Sex, Death and Oysters

Beneath the muddy waters of Galveston Bay lies one of the greatest seafood treasure troves on earth

Efforts of the FDA's Interstate Shellfish Sanitation Conference, a group of federal and state regulators and shellfish industry representatives, to reduce the number of V. vulnificus cases haven't made much progress. Some members want to mandate postharvest treatment of Gulf Coast oysters by freezing, flash sterilization or washing to reduce the disease during the high-risk time of year. Others favor increasing the supply of treated oysters to provide more consumers with a less risky option. Unfortunately, the treated oysters don't taste all that great raw.

The Gulf Coast oyster industry argues that the education of the "at-risk consumer" is the best way to combat V. vulnificus infections. The vast majority of consumers have nothing to worry about and shouldn't be deprived of their right to eat regular raw oysters, they argue.

But educating consumers has proved difficult, as so little is known. The first reported case of V. vulnificus illness was in 1979. And some misunderstandings about the bacterium have been spread by the media. In "The Perpetual Oyster," a five-part series of articles about oysters in Forbes, Charles Dubow writes, "Although it is fairly easy to spot a 'bad' oyster -- not only do they look dry and shriveled but usually smell something like rotten eggs -- too many people over time have wished they had paid just a little more attention to what they were eating. Bad oysters are full of bacteria (Vibrio Vulnificus for those who care)…"

Some 430 oyster boats are working in Galveston Bay this season, more than double last year.
Troy Fields
Some 430 oyster boats are working in Galveston Bay this season, more than double last year.
The keepers are piled on deck, and the empty shells and small oysters are shoved overboard.
Troy Fields
The keepers are piled on deck, and the empty shells and small oysters are shoved overboard.

Before the invention of refrigeration, Dubow goes on to say, it was best not to eat oysters in months without an "r." He concludes, "Well, these days that is no longer a problem and one can eat oysters with impunity 12 months a year -- but just be sure to smell them first."

I wonder if Charles Dubow is still alive. If so, it's not because of his knowledge of oysters. The stinky, shriveled oyster he describes is more likely one that has died in transit. In fact, V. vulnificus is an odorless, tasteless and completely undetectable marine organism that thrives in shallow coastal waters in warm weather, and it's present in both good oysters and ones that have gone "bad." Nor does V. vulnificus have anything to do with pollution or red tide, as many people seem to believe.

It may be safe to eat raw oysters all year long if you don't have a compromised immune system. The problem is, few people know exactly what shape their immune systems are in. And other factors can have an effect. For example, while stomach acids usually kill much of V. vulnificus, some common medications, such as antacids, allow the bacteria to multiply. Antacid users are now considered "at risk" and are urged to avoid raw oysters.

So where does an enlightened food lover draw the risk-and-reward line when it comes to raw Gulf Coast oysters?

On the two extremes, there are the oyster guys who want to sell you oysters all year round regardless of the increased bacterium levels and the fact that summer oysters don't taste very good. And then there's the Center for Science in the Public Interest, which insists that all Gulf Coast oysters should be sterilized. The truth probably lies somewhere in the middle. And this is the time of year to make up your mind. "We see a cluster of cases every year in late March and early April, when the water heats up again," says Gary Heideman, who mans the Seafood Safety Desk at the Texas Department of Health.

Heideman has some good advice on the subject of raw oysters. "Even though Vibrio vulnificus has no effect on most healthy people, there is always some risk," he says. "But you can improve your odds." Heideman suggests that if you want to eat raw oysters with a minimum of risk, then keep an eye on the water temperature. Little or no V. vulnificus is detectable when the water temperature at the point of collection is below 65 degrees. Generally, that happens between the beginning of December and the middle of March. (You can check the exact temperature in the marine forecast at

Based on Heideman's advice, I've decided to treat oysters as a seasonal food. I'll eat raw oysters in the winter, when the glycogen makes them sweet and the bacteria are scarce. When the water warms up in the spring and the bacteria start to swarm, I'll switch to cooked oysters. In the summer, after the oyster has spawned, it has little flavor or substance left. And that's also when the bacteria are the highest. So I might as well observe the "never eat oysters in months without an 'r'" rule.

But it's good to remember that even among the at-risk population, very few people die from eating oysters. Just to put the odds in perspective, Florida health officials and the USDA state: "In 1992, an estimated 71,000 Floridians with liver damage consumed raw oysters and nine died from Vulnificus infections. Four of the victims suffered from cirrhosis and a fifth had a history of heavy drinking."

The odds of dying from eating an oyster are around a million to one.

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