The microbial composition of Pacific oysters (Crassostrea gigas)
subjected to UV-treated seawater was determined by quantitative and
qualitative means. A total of 2,779 microorganisms were identified
from seawater and oysters during a 72 hour sampling period employing
a computer assisted replica-plating technique. UV treatment effectively eliminated coliforms and Pseudomonas Type I from seawater
but other gram-negative asporogenous rods were more resistant. The
microogranisms commonly found in oysters, whether subjected to UV-treated
seawater or not, were, in the order of predominance, Pseudomonas
Type III or IV, Vibrio/Pseudomonas Type II, Flavobacterium/
Cytophaga and Acinetobacter /Moraxella. The composition of
microbial flora in oysters remained relatively stable irrespective of
the microorganisms present in the seawater. A total of 18 presumptive
hemolytic vibrios were found in oysters but further confirmation
revealed two isolates to be Vibrio parahaemolyticas and the remainder Aeromonas species. Approximately 10 percent of the
microorganisms isolated from seawater and oysters were gram-positive
cocci and 14 to 23 percent of these were coagulase positive,
DNase positive, and (β-hemolytic on human blood agar. / Graduation date: 1971
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/26837 |
| Date | 11 December 1970 |
| Creators | Vasconcelos, George Joseph |
| Contributors | Lee, J. S. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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