Mycobacterium strain DP was isolated from marine coastal sediment and tested for its ability to oxidize cholesterol in Tween 80-cholesterol (2.59 mM) medium. Strain DP degraded cholesterol to 4-cholesten-3-one (cholestenone), 4-androsten-3,17-dione (AD), 1,4-androstadien-3,17-dione (ADD), testosterone, and 1-dehydrotestosterone (DHT). Cholesterol disappeared in about 4 days. Cholestenone, AD, testosterone, and DHT accumulations were transient with peak concentrations of 300, 600, 30 to 40, and 21 tLM. ADD production peaked after 6 days with a concentration of 1,100 ,uM. Peak ADD concentrations and production rates compared well with those reported for strain NRRL B3683 on cyclodextrin medium. Tween 80 medium was superior to finely dispersed cholesterol particles for both strains. In comparison, NRRL B3683 (patented for its ability to accumulate AD and ADD) on Tween 80 medium transiently accumulated more AD (-1,000 ,uM) than did strain DP, but ADD accumulations (200 ,uM) were significantly lower than those for strain DP. Strain DP could be adapted to grow on ADD, which was initially inhibitory at 3.25 mM. ADD-adapted strain DP cultures produced approximately four times as much DHT from ADD than unadapted cultures did from cholesterol, showing that additional manipulation might enhance testosterone production. We believe that ADD toxicity might account for the low ADD accumulations by NRRL B3683 in Tween 80 medium.

Aerobic, heterotropic microorganisms of Dungeness crab (Cancer magister) were isolated from raw crab, cooked crab, crab meats obtained during commercial processing, and from retail crab meat samples. Each microbial isolate was then identified to the genus level employing the revised replica plating procedure. Microbial groups most commonly isolated from crab meat were, in the order of predominance, Moraxella, Pseudomonas, Acinetobacter, Arthrobacter, Micrococcus, Flavobacterium-Cytophaga, and Bacillus sp. Proteus, Staphylococcus, yeasts, Vibrio, and Lactobacillus sp. were found less frequently in some samples. Distribution patterns of microbial flora in crab meat revealed the presence of three classes of microorganisms. Microorganisms that originated from the raw crab and gained predominance by growth during refrigerated storage were Moraxella, Pseudomonas, Acinetobacter, and Flavobacterium-Cytophaga sp. Those that originated from the crab but did not grow in meat were Arthrobacter and Bacillus sp. Micrococcus, Staphylococcus, and Proteus sp. were introduced during processing, but they did not grow in the refrigerated crab meat.

Four hundred fifty-five microbial isolates from seafoods were replicated on tryptone-peptone-yeast extract agar with 0.5% NaCl (TPE), trypticase soy agar with 3.0% NaCl (TSA), and plate count agar with no added NaCl (PCA). Daughter plates were incubated at 5, 25, 35, and 37 C, and colonies that developed on the plates were identified. At 25 C, 7% of TPE isolates failed to grow on PCA and 4% on TSA. The difference was mainly caused by Pseudomonas type III species, 24% of which failed to grow on PCA; Pseudomonas type II species, 13% of which failed on PCA; and Flavobacterium-Cutophaga species, 18% of which failed on TSA. Except for the reference mesophilic, cultures of Staphylococcus, Micrococcus, Escherichia coli, and Vibrio parahaemolyticus—which grew equally well at 25 and 35 C but failed to grow at 5 C—49% of colonies growing at 25 C failed to grow at 35 C, and 17% at 5 C. Microbial groups in order of sensitivity to 35 C were Arthrobacter, Pseudomonas, Moraxella, Micrococcus, Flavobacterium-Cytophaga, and Acinetobacter, with the respective growth failures at 35 C of 68, 51, 46, 42, 33, and 29%. Microbial groups that failed to grow at 5 C in the order of sensitivity were, Flavobacterium-Cutophaga, Acinetobacter, Arthrobacter, and Moraxella with respective growth failures of 40, 26, 12, and 9%.

Aerobic microbial flora, moisture, and NaCl contents of smoked salmon samples, obtained from retail outlets along the roast of the Pacific Northwest, were examined. The microbial loads ranged from 1.3 × 102 to 2.2 × 106. The moisture level were from 48 to 64%, and the water phase salts from 3.2 to 8.2. Regularly recoverable microorganisms in most samples were gram-positive cocci. They were either mostly staphylococci micrococci, depending on the sample. Bacillus, Pseudomonas, and yeasts were predominant in some samples. The gram-positive cocci were able to grow in 10 to 25% NaCl, but the majority of them did not multiply at 4 C and were readily inactivated by mild heat (D52C of 1.5 to 47.9 min).

Microorganisms associated with Pacific shrimp (Pandalus jordani) were isolated and identified. Those on the iced raw shrimp, which yielded an average count of 1.6 x 106, were predominantly Moraxella, Pseudomonas, Acinetobacter, Arthrobacter, and Flavobacterium-Cytophaga spp. The blanching and peeling reduced the microbial level to 3.3 x 104 and also selectively eliminated Moraxella spp. The microbial flora changed after each processing sequence, and the heat sensitivity and growth characteristics of the representative microbial groups suggested that the presence of Arthrobacter and Acinetobacter spp. in peeled shrimp may indicate inadequate cleaning of raw shrimp or a shorter blanching time. The presence of Moraxella and Flavobacterium-Cytophaga spp. would indicate the degree of secondary contamination, and the presence of Pseudomonas spp. would indicate the shelf-age of the processed shrimp.