish continues to increase. Some vessels use mechanicalrefrigeration to retard ice melting en route to the fishing grounds;however, the hold temperature must be controlled after fish aretaken to allow the ice to melt for effective cooling of the fish.Saltwater IcingIced fish storage temperatures

26、 must be maintained close to thefreezing point of fish. To obtain lower ice temperatures, the freez-ing point may be depressed by adding salt to the water from whichice is made. Adequate amounts of ice made from a 3% solution ofsodium chloride brine maintain a storage environment of about30F. Tests

27、conducted on haddock storage in saltwater ice aboard afishing vessel showed that, under parallel conditions, fish iced withsaltwater ice cooled more quickly and to a lower temperature thanfish iced with plain ice. However, the saltwater ice melted morequickly because of its lower latent heat and gre

28、ater temperaturedifferential. Therefore, once the saltwater ice melted, fish stored inthis ice rose to a higher temperature than those in plain ice.Because it is not always possible to replenish ice on fish at sea, suf-ficient quantities of saltwater ice must be used initially to make upfor its fast

29、er melting rate.In making ice from water containing a preservative, rapid freez-ing and/or using a stabilizing dispersant is essential to preventmigration of the additive to the center of the ice block. This prob-lem is not encountered in flake ice because flake ice machinesfreeze water rapidly into

30、 thin layers of ice, thus fixing additiveswithin the flakes. Chapter 43 describes the manufacture of flakeice in more detail.Use of PreservativesIn the United States and Canada, the use of antibiotics in ice or indips for treatment of whole or gutted fish, shucked scallops, andunpeeled shrimp is pro

31、hibited by regulation.Storage of Fish in Refrigerated SeawaterRefrigerated seawater (RSW) is used commercially for preserv-ing fish. On the Pacific Coast, substantial quantities of net-caughtsalmon are stored in RSW aboard barges and cannery tenders fordelivery to the canneries. Most salmon seiners

32、now use RSW sys-tems. It is often a condition of sale. On the East and Gulf coasts,RSW installations on fishing vessels are used for chilling and hold-ing menhaden and industrial species needed for production ofmeal, oil, and pet food. On the east and west coasts of Canada,RSW installations are used

33、 for chilling and holding herring andcapelin, which are processed on shore for their roe. Other, morelimited applications of RSW include holding Pacific halibut andGulf shrimp aboard a vessel; chilling and holding Maine sardinesin shore tanks for canning, and short-term holding of Pacificgroundfish

34、in shore tanks for later filleting.With groundfish and shrimp, RSW works well for short-termstorage (2 to 4 days), but is not suitable for longer periods becauseexcessive salt uptake, accelerated rancidity, poorer texture, andincreased bacterial spoilage may result. These problems can bepartially ov

35、ercome by introducing carbon dioxide (CO2) gas intothe RSW; holding in RSW saturated with CO2can increase thestorage life of some species of fish by about 1 week. Additionally,RSW reduces (1) handling that results from bulk storage of the fishand (2) pressure on the fish as a result of buoyancy, fas

36、ter cooling,and lower storage temperature.In many RSW systems, refrigeration is provided by ammoniaflowing through external chillers (which gives the best results) orpipe coils in the tanks.Boxing at SeaThere are many advantages to using containers or boxes insteadof bulk storage aboard fishing vess

37、els. Using containers reducespressure on fish stowed in a vessels hold. Because significantreductions in handling during and after unloading are possible,mechanical damage and product temperature rise may be virtuallyeliminated, and handling costs may be reduced. Fish can be sortedinto boxes by size

38、 and species as soon as they are caught. Boxedfish lend themselves more readily to mechanized handling, such asmachine filleting, because they are generally firmer and of moreuniform shape; fillet yields are generally better than they are withbulk-stored fish.Boxing at sea is not generally practiced

39、 in the United States,except by some inshore vessels. The principal problems with con-verting a fishing vessel from bulk to boxed storage are increasedlabor required by the crew for handling the boxes, reduced holdcapacity, and relatively large investment for boxes. Many fisherieshave difficulties w

40、orking out the logistics for ensuring promptreturn of properly cleaned boxes to the vessel. Most of these prob-lems have been solved in European, Canadian (offshore), andSouth American (hake) fleets. Using nonreturnable containers forboxing at sea simplifies logistics and reduces initial capital out

41、lay;it has proved justifiable in some U.S. fisheries.Reusable containers for boxing at sea are usually made of plastic.Careful icing is necessary to minimize the surface area of fish incontact with the box. Plastic provides more heat transfer resistancethan aluminum in vessels with uninsulated fish

42、holds and for in-plant storage prior to processing.All fish boxes must be equipped with drains, preferably directedoutside the boxes on the bottom of a stack.SHORE PLANT PROCEDURE AND MARKETINGProper use of ice and adherence to good sanitary practices ensuremaintenance of iced fish freshness during

43、unloading from the ves-sel, at the shore plant, during processing, and throughout the distri-bution chain. Fish landed in good quality spoil rapidly if thesepractices are not carried out.Fig. 1 Cooling Rate of Properly and ImproperlyIced HaddockFig. 1 Cooling Rate of Properly and Improperly Iced Had

44、dockFishery Products 32.3Fish unloaded from the vessel are usually graded by the buyer forspecies, size, and minimum quality specification. A price is based inpart on the quality in relation to market requirements. Fish also maybe inspected by local and federal regulatory agencies for whole-someness

45、 and sanitary condition. Organoleptic criteria are mostimportant for evaluating quality; however, there is a growing accep-tance, particularly in Canada and some European countries, ofobjective chemical and physical tests as indexes of quality loss orspoilage. Organoleptic (sensory) quality criteria

46、 vary somewhatamong species, but the information in Table 1 can be used as a gen-eral guide in judging the quality of whole fish.In New England and the Canadian Atlantic provinces, ground-fish may be placed in boxes and trucked to the shore plant or con-veyed directly from the hold or deck to the sh

47、ore plant. Single- ordouble-wall insulated boxes are normally used; wooden boxes arerarely used because they are a source of microbiological contami-nation. Ice should be applied generously to each box of fish, even ifthe period before processing is only a few hours. Fish awaiting pro-cessing for mo

48、re than a few hours should be iced heavily and storedin insulated containers or in single-wall boxes in a chill room refrig-erated to 35F. If refrigerated facilities are not available, boxes offish should be kept in a cool section of the plant that is clean and san-itary and has adequate drainage.La

49、rge boxes of resin-coated plywood or reinforced fiberglassthat hold up to 1000 lb of fish and ice are used by some plants inpreference to icing fish overnight on the floor. These tote boxes aremoved and stacked by forklift, can be used for trucking fish to otherplants, and make better use of plant floor space. Generally, fishawaiting processing should not be kept longer than overnight.Fresh fish are marketed in different forms: fillets, whole fish,dressed-head on, dressed-headed (head removed), and, in some in-stances, steaks. The method of preparing fish for marketing dependslargel