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Abstracts
Workgroup: Public Health and Processing
Reduction of Red Tide Toxin in Clams and Oysters by Ozone Purification and Relaying
Principal Investigator(s):
Richard Pierce, Marine Laboratory, 1600 City Island Park, Sarasota, FL; and University of Florida, Department of Food Science and Human Nutrition, Gainesville, FL, rich@marinelab.sarasota.fl.us
Co-Investigator(s):
Michael Henry, Mote Marine Laboratory, 1600 City Island Park, Sarasota, FL.
Gary E. Rodrick, University of Florida, Department of Food Science and Human Nutrition, Gainesville, FL
Gary E. Rodrick, University of Florida, Department of Food Science and Human Nutrition, Gainesville, FL
Funding Period: October 1, 1998-August 31, 2001
A study of the accumulation and purification of harmful algal biotoxins in the clam Mericenaria mericenaria and the Eastern oyster Crassostrea virginica was initiated to investigate the use of ozone as a means to enhance the natural purification of toxins. Clams were exposed to viable cell of the Florida red tide organism, Gymnodinium breve (5 x 106 cells/clam/day) for 9 days. Following exposure, the clams were divided into groups of natural relay vs. ozone purification. The concentration of brevetoxins (PbTx-2 and PbTx-3) in the exposure water and clam tissue was monitored by HPLC-UV analysis and by receptor-binding assay. The amount of total PbTx-2 and PbTx-3 in the original culture prior to dilution for clam exposure and brevetoxin concentration in the effluent water after exposure clams show that the clams were exposed to appropriate levels during the study. These results show the presence of brevetoxins in the spiked samples and a definite accumulation of active toxins after 10 days of exposure. After 3 days of ozone purification, the treated clams exhibited a 50% drip in the brevetoxin activity level, whereas the non-ozone treated clams exhibited 38% drop in the 10 day exposure level. Relaying the red tide contaminated clams to clean seawater for 15 days removed (100%) toxin activity when compared to non-relayed controls.
IMPACTS and/or BENEFITS:
This research is responsible for the development of viable methods (ozone depuration and relaying to clean waters) to assist the both clam and oyster farmers during a red tide outbreak. This research has demonstrated that relaying oysters and clams to clean seawater areas for 14 days resulted in the reduction of red tide toxin to below acceptable market and regulatory levels in the clam and oysters meats.
PROJECT PUBLICATIONS:
Richard Pierce, Michael Henry, and Gary Rodrick. Reduction of Red Tide Toxin in Clams and Oysters by Ozone Purification and Relaying. Published in the Proceedings of the International Molluscan Shellfish Safety Conference.
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