Depuration:
depuration of the harvested bivalves in an approved depuration center (depuration is the reduction of microorganisms to a level acceptable for human consumption by the process of holding live bivalve mollusks for a period of time under approved, controlled conditions in natural or artificial seawater suitable for the process, which may be treated or untreated); [ScienceDirect]
Noted in “An inside look at oysters – and how to enjoy them safely,” Sam Wong, NewScientist (20 November 2021):
As filter-feeders, oysters can pick up pathogens lurking in the water. To reduce this risk, they are usually kept in clean water for 42 hours after harvesting in the UK, a process called depuration.
Sadly, this isn’t completely effective – particularly with respect to norovirus, one of the most common causes of gastroenteritis. A 2017 report found that between 100 and 1000 copies of the norovirus genome may remain in each gram of oyster tissue after depuration. Just 10 copies are thought to constitute an infectious dose.
