seafood imports needed to satisfy an 

 American hunger for the ocean's 

 bounty that outstrips domestic 

 supply. 



In short, freezing is a more 

 efficient, more economical and now 

 a more quality-conscious way to sell 

 seafood. 



But how do processors produce a 

 high quality frozen product? 



"They plan ahead," says David 

 Green, Sea Grant's seafood technol- 

 ogy specialist. "They use appropriate 

 handling and freezing techniques 

 with prime quality fish or shellfish. 

 Freezing is their intention from the 

 beginning; they don't use freezing as 

 a salvage method." 



In freezing seafood. Green says it 

 is imperative to lower the tempera- 

 ture on seafood quickly because ice 

 crystals will form as water in the 

 flesh freezes. These ice crystals can 

 tear the flesh, thus affecting the 

 textural quality of the fish. So 

 processors strive to drop the internal 

 temperature of seafood as fast as 

 possible, particularly in the zone of 

 crystalization between 32 F and 

 22 F. 



Once seafood is frozen, keeping 



it consistently cold is also important. 

 Fish and shellfish must be kept 

 below zero, preferably below -10 F 

 to maintain quality. Your home 

 freezer holds foods between zero and 

 10 F; commercial freezers, between 

 -10 F and -20 F. The Japanese, who 

 have a partiality for quality seafood, 

 store their minced fish at -30 F and 

 their sushi-grade tuna at a frigid 

 -80 F. 



Inside the freezer, frozen fish 

 and shellfish can come up against 



By freezing 



freshly caught seafood 



in prime condition 



and holding it at 



very cold temperatures, 



processors can lock in 



the high quality that 



consumers demand. 



another problem: freezer bum or 

 dehydration. Processors commonly 

 prevent this problem by water 

 glazing or using a moisture-barrier 

 film or vacuum pouch. 



Dehydration presents a problem 

 for anyone who freezes, be it the 

 home cook or the food processor, 

 because of the mechanics of freezer 

 technology. Freezers are designed to 

 remove the heat, or thermal energy, 

 from products by using compounds 

 called refrigerants that boil at very 

 low temperatures. 



Liquid refrigerants, usually freon 

 or ammonia, are pumped into a 

 freezer through evaporation coils. 

 Since refrigerants boil at tempera- 

 tures well below zero, they vaporize 

 inside the coils, which are exposed to 

 the relatively warm confines of the 

 freezer. 



As the refrigerant vaporizes into 

 a gas, it absorbs heat. The heat- 

 absorbed gas is pumped back to the 

 compressor to be liquefied under 

 very high pressure in the condenser 

 coils. This compression process 

 generates heat, and that's why the 

 back or bottom of the freezer is 

 always warm. 



I 6 MARC HI APRIL 1993 



