The Real Risks of Eating Oysters

I often hear from people who won't even try oysters because they are afraid they will get sick or even die. Yes, you can become seriously ill from eating contaminated oysters, much like you can become ill from eating spinach with Listeria or beef with e coli. But the actual chance of getting ill from oysters far outweighs the perception that you will get sick. In an effort to find out what the real risk is for getting sick from oysters, Oyster Stew turned to none other than the Federal Drug Administration* - charged with protecting the American food supply - to help separate myth from reality. 

COMMON OYSTER MYTHS

MYTH 1: Eating raw oysters is safe if you drown them in hot sauce, which kills everything.

Fact: The active ingredients in hot sauce have no more effect on harmful bacteria than plain water. Nothing but prolonged exposure to heat at a high enough temperature will kill bacteria.

MYTH 2: Avoid oysters from polluted waters and you'll be fine.

Fact: Vibrio vulnificus in oysters has nothing to do with pollution. Rather these bacteria thrive naturally in warm coastal areas (such as the Gulf of Mexico) where oysters live. 

MYTH 3: An experienced oyster lover can tell a good oyster from a bad one.

Fact: Vibrio vulnificus can't be seen, smelled, or even tasted. Don't rely on your senses to determine if an oyster is safe.

MYTH 4: Alcohol kills harmful bacteria.

Fact: Alcohol may impair your good judgment, but it doesn't destroy harmful bacteria. In fact, people who drink alcoholic beverages (including beer and wine) regularly may be at risk for liver disease, and, as a result, at risk for serious illness or death from consuming raw oysters. 

MYTH 5: Just a few oysters can't hurt you.

Fact: Roberta Hammond, Ph.D, the Food and Waterborne Disease Coordinator for Florida, cites a case where a fatality caused by Vibrio vulnificus occurred after eating only three oysters. The seriousness of any case depends on many factors, including how much bacteria is ingested and the person's underlying health conditions.

MYTH 6: Avoid raw oysters in months without the letter "R" and you'll be safe.

Fact: While presence of Vibrio vulnificus bacteria is higher in warmer months, according to the Department of Health and Human Service's Centers for Disease Control and Prevention (CDC), a full 40 percent of cases occur during colder months from September through April.

MYTH 7: Raw oysters will cure a hangover.

Fact: There is no scientific evidence that this commonly held belief is true.

So oysters can't cure hangovers. We can live with that. But can oysters actually make us sick? Back to the FDA...

A SHORT Q & A WITH THE FDA:

How can oysters make people sick?

Raw oysters contaminated with Vibrio vulnificus can be life threatening, even fatal when eaten by someone with liver disease, diabetes or a weakened immune system. About 15 people a year die from the virus.

How do you know if you have a Vibrio vulnificus infection?

While not potentially life-threatening to most healthy people, symptoms of Vibrio vulnificus infection may occur within 24 to 48 hours of ingestion and may include sudden chills, fever, nausea, vomiting, diarrhea, shock and skin lesions. In people with certain medical conditions such as cancer, diabetes or liver disease death can occur within two days. Anyone showing signs of any these symptoms after eating raw oysters should seek medical attention immediately.

Are some people more at risk for becoming ill or dying from Vibrio vulnificus?

Certain health conditions put people at high risk for serious illness or death from V. vulnificus infections. Some of these health conditions may be present without any symptoms so people may not know they are at risk. Individuals should check with their doctors if they are unsure of their risk. Vibrio vulnificus infections in high-risk individuals have a 50 percent fatality rate.

These conditions include:

• Liver disease (from hepatitis, cirrhosis, alcoholism, or cancer)
• Iron overload disease (hemochromatosis)
• Diabetes
• Cancer (including lymphomas, leukemia, Hodgkin's disease)
• Stomach disorders
• Or any illness or medical treatment that weakens the body's immune system, including HIV infection

What if I really want to eat oysters, but am afraid of contracting Vibrio vulnificus?  Is there a way to protect myself?

Since thoroughly cooking oysters will destroy the bacteria, oysters can continue to be enjoyed in many cooked preparations by following this advice.

• When you purchase oysters the shells should be closed. Throw away any oysters with shells already opened.


• If cooking oysters in the shell: 
• After the shells open, boil live oysters for another 3-5 minutes or steam live oysters for another 4-9 minutes. (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).

• If cooking shucked oysters:

• Boil or simmer shucked oysters for at least 3 minutes or until the edges curl.
• Fry at 375 degrees for at least 3 minutes.
• Broil 3 inches from heat for 3 minutes.
• Bake at 450 degrees for 10 minutes.

WHAT's BEING DONE TO PROTECT US FROM VIBRIO VULNIFICUS?

The FDA and the ISSC (the Interstate Shellfish Sanitation Conference) have been tasked with reducing and/or eliminating the Vibrio vulnificus virus in oysters. At one time, the FDA proposed requiring all oyster farmers to pasteurize oysters immediately after harvesting. Farmers pushed back because the process is expensive and probably not necessary for oysters harvested in cooler states. Further, farmers in Southern regions currently charge extra for pasteurized oysters and are unwilling to see that profit center disappear. Since then, both groups have put the responsibility for deciding whether to eat oysters on the consumer - making an effort to educate high-risk consumers. No other food products are regulated like this. 

All parties have been sensitive to overreaching regulation. The FDA and ISSC, in partnership with oyster farmers, are looking at ways to save lives, without impacting the vast majority of safe oysters. 

SHELLFISH ALLERGIES 

Then there's the issue of shellfish allergies. If you are one of the 2 percent of American adults who have a shellfish allergy ... bummer.  Here's the good news.  People who are allergic to crustaceans (shrimp, lobster, crab) may not be allergic to mollusks (including oysters).  Since you may go into anaphylaxic shock if you are allergic, you may want to talk to a doctor first before giving it a try.

FINAL THOUGHTS

I hesitated to write this post because I'm here to celebrate the oyster. My hope is that by laying out the scariest scenarios, we can actually put a few fears to rest. Be smart about when and where you eat oysters. Cook them if it makes you feel more safe. Learn more about the oysters you eat and who farms them. Be a smart consumer. And respect the oyster. 

*As their policy states, content on the Food & Drug Administration website is in the public domain.