Pacific shrimp (Pandalus jordani) was washed repeatedly and the
eluted bacteria were enumerated and identified. Selected isolates
were tested for their adhesive properties.
Washing reduced the microbial load by 3.84 to 42.04%. The bacteria
which most resisted wash-off were Staphylococcus and Pseudomonas
spp. The easiest to wash off was Flavobacterium spp. In higher-count
samples, Moraxella and/or Lactobacillus spp. washed off readily, but
they still constituted large proportions of the residual bacteria on
shrimp.
Adhesiveness, measured by hydrophobic interaction with octane,
showed 43.3% change in absorbance by Staphylococcus spp., followed by
21.5% by Moraxella spp., and Arthrobacter spp. at 13.5%. Pseudomonas
spp. showed only 5.7% change in absorption.
Attachment, measured by hanging glass cover slips in broth, however,
showed Pseudomonas and Staphylococcus spp. to have the greatest
ability to adhere, with 0.47 and 0.46% attachment, respectively.
Moraxella spp. showed the least ability to adhere to glass (.02%), followed by Lactobacil lus spp. at 0.11%. Arthrobacter and Flavobacterium
spp. adhered at 0.30 and 0.37% levels, respectively.
Attachment of Pseudomonas spp. to glass was the least affected
by media composition, temperature, or presence of a surface-active
agent (sodium hexametaphosphate).
Staphylococcus spp., on the other hand, attached most strongly
under optimum growth conditions but were most affected by varying
growth conditions, temperature, and presence of a metabolic inhibitor
(sodium hexametaphosphate).
This indicates that the adhesive ability of Staphylococcus spp.
is directly related to its metabolic activity, while Pseudomonas spp.
is less sensitive to changes in metabolism and may depend on motility
for adhesion.
Bacteria that could adhere strongly on solid surfaces (Pseudomonas
and Staphylococcus spp.) tend to be found in greater proportions
and, hence, contribute more to the spoilage of shrimp. / Graduation date: 1983
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/27198 |
| Date | 04 January 1983 |
| Creators | Smith, John B. |
| Contributors | Lee, Jong S. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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