page_title: Depuration
section_title: History
hierarchical_section_title: Depuration / History
caption_attribution_description: Oysters filter water in a depuration tank at Oregon State University's Seafood Laboratory in Astoria. As the oysters filter the water, they excrete harmful bacteria from their digestive tracts and become safe to eat. (Photo by Lynn Ketchum.) FULL STORY: extension.oregonstate.edu/news/release/2013/03/osu-makes-...
context_page_description: Depuration of seafood is the process by which marine or freshwater animals are placed into a clean water environment for a period of time to allow purging of biological contaminants and physical impurities. The most common subjects of depuration are such bivalves as oysters, clams, and mussels.
context_section_description: Most research and publications focus primarily on the depuration of seafood rather than freshwater animals. The commonly defined depuration process has been practiced since the 1800s originating as a method to prevent typhoid fever (via Salmonella enterica subsp. enterica, serovar Typhi) and other illnesses attributed to polluted shellfish being consumed. As coastal seawater became increasingly contaminated with sewage-borne bacteria, early research investigated the use of disgorging tanks. Today, modern seafood depuration is performed in segregated physical tanks using treated seawater that is sterilised either by way of chlorine, ultraviolet, or ozone.
  Seafood depuration is legislated or regulated in many countries, including the United States, EU members such as France, Ireland, and Italy, and Japan. Oversight is managed by internationally recognised agencies, for example, in the United States, the National Shellfish Sanitation Program (NSSP) administered by the Interstate Shellfish Sanitation Conference sets guidelines on depuration and is recognised by the U.S. Food and Drug Administration. In Canada, the Canadian Food Inspection Agency (CFIA), Fisheries and Oceans Canada (DFO) and Environment and Climate Change Canada (ECCC) actively compile the manual for the Canadian Shellfish Sanitation Program (CSSP). The Codex Alimentarius, which is overseen by the World Health Organization (WHO) and Food and Agriculture Organisation of the United Nations (FAO), both recognises and encourages the application of seafood depuration.
  According to the FAO in December 2006, France had 1422 depuration facilities, Italy had 144, Japan had over 1,000. The long history of the depuration process which expands across many countries and is recognised by international agencies is contrasted by the scarce or nonexistent data in the commercial space of the seafood industry. In a majority formal research, publications and governmental regulations, depuration is approached in the form of "public protection" and not in the form of "public awareness". One research study attempts to link the benefits of consumer awareness of shellfish depuration and found that surveyed restaurants were reluctant to sell depurated seafood. Whereas in the same study, consumers surveyed indicated they were prepared to pay a premium for depurated oysters. However, the willingness to pay a premium was expressed after the consumer was informed about depuration and depurated seafood indicating the average consumer was unaware about the depuration process.
caption: Oysters in a depuration tank at a laboratory
exif: {"Image Make": "NIKON CORPORATION", "Image Model": "NIKON D2X", "Image Orientation": "Horizontal (normal)", "Image XResolution": "240", "Image YResolution": "240", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "Adobe Photoshop CS5 Macintosh", "Image DateTime": "2010:12:07 00:00:00", "Image Artist": "Lynn Ketchum", "Image Copyright": "\u00a9 2009 Oregon State University", "Image ExifOffset": "288", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "954", "Thumbnail JPEGInterchangeFormatLength": "4874", "EXIF ExposureTime": "1/60", "EXIF FNumber": "20", "EXIF ExposureProgram": "Manual", "EXIF ISOSpeedRatings": "100", "EXIF ExifVersion": "0221", "EXIF DateTimeOriginal": "2009:05:14 14:07:47", "EXIF DateTimeDigitized": "2009:05:14 14:07:47", "EXIF ShutterSpeedValue": "5906891/1000000", "EXIF ApertureValue": "540241/62500", "EXIF ExposureBiasValue": "0", "EXIF MaxApertureValue": "4", "EXIF SubjectDistance": "3/10", "EXIF MeteringMode": "Pattern", "EXIF LightSource": "Fine weather", "EXIF Flash": "Flash did not fire", "EXIF FocalLength": "17", "EXIF SubSecTime": "00", "EXIF SubSecTimeOriginal": "00", "EXIF SubSecTimeDigitized": "00", "EXIF ColorSpace": "Uncalibrated", "EXIF ExifImageWidth": "4288", "EXIF ExifImageLength": "2848", "EXIF SensingMethod": "One-chip color area", "EXIF FileSource": "Digital Camera", "EXIF SceneType": "Directly Photographed", "EXIF CVAPattern": "[2, 0, 2, 0, 0, 1, 1, 2]", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Manual Exposure", "EXIF WhiteBalance": "Manual", "EXIF DigitalZoomRatio": "1", "EXIF FocalLengthIn35mmFilm": "25", "EXIF SceneCaptureType": "Standard", "EXIF GainControl": "None", "EXIF Contrast": "Normal", "EXIF Saturation": "Normal", "EXIF Sharpness": "Normal", "EXIF SubjectDistanceRange": "0"}