 The seawater that the oysters were originally farmed in does not remain in the oyster, since the water used for depuration must be fully sterilized, plus the depuration facility would not necessarily be located near the farming location.Depuration of oysters can remove moderate levels of contamination of most bacterial indicators and pathogens.Well-known contaminants include "Vibrio parahaemolyticus", a temperature-sensitive bacterium found in seawater animals, and "Escherichia coli", a bacterium found in coastal waters near highly populated cities having sewage systems discharging waste nearby, or in the presence of agricultural discharges.