26 



and the parasite's life cycle usually are -es- 

 sential. The university research was large- 

 ly supported by BCF contracts. 



Chinese A-Blasts Affect Oysters 



Studies at BCF's Radiobiological Labora- 

 tory at Beaufort, N.C., have detected radio- 

 activity in oysters caused by the Chinese 

 nuclear explosions. The findings result from 

 a program to study marine organisms that 

 have accumulated radioactive materials. Sev- 

 eral common marine invertebrate species in 

 the Beaufort area serve as biological indica- 

 tors for various types of radiation pollution. 



Fallout radioactivity from Red China's 

 second nuclear bomb test on May 26, 1965, 

 was detected in the oyster, Crassostrea vir - 

 ginica . Prior to this blast, radioisotopes with 

 relatively long active periods (about 1 year) - - 

 ruthenium 106, zinc 65, manganese 54, and 

 potassium 40 --were found in oyster tissue. 

 Eleven days after the blast, additional radio- 

 nuclides in the oysters included: cerium 141, 

 ruthenium 103, zirconium 95 -niobium 95, 

 and barium 140-lanthanum 140. 



These short-lived radioisotopes showed 

 that increased radioactivity was due to fresh 

 fallout. Lesser amounts of fresh fallout were 

 detected in marine organisms after the first 

 and third tests. Extremely sensitive detect- 

 ing equipment measured the radioactivity, 

 which was far below dangerous levels for 

 man. Apparently, the organisms lose accum- 

 ulated radioactivity quite rapidly: fresh fall- 

 out is detectable in samples for only a few 

 weeks after each test. 



I 



Analyze King Crab Data 



The length frequencies of male king crab 

 caught during the trawl survey by the BCF's 

 chartered vessel "Sonny Boy" in the Bering 

 Sea have been completed. The catch was 

 dominated by noncommercial size crab --less 

 than 125 mm. carapace length. The most 

 abundant group of commercial size crab oc- 

 curred between 125 mm. and 140 mm. The 

 researchers have nearly completed compar- 

 ing the 1966 length frequencies with those 

 collected from 1957 to 1961. 



Combine Heat and Irradiation to 

 Pasteurize Dungeness Crab Meat 



The Seattle Technological Laboratory in- 

 itiated a study of the feasibility of combining 

 heat pasteurization and irradiation pasteuri- 

 zation to extend the refrigerated shelf life of 

 high-quality, fresh, Dungeness crab meat. 

 Previous tests indicated that Dungeness crab 

 meat can be successfully heat -pasteurized by 

 the process used in the blue crab industry. 



The scientists hope that by combining low- 

 dose irradiation (less than 0.2 megarad) and 

 mild heat treatment (180° F.) storage life can 

 be increased significantly- -and without pro- 

 ducing the adverse odor and flavor changes 

 that accompany either higher irradiation doses 

 or prolonged heat treatment above 180° F, In 

 a 2 -week test period, with storage at 34° F., 

 two groups of samples were of good quality. 

 However, the taste panel preferred the sample 

 irradiated at 0.2 megarad followed by heat 

 pasteurization. 



Conduct Time-Temperature Studies 

 of Salmonella in Fish Meal 



The College Park and Pascagoula Techno- 

 logical Laboratories are cooperating in a 

 time -temperature study to determine the 

 process requirements. for consistently pro- 

 ducing a meal free of salmonella. The wide- 

 spread incidence of salmonellosis and the in- 

 crimination of fish meal as a carrier of the 

 causative organism inspired the study. Fol- 

 lowing various time -temperature treatments, 

 the meals were submitted to College Park for 

 nutritive value assessments. 



Determinations of thermal destruction were 

 made on several meals contaminated with a 

 mixture of 5 salmonella strains. The heat 

 treatment ranged from 150° F. for 60 min- 

 utes to 230° F. for a few minutes. Nutritive 

 value determinations revealed that no signifi- 

 cant damage was caused by the various heat 

 treatments required to destroy all salmonella 

 organisms. 



