Oysters – Tasty but Risky

I just wanted to pass along a little information I received recently. Apparently six people became ill with Vibrio parahaemolytics from raw oyster consumption in the source state, Washington. The raw oysters were distributed to 11 other states and five countries (Canada, Indonesia, Hong Kong, Singapore and Thailand). No other illnesses have been reported. Guidance for safe consumer consumption of fully cooked oysters is included.

FDA Expands Warning on Eating Raw Oysters
Media Inquiries: Michael Herndon, 301-827-6242
Consumer Inquiries: 888-INFO-FDA

Additional Growing Area Linked to Illness Outbreaks

The U.S. Food and Drug Administration is warning consumers not to eat raw oysters harvested from an additional part (growing area 5) of the southern tip of Hood Canal in Washington state due to a foodborne illness outbreak caused by Vibrio parahaemolyticus bacteria. This follows an earlier outbreak and August 10 warning about oysters harvested from growing area 6 of Hood Canal.

Symptoms of the illness, vibriosis, include watery diarrhea, often with abdominal cramping, nausea, vomiting, fever, and chills. Usually these symptoms occur within 24 hours of ingestion and last no more than three days. Severe disease is rare and occurs most commonly in people with weakened immune systems. Those who believe they have experienced these symptoms after consuming raw oysters should consult their health care provider and contact their local health department.

Raw oysters harvested from growing area 5 in Hood Canal from July 31 through August 20, 2007 have caused at least six people to become ill in Washington state. To date, records indicate that raw oysters from the area were distributed to Arizona, California, Colorado, Delaware, Florida, Idaho, Minnesota, New York, Oregon, Pennsylvania, Utah, Washington state, British Columbia (Canada), Bali (Indonesia), Hong Kong, Singapore, and Thailand.

The Washington State Department of Health has closed the growing area associated with the illness and has asked commercial oyster harvesters and dealers who obtained oysters from this area to recall them.

Consumers who have recently purchased oysters should check with the place of purchase and ask if they were harvested from the affected growing areas. The recall involves both shucked oysters and oyster in the shell (shell stock oysters).

Those with weakened immune systems, including people affected by HIV/AIDS, chronic alcohol abuse, liver, stomach, or blood disorders, cancer, diabetes, or kidney disease, should avoid eating raw oysters, regardless of where they are harvested.

FDA advises that consumers can continue to enjoy oysters in many cooked preparations by doing the following:

At Restaurants and other Foodservice Establishments:

· Order oysters fully cooked.

In the Shell:

· Purchase oysters with the shells closed

· Throw away any oysters with shells already opened.

· Never allow raw seafood to come into contact with cooked food.

· Boil or steam the oysters:

· Boil oysters until the shells open. Once shells open, boil for an additional three to five minutes.

· To steam—add oysters to water that is already steaming and cook live oysters until the shells open, once open steam for another four to nine minutes.

· Use smaller pots to boil or steam oysters. Using larger pots, or cooking too many oysters at one time,

· Discard any oysters that do not open during cooking.

Shucked Oysters:

· Never allow raw seafood to come into contact with cooked food.

· Cook the oysters in one of the following ways:

· Boil or simmer shucked oysters for at least three minutes or until the edges curl.

· Fry at 375° F for at least three minutes.

· Broil three inches from heat for three minutes.

· Bake at 450° F for 10 minutes.

For more information:
Hood canal oyster area closed — second closure due to illness outbreak – a news release from the Washington State Department of Health

FDA’s discussion on V. parahaemolyticus is in the “Bad Bug Book.”


A description about V. parahaemolytics from the Centers for Disease Control (CDC)


CDC/MMWR gives a list of Morbidity and Mortality Weekly Reports at CDC relating to V. parahaemolyticus. The date shown is the date the item was posted on the Web, not the date of the MMWR. The summary statement shown are the initial words of the overall document. The specific article of interest may be just one article or item within the overall report.


NIH/PubMed (a service of the US National Library of Medicine and National Institutes of Health) provides a list of research abstracts contained in the National Library of Medicine’s MEDLINE database for V. parahaemolyticus..


AGRICOLA will provide a list of research abstracts contained in the National Agricultural Library database on V. parahaemolyticus.


The Seafood HACCP Alliance Compendium and the FDA’s Hazards Guide provide information on how to develop HACCP plans to control for this biological hazard.

http://seafood.ucdavis.edu/haccp/compendium/chapt20.htm – HACCP Alliance Compendium

http://www.cfsan.fda.gov/~comm/haccp4d.html – FDA’s Hazards Guide (note the FDA is expecting to release a new version possibly by the end of this year)

US FDA Food Code recommendations for cooking fish (includes molluscan shellfish as defined by the FDA seafood HACCP regulation 21 CFR 123 part 123.3(d) http://www.cfsan.fda.gov/~lrd/searule3.html ) is 145F/63C for 15 sec.; 155F/68C for 15 sec for comminuted fish; and 165F/74C or above for 15 sec for stuffed fish.

http://www.cfsan.fda.gov/~acrobat/fc05-3.pdf – see 3-401.11 Raw Animal Foods (starts on p. 72)

Latest posts by Warren Ransom (see all)

Pin It on Pinterest

Share This