364 FOOD SCIENCE APPLICATIONS 



oils and the low sodium content of many species of fish make them 

 especially useful in therapeutic diets. 



The fact that fish and shellfish are readily available sources of generous 

 amounts of complete protein and of a great variety of protective vitamins 

 and minerals makes them a most valuable food for women during preg- 

 nancy and lactation, for children during their periods of growth and 

 maturation, and for our growing population of senior citizens. 



Seasonal Factors. The informed consumer is infiuenced in the choice 

 of species by the season of the year. Many species are available fresh 

 only during a relatively short season. Out-of-season fish may have been 

 held for a long period in frozen storage. These fish may have developed 

 rancidity in such oily areas as the belly flaps or along the lateral line. 

 Often, such fish can be improved by removing the rancid areas before 

 cooking. 



Cost to Consumer. The price per pound of fish varies in relation to 

 availability and the amount of labor invested in its preparation for mar- 

 ket. The availability of a particular species is determined by its abun- 

 dance, the proximity of the area where it is caught, and the consumer 

 demand for the product. 



Fillets of fish represent from 20 to 40 per cent of the weight of the 

 whole fish. The consumer can thus afford to pay considerably more per 

 pound for fillets than for the whole fish. In fish production areas there 

 will always be the opportunity for the consumer to save labor costs by 

 purchasing fish in the round and dressing them herself. 



Quality Criteria 



Flavors and Odor. The odor of iced fish ordinarily changes from the 

 moment of capture through storage to the point of inedibility following 

 a general pattern as shown in Table 28.1. At stage 1, most fish possess 

 an odor and flavor characteristic of the species. These odors and flavors 



Table 28.1. Usual Pattern of Odor Stages Found in Fish Stored in Ice 



Stage Name Description 



Normal odor characteristic for species predominating 

 Absence or decrease of normal spocios characteristic odor 

 Onset of first faint decomposition odors often associated with 

 fish but without any connotation of undesirability 



4 Sweet Continuation of build-up of odors associated with stage 3 but 



still without any connotation of undesirability 



5 Stale Arrival at stage where "off" odors are considered undesirable 



but fish may still be barely acceptable 

 *6 Putrid Stage where fish is definitely unacceptable^ for human consump- 



tion 



