Dangerous delicacy
A raw oyster can kill you. What you should know about eating shellfish in the summer
Summer is a deadly time for eating shellfish in Florida, particularly raw oysters.
Oysters served in Florida and traced back to Louisiana are infecting people with vibrio vulnificus, a bacterium that normally lives in warm seawater. The summer months of May through October are when the bacterium flourishes, so eating raw shellfish this time of year is the riskiest.
Already in 2022, six people in the state are dead from vibrio vulnificus, including a man from South Florida in July. At least 28 Floridians have become sick.
Along with oysters, vibrio vulnificus also can get into mussels, clams and scallops known as “filter feeders” because they filter the water for their food. Although vibrio is found in many locations, in Florida the infections primarily are from oysters from the Gulf of Mexico, although vibrio in the past has been found in oysters from the Eastern Coast as well.
Many have heard the refrain: Never eat oysters in the months without an “R” in them. That would be May, June, July, and August. However, you can get sick from eating raw or undercooked oysters during any month.
Determine the risk
There are ways to enjoy shellfish and stay safe.
Eating the shellfish steamed will help, but only if it’s cooked properly at the right temperature, for the right amount of time. Oysters need to reach an internal temperature of at least 145 degrees for 15 seconds to kill vibrio. Eating oysters, clams, mussels and scallops fried, charbroiled or sauteed is the safer way to go.
“When you eat anything raw, it comes with a risk,” said Dr. Razieh Farzad, seafood safety extension specialist for Florida Sea Grant at the University of Florida. “When I go to a restaurant and eat shellfish, I ask where it is sourced and how they cook it.”
You can’t detect vibrio by smell, and putting lemon or hot sauce on the oyster won’t kill the bacterium, Farzad said.
Fish also can ingest bacterium-infected oysters and that could cause harm, too.
“We don’t see it that often because people cook fish and because we usually eat filets, not the digestive track,” she said.
Florida law requires that all restaurants, seafood markets and retailers post warnings about the dangers of consuming raw oysters.
Many people ingest vibrio, and it makes them sick with symptoms such as vomiting, watery diarrhea, stomach cramping, nausea, and fever. Dr. Joshua Lenchus, chief medical officer of Broward Health, says that scenario is most common.
“The symptoms start in 24 hours and usually after three days they are gone,” he said.
Only about a fraction of those who ingest the bacterium get severely ill or die.
The Centers for Disease Control and Prevention estimates that about 80,000 people get vibriosis —and 100 people die from it — in the United States every year.
And, while drinking beer and eating oysters are a favored pastime, alcohol consumption — and its potential damage to the liver — makes drinkers more vulnerable to a dangerous bacterium in the shellfish.
Those who die from vibriosis tend to have other factors that make them more vulnerable, such as weakened immune systems, liver disease, diabetes or HIV. In those rare and potentially deadly instances, vibrio invades the bloodstream, causing fever, chills, and septic shock.
“A recent study showed that people with these pre-existing medical conditions were 80 times more likely to develop vibrio vulnificus bloodstream infections than healthy people,” the Florida Department of Health website said.
That bloodstream infection is what happened with Roger “Rocky” Pinckney who died after eating a raw oyster at a celebratory dinner at Rustic Inn Crabhouse in Fort Lauderdale last month. Pickney arrived at the hospital with a fever and abdominal pain two days after eating oysters. After a week of emergency surgeries and a double amputation, he was pronounced dead.
Cautious steps
If you start feeling ill after eating shellfish, Lenchus says, drink lots of fluid. “Most people end up in the hospital because they can’t keep up with fluid,” he said. However, if the fever persists, he said you may need to get antibiotics, adding: “After two days if you are not better at all, it’s a good idea to seek medical attention.” Vibrio vulnificus is responsive to antibiotics, but the medication must be taken quickly.
If you are buying oysters or clams to cook at home, make sure all the shells are closed, says Farzad. “I suggest asking for the tag to see the time of harvest and if you see shells open, throw them away.”
It is not just eating oysters that can put you at risk. Swimming with them and shucking them can put you at risk, too. People with open wounds also can be exposed to vibrio vulnificus if seawater gets into the cut and the bacteria gets into the bloodstream. While some have referred to vibrio vulnificus as a flesh-eating bacteria, Lenchus at Broward Health says that’s not the case. You have to have a cut for it to get into your bloodstream, and once it gets in it could progress and cause sepsis, he said.
Other seafood that is risky to eat raw includes crab meat and sushi.
The U.S. has had outbreaks of vibrio parahaemolyticus infections linked to eating fresh crab meat. The symptoms are similar to those from eating raw oysters. The CDC recommends looking for the word “pasteurized” on the label when eating crab meat. Pasteurization uses a high temperature for a long enough time to kill illness-causing germs.
Vibrio parahaemolyticus, the bacteria in crabs, is estimated to sicken about 45,000 people in the United States each year.
With sushi restaurants now populating South Florida, eating raw fish carries risks, too. While sushi-related infections are uncommon, eating sushi is not entirely without risk. Raw fish or seafood can contain disease-causing bacteria, parasitic worms, toxins, and viruses
“Sushi is highly regulated in the US in ways to protect us from parasites or bacterial infection,” Farzad at UF explained. “Restaurants have food codes so I assume if I am eating in a restaurant it is safe, but anytime you are eating something raw you are dealing with risk.”
Sun Sentinel health reporter Cindy Goodman can be reached at cgoodman@ sunsentinel.com.