If you Eat Raw Oysters, You Need To Know....
About 20 million American eat raw oysters. However, for some
people, eating raw oysters can cause serious illness or even
death. What causes this? How do you know if you are at risk?
What can you do about it?
The Cause: Vibrio Vulnificus
Vibrio vulnificus a bacterium that occurs naturally in marine
waters and is commonly found in Gulf of Mexico oysters. While
not a threat to most healthy people, Vibrio vulnificus can cause
sudden chills, fever, nausea, vomiting, blood poisoning, and
death within two days in people with certain medical conditions.
Forty percent of Vibrio vulnificus infections from raw oyster
consumption are fatal. The bacteria are not a result of
pollution, so, although oysters should always be obtained from
reputable sources, eating oysters from "clean" waters or in
reputable restaurants with high turnover does not provide
protection. Eating raw oysters with hot sauce or while drinking
alcohol does not kill the bacteria, either.
The Risk Factors
Certain health conditions put you at risk for serious illness or
death from Vibrio vulnificus infection. Some of these conditions
have no signs or symptoms so you may not know you are at risk.
Check with your doctor if you are unsure of your risk.
These conditions include:
- liver disease, either from excessive alcohol intake, viral
hepatitis or other causes
- hemochromatosis, an iron disorder
- diabetes
- stomach problems, including previous stomach surgery and low
stomach acid (for example, from antacid use)
- cancer
- immune disorders, including HIV infection
- long-term steroid use (as for asthma and arthritis).
If you are an older adult, you also may be at increased risk
because older people more often have these risk conditions than
younger people.
If you are or think you may be in any of these risk categories,
you should not eat raw oysters. However, because fully cooking
oysters completely kills the bacteria, you can continue to enjoy
oysters in many cooked preparations.
Drinking Alcoholic Beverages Regularly and Liver Disease
If you drink alcoholic beverages regularly, you may be at risk for
liver disease, and, as a result, at risk for serious illness or
death from raw oysters. Even drinking two to three drinks each
day can cause liver disease, which may have no symptoms. Liver
disease will put you at increased risk for Vibrio vulnificus
infection from raw oysters. The risk of death is almost 200
times greater in those with liver disease than those without
liver disease.
Oyster Safety: What You Can Do
At Restaurants
Order oysters fully cooked. Some states display notices for those
at risk. Use them as reminders of how to avoid illness.
Cooking at Home
In the Shell
- Boil live oysters in boiling water for 3 to 5 minutes after
shells open. Use small pots to boil or steam oysters. Do not
cook too many oysters in the same pot because the ones in the
middle may not get fully cooked. Discard any oysters that do not
open during cooking.
- Steam live oysters 4 to 9 minutes in a steamer that's already
steaming.
Shucked
- Boil or simmer for at least 3 minutes or until edges curl.
- Fry in oil for at least 3 minutes at 375° F.
- Broil 3 inches from heat for 3 minutes.
- Bake (as in Oysters Rockefeller) for 10 minutes at 450° F.
If you have additional questions or to order more copies of this
brochure, call the
FDA Seafood Hotline, (1-800) FDA-4010.
DEPARTMENT OF HEALTH AND HUMAN SERVICES
Public Health Service
Food and Drug Administration
DHHS PUBLICATION NO. (FDA) 95-2293, July 1995
Additional information on foodborne illness
Go BACK to the CFSAN/FDA food and consumer information page
Hypertext updated by dms, 12/15/96
