OSU makes oysters safer to eat

oysters on a plate
Oregon producers farmed $3 million of oysters in 2012. (Photo by Lynn Ketchum.)

Improved purification method keeps oysters alive and doesn't sacrifice taste or texture

Each year in the U.S., more than 45,000 cases of the illness are linked to seafood, particularly raw oysters. To make them safer to eat, OSU has improved an old method of cleansing their systems.

The method that OSU improved is called depuration, in which oysters are placed in tanks of clean seawater at room temperature. The shellfish expel bacteria that's in them into the water, which is then cleaned by a manmade filter and sterilized with ultraviolet light. But under this old method, more than 10 percent of a bacteria called Vibrio parahaemolyticus still remain. This bacteria can cause gastroenteritis, an infection marked by severe abdominal pain, vomiting and diarrhea.

Seeking a better alternative, OSU chilled the water to between 45 and 55 degrees in addition to using the UV light. This eliminated 99.9 percent of the bacteria, the oysters stayed alive, and their taste and texture were not altered. The system is cheap to build and uses less electricity than methods that rely on freezers, heat, pressurization and radiation.

Watch how the process works in this video.

Source: Yi-Cheng Su, OSU professor of seafood microbiology and safety; OSU Extension Service's 2012 Oregon County and State Agricultural Estimates; the U.S. Centers for Disease Control and Prevention.

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