366 FOOD SCIENCE APPLICATIONS 



out of moisture from the tissue. As a result of deteriorative changes dur- 

 ing handling, texture tends to deviate from this norm in one of two ways. 

 At one extreme, the fish appears dry and tough when eaten and little 

 moisture can be felt at the surfaces. This condition is encountered with 

 frozen fish which has been stored for too long or in an improper manner. 

 It results from several types of changes which may occur including dehy- 

 dration, formation of drip during thawing which is not readsorbed before 

 cooking, or by denaturation of the protein during storage. 



At the other extreme is a mushy condition whereby during chewing 

 excessively large quantities of fluid are expressed from the fish. This 

 condition is generally caused by proteolysis during refrigerated, above- 

 freezing storage prior to any subsequent handling (such as freezing). 



Quality Specifications and Standards 



In buying and selling fishery products some type of product specifi- 

 cation and an accepted level of quality are essential. To determine the 

 product quality one must consider systematically the characteristics that 

 determine its value to the buyer. 



Determining Quality. Detailed purchase specifications (with inclusion 

 of applicable standards) may be used by an exacting buyer with inde- 

 pendent inspection checks to assure compliance and the desired level of 

 quality. The purchase order is the obvious place for specifying product 

 species, form, size, or unit package, and delivery requirements. Therefore 

 the simplest type of quality inspection is an assurance of compliance with 

 purchase requirements. The buyer often assumes the quality to be whole- 

 some and merchantable, but quality may fluctuate with supply and 

 demand. Availability of fishery products is frequently dependent on un- 

 controlled factors of season, weather, and fish distribution; therefore, 

 shortages or gluts may provide problems. 



Legal requirements include compliance with applicable regulations of 

 the U.S. Food and Drug Administration and state or local governments. 

 Product identity, fill of container or net weight provisions, assurance of 

 wholesomeness, and proper labeling are key factors. Sanitation require- 

 ments for the product usually imply exclusion or limitation of micro- 

 organisms of public health or food quality significance. Exclusion of 

 objectionable, foreign, and filthy material or origin must be assured. In 

 shellfish sanitation, special recognition should be given to the certification 

 program of the U.S. Public Health Service which has administered the 

 provisions for many years through the public health programs of the 

 individual states. In recent years the necessity of ({uality control require- 

 ments has increased sharply in relation to plant sanitation, bacteriological 

 standards for foods, and use of food additives. Federal, state, and munici- 



