State warns warm weather raises raw oyster risks


Puget Sound-NASAWashington State Department of Health warns that warm weather increases risk of food poisoning from shellfish taken from local waters:

Olympia – The warm air and water during summer can lead to bacteria that can grow in oysters — and people who love to eat raw oysters could get sick from them.

The Department of Health urges everyone who gathers shellfish from Washington waters to take a few basic steps to stay healthy while eating fresh shellfish during the summer season.

Warm temperatures are ideal for the natural bacteria known as Vibrio parahaemolyticus to multiply. Eating raw or undercooked shellfish – especially oysters containing vibrio bacteria – can make people sick.

“We have great shellfish in Washington and we want people to enjoy them – safely,” said Jerrod Davis, director of the agency’s Office of Shellfish and Water Protection. “By following some simple safety tips, including cooking oysters thoroughly, people can stay healthy this summer.”

People who dig or gather shellfish can protect themselves from illness by:

  • Know shellfish harvesting conditions before they go: call 1-800-562-5632 or check our clickable maps on the shellfish safety webpage to see if there are any beach closures for vibrio, biotoxins, or pollution.
  • Harvest shellfish from the beach as soon as possible after the tide recedes rather than waiting until after they’ve been exposed to the air for a long time.
  • Refrigerate or put shellfish on ice immediately after harvesting and keep them cold until they’re prepared and eaten.

Cooking shellfish just until the shells open is not enough to kill vibrio bacteria; shellfish should be cooked to an internal temperature of 145 degrees Fahrenheit for at least 15 seconds. Generally, keep cooking three to five minutes after the shells open when boiling, and four to nine minutes when steaming shellfish.

If you  eat undercooked or raw shellfish, symptoms of vibriosis – the illness caused by vibrio bacteria – usually appear within 12-24 hours of eating infected shellfish. Symptoms may include diarrhea, stomach cramps, nausea, vomiting, headache, fever, and chills; they normally last from two to seven days.

For people with lowered immunity or chronic liver disease, vibriosis can be life-threatening. Antibiotic treatments, cancer therapies, and medications to treat heart conditions, diabetes, and acid reflux can cause a higher risk for serious illness. People who undergo these treatments or take these medications should never eat raw or undercooked shellfish.

State officials warn that cooking shellfish doesn’t prevent all illnesses. Biotoxins found in Washington waters aren’t destroyed by cooking. People who gather their own shellfish should always check the Shellfish Safety Hotline at 1-800-562-5632 or check the clickable map website to learn about closures or health warnings.