texture often dropped farther than the taste 

 ratings for these samples. Evidently, the 

 method of packaging as well as the length of 

 the storage period significantly affects the qual- 

 ity of samples held at 0° F for up to 8 months. 



Comparison of Two Packaging 



Methods 



It was generally noted that the samples which 

 had been packaged in a vacuum-sealed pouch 

 (laminated polyethylene-aluminum foil-mylar) 

 rated higher than samples which had been 

 packaged in unsealed polyethylene bags under 

 atmospheric pressure. In samples stored at 

 — 20° F, this difference was more pronounced 

 in the odor ratings than in the taste ratings. 

 In samples stored at 0° F, this difference be- 

 came obvious in the taste ratings after much 

 shorter storage periods. 



Comparison of Types of Blue Crab 



Meat 



In evaluating the results of the taste-panel 

 evaluations (Tables I-l and 1-2), flake and 

 lump meat samples have been considered on 

 virtually synonomous terms. Lump meat is 

 often regarded as a premium grade of flake 

 meat in the trade. The freezing and storage 

 characteristics of both types of meat appear 

 to be reasonably similar. On the other hand, 

 claw meat is considered a lower quality meat 

 even when fresh since it comes from a muscle 

 tissue which has a different physiological 

 function. Thus, the poorer ratings given for 

 the few frozen-stored claw meat samples tested 

 (Table I-l) are not surprising. The taste- 

 panel evaluations did not reveal any consistently 

 significant difference that could be related to 

 the low-salinity waters of the Chesapeake Bay 

 and the high-salinity waters off the Virginia 

 Coast. This conclusion may surprise some 

 gourmets who are partial to locally caught blue 

 crabs but the origins of this partiality are spec- 

 ulative. 



SUMMARY AND CONCLUSIONS 



The results of this investigation show that 

 rapid freezing, storage below 0° F, and vac- 



uum-packaging extend the shelf life of blue 

 crab meat. Quick-freezing methods (immer- 

 sion or spraying using Freon 12 or low-temper- 

 ature nitrogen) were superior to slow-freezing 

 methods (freezing time more than 30 min). 

 For example, after 8 months of storage at 

 — 20° F, quick-frozen, vacuum-packed, blue 

 crab meat was highly acceptable when com- 

 pared with fresh, refrigerated meat. At 0° F 

 storage temperature, a noticeable drop in qual- 

 ity occurred during storage, especially if the 

 product was not vacuum-packed. However, 

 vacuum-packed frozen crab meat of high initial 

 quality can be stored at 0° F for at least 8 

 months and still be comparable in quality to 

 heat-pasteurized crab meat that has been stored 

 at 34° F for the same time. 



The rate of freezing blue crab meat has a 

 significant effect on preserving its desirable 

 qualities. Using spraying or immersion tech- 

 niques based on Freon 12, freezing was accom- 

 plished in about 1 min and resulted in a product 

 of very acceptable quality after storage and 

 thawing. Slightly longer freezing rates were 

 involved in some of the cryogenic nitrogen 

 freezing methods. Although these freezing 

 rates were less than 3 min, they resulted in 

 products with a slightly lower acceptability. 

 Even without considering the detrimental ef- 

 fects of slow freezing (30 min or more), it is 

 obvious that the quality of frozen-stored blue 

 crab meat is directly related to the rapidity of 

 freezing it. 



To extend the shelf life of frozen blue crab 

 meat, it would be advisable to store it below 

 0°F, preferably as low as — 20° F. Storage 

 temperatures below — 20° F offer further im- 

 provement in its storage stability but they 

 are usually not as economically feasible as the 

 higher temperatures. At 0° F storage temper- 

 ature, a noticeable drop in quality can occur 

 during storage, especially if proper attention 

 is not given to considerations such as using only 

 crab meat of high initial quality, quick freezing, 

 vacuum packaging, and minimum storage per- 

 iods. 



The method of packaging had a noticeable in- 

 fluence on the storage stability of frozen crab 

 meat. At 0° F storage temperature, vacuum 

 packaging in a heat-sealed polyethylene-alumi- 

 num foil-mylar pouch resulted in a considerably 



