The Effect of Temperature and Salinity on the Depuration of Hepatitis A Virus and Other Microbial Contaminants from the Eastern Oyster

Comparative studies were done to evaluate the elimination of hepatitis A virus (HAV), poliovirus 1, MS2 bacteriophage, Esherichia coli, and Streptococcus faecalis in experimentally contaminated Eastern oysters in a laboratory-scale depuration system. The effect of temperature (12, 18, and 25°C) and salinity (8, 18, and 28 ppt) on virus and bacteria depuration was studied. The oysters were contaminated with high levels of organisms in order to follow depuration over several orders of magnitude during several days of depuration. At each day of the depuration period, a sample of contaminated oysters was removed from the tanks and processed for bacteriological and virological analysis. The depuration system was maintained within the range of the environmental conditions required by the U.S. water quality depuration standards. HAV was not effectively depurated and was detected at generally higher levels than the other test organisms at all the conditions tested. Depuration rates were reduced at lower temperature and lower salinity. These results indicate that depuration may not be an effective means of eliminating HAV and other pathogens from contaminated oysters under some depurating conditions. KEY WORDS: hepatitis A virus (HAV), poliovirus 1, MS2 bacteriophage, Esherichia coli. Streptococcus faecalis, fecal coliform, depuration, bivalves, and oysters.Master of Science in Public Healt