are also scored.) These marks are not judg- 

 ments of the panels' preferences, but assess- 

 ments of how severe is the scorch, how light or 

 dark is the color, and so on. This method has 

 been experimented with and the techniques re- 

 fined until scoring is reasonably consistent, al- 

 though all subjective judgments of this kind 

 are somewhat inconsistent. It should be noted 

 that "workmanship," that is, qualities such as 

 incomplete removal of skin or bone, are primar- 

 ily measures of the canner's efficiency and so 

 are not included in the panel's judgments. 



Taste panels have their limitations, and it 

 would be preferable to use instruments to 

 measure quality for all purposes except accept- 

 ance tests, which can only be made with people. 

 Such an approach, if successful, could be more 

 precise and repeatable than a panel. It would 

 eliminate the need for selection and training 

 of personnel, and the inevitable person-to-per- 

 son, day-to-day, even year-to-year variation 

 which trained tasters show. Quality measure- 

 ment by instruments has been developed suc- 

 cessfully for some foods, although it is not pos- 

 sible to measure all the quality attributes in 

 food with the same reliability. Methods for 

 color and texture have been developed for many 

 products, and it seemed likely at the outset of 

 the program that they could be applied to tuna. 

 Figure 1 shows that relation between panel 

 color scores on canned tuna and reflectance 

 measurements measured with a suitable instru- 

 ment (Color Master) on the samples. Dr. An- 



05 



UJ 



o 

 o 



< 



Q. 



10 20 30 40 



COLOR MASTER VALUES, CLE. UNITS 



Figure 1. — A comparison of color master reflectance 

 values in CLE. units to a taste panel's ratings of 

 canned tuna. 



gela Little, a specialist in this area at the Uni- 

 versity of California, Berkeley, has investigated 

 such objective tests that may be adaptable for 

 use with canned tuna. A fairly simple method 

 was developed which measured color with great- 

 er precision and consistency than could be 

 shown by a taste panel (Little et al., 1969) . De- 

 velopment of methods for the measurement of 

 texture is also showing some promise, although 

 these are likely to be more complicated, since 

 texture is made up of several factors. Such 

 methods would be helpful for research work 

 and might also be used in routine quality con- 

 trol. Objective measurements of odor and 

 flavor in foods generally have had a very lim- 

 ited success so far, and there is no present 

 prospect of their useful application to canned 

 tuna. However, there are indications that odor 

 and flavor levels may be related to other pro- 

 perties which can be measured and which would 

 enable their indirect assessment. 



Hence, it seems likely that in the not too 

 distant future we may be able to dispense with 

 the taste panel for some purposes and use the 

 more precise — although possibly rather slower 

 — methods of objective measurement for qual- 

 ity. While this approach will give sound and 

 useful measures of such qualities as color and 

 flavor, the inability to relate these qualities 

 more closely to consumer preferences is a seri- 

 ous weakness. In other words, it can be de- 

 termined how light or dark a sample may ap- 

 pear and how much off'-flavor it may have, but 

 it has to be determined by a national consumer 

 survey as to how this influences the customer's 

 buying judgment. Present restrictions upon 

 the use of surveys by Federal agencies prevents 

 their engaging in consumer surveys by which 

 this relationship may be directly determined, 

 and we must rely upon the indirect evidence 

 for the time being. 



Refrigeration of Tuna: Chilling 

 and Freezing 



The refrigeration requirements of the U.S. 

 tuna fishery are unique among fisheries. The 

 variable and often very high catch rate of fish, 

 the high tropical water temperatures, the long 

 distances from the canneries, and the consider- 

 able diff'erences in size of the fish pose unusual 



