Survival of Vibrio vulnificus and Escherichia coli in artificially and naturally infected oyster (Crassostrea virginica) tissues during storage in spray- and immersion-type live holding systems

Live holding systems are used as temporary storage facilities for shellfish. The potential for mishandling of shellfish stored in these systems is high. The objective of the project was to examine the effects of storing oysters in a spray and an immersion systems on the survival of Escherichia coli and Vibrio vulnificus within the oysters. The effects of physiological stress imposed on oysters, as a result of interstate shipping, were examined by monitoring the level of E. coli in these oysters during storage in a spray tank. The survival rates of naturally-present E. coli and V. vulnificus in oysters were also observed. The research examined the distribution of artificially- and naturally-present V. vulnificus in oyster tissues during storage in an immersion system. There was no significant difference (p = 0.12) in the artificially-inoculated bacterial population of oysters after 120 hr of storage in a spray live holding tank. The level of E. coli in oysters which were subject to physiological stress did not change significantly (p = 0.30) after 96 hr in the spray tank. Naturally-present E. coli and V. vulnificus in oysters at harvest persisted during the 72 hr storage in the spray tank. V. vulnificus was loosely associated with mucus on the surfaces of the adductor and the mantle tissues in artificially-inoculated oysters. As a result, the bacterial level was reduced on these surfaces during the 72 hr of depuration. V. vulnificus on the gills and the digestive system of artificially-inoculated oysters may become entrapped in cilia and mucus. There was no significant reduction in the bacterial population on the gills (p = 0.11) and on the digestive system (p =0.21). There was no significant difference in the population of V. vulnificus in the adductor muscle (p = 0.37), the mantle (p = 0.16), the gills (p = 0.5), and the digestive system (p = 0.5) of summer oysters naturally-infected with the bacterium. It seems unlikely that depuration of V. vulnificus from oysters naturally harboring the bacterium may be effective.

Name thesis:degree_name

Ph. D.

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Food Science and Technology

Department dc:contributor.department

Food Science and Technology

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

1992

Author dc:creator

• Colby, Jhung-Won

Chair dc:contributor.committeechair

• Flick, George J. Jr.

Committee members dc:contributor.committeemember

• Boardman, Gregory D.
• Graham, Paul P.
• Krieg, Noel R.
• Pierson, Merle D.

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

etd-06192006-125717

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/38623