The government and seafood industry must work together to reduce illnesses from Vibrio vulnificus – a naturally occurring but potentially fatal bacterium found in Gulf Coast oysters – says the Government Accountability Office.

The GAO this week called on the Food and Drug Administration (FDA) and the Interstate Shellfish Sanitation Conference (ISSC) to agree on a reasonable goal for reducing the rate of Vibrio illnesses in the U.S. and to establish a way to measure progress toward that goal. 

Vibrio vulnificus is mainly found in oysters from the Gulf of Mexico, where warm waters provide the ideal growing conditions for it during the summer months. The presence of Vibrio vulnificus in oysters has long been a public health concern, as well as a source of friction between the oyster industry and the federal government. The bacterium causes an average of 32 illnesses each year, and about half of those cases are fatal.

Infections from this strain of Vibrio do not usually pose a threat to the general population, but can be life-threatening for those with compromised immune systems, including people with liver disease or diabetes.

For the past two decades, finding a way to reduce Vibrio illnesses has been a topic of debate among the ISSC – a coalition of industry members and state and federal regulatory agencies that develops guidelines for shellfish safety.

The conference first addressed the problem by launching a campaign to educate high-risk individuals about the dangers of eating raw or undercooked oysters by reaching out to doctors and restaurants – which now display a warning about undercooked shellfish on menus.

When this initiative failed to achieve a long-term reduction in the rate of Vibrio vulnificus illnesses, FDA announced in October of 2009 that it would soon require all oyster producers to use a form of Post Harvest Processing (PHP), the term for any approved method for sterilizing oysters before raw consumption – including irradiation, salt treatment and low-heat pasteurization among other processes. The agency also announced a new goal: to eliminate V. vulnificus illnesses as fully as possible, thus replacing its old objective of reducing them by 60 percent.

The decision to require mandatory pasteurization was met with strong criticism from oyster producers, who insisted that these expensive processes would drive many seafood companies out of business. In addition, they argued, a 60 percent reduction in Vibrio illnesses was a more achievable goal than 100 percent. 

These industry members succeeded in stalling FDA’s measure by pointing out that it needed the approval of Congress to take effect.

Last week at ISSC’s biennial meeting in Seattle, the organization voted to move away from the goal of a reduction in rates of illnesses and instead to aim for lowering the overall risk of contracting Vibrio from Gulf oysters. Vibrio danger will now be measured using a “risk calculator,” originally developed by FDA, which the agency has since deemed inaccurate.

The decision to reduce perceived risk rather than actual illnesses was roundly criticized by consumer advocates.

“They’ve gone to assessing what a piece of paper, what the computer tells them, and ignoring the reality of people getting sick and dying from a preventable disease,” said David Plunkett, senior staff attorney for the Center for Science in the Public Interest.

However, industry members say that this is the right move, as the risk calculator takes into account how many oysters are distributed in a given year and adjusts for fluctuations in these numbers rather than simply counting how many people get sick.

The new resolution will require FDA approval before it can take effect. However, FDA representatives made it clear at the conference that they are not likely to support a measure that does not include a specific metric for measuring progress toward risk reduction.

“How does FDA effectively evaluate it when we don’t have something we can say we’ve specifically achieved?” asked Paul Distefano, seafood safety expert for the agency.

Distefano made it clear that even if ISSC agreed to aim for an illness risk reduction rather than actual illnesses, FDA would still be looking at the number of illnesses to assess the industry’s Vibrio controls.

“When we look at how well this is working, we’re going to be looking at illnesses at the national level,” he said at the conference.

How to Accomplish a Reduction in Vibrio

As for measures to achieve a reduction in Vibrio – whether in actual illnesses or risk – the GAO says that requiring Post Harvest Processing for all oyster producers is currently unrealistic.

Indeed, an FDA-commissioned study by the Research Triangle Institute found that implementing such measures would take at least 3 years, and would cause 14 percent of Gulf seafood operations to shut down during warm summer months.

Mike Voisin, CEO of Motivatit Seafoods in Louisiana, says mandating PHP for all companies during vibrio danger months would take away the advantage of being able to charge more for pasteurized oysters, a profit margin that keeps those processers who use PHP afloat. All processors would suffer if this profit margin for the PHP market is removed and companies can’t charge more to make up for its cost, he explains.

“It’s allowing the market to pull [pasteurization] in rather than a regulation enforcing it,” he says.

Under current ISSC guidelines, companies have 5 alternative safety measures to pasteurization during  the Vibrio danger season:

– Stop harvesting during the time period when Vibrio is known to be prevalent in water

– Close oyster beds in areas where the temperature rises above 70 degrees

– Shuck harvested oysters

– Divert oysters harvested in warm waters out of raw market

– Only harvest during certain hours and refrigerate product immediately after harvesting when water temperature rises above a certain temperature (that number is currently under review by ISSC, but is likely to be 70 degrees – 2 degrees higher than that recommended by FDA)

It’s this last protocol that oyster producers have historically used, and will likely use in the future, because it allows them to continue operating in summer months at the lowest additional cost.

However, Plunkett says, this method leaves too much room for error.

“This control can’t be checked,” he says. “The state doesn’t send people out on these boats to check for temperature. FDA can’t get down there and do it. How are you going to make this accountable?” he asks.

Further, this process does nothing to reduce the amount of bacteria on the product, but merely prevents more from growing, he points out.

According to Plunkett, oysters harvested from the Gulf during Vibrio danger months should not be allowed to be distributed for raw consumption unless they are pasteurized.

“If you can’t afford to make a product that’s safe,” he says, “do we really want you in the market? We certainly wouldn’t let somebody build a car if they couldn’t afford to install seatbelts.”

Indeed time and temperature controls are proving difficult for the Gulf industry, says Bill Dewey, director of Public Policy and Communications at Taylor Shellfish in Washington state. Dewey serves on ISSC’s Vibrio vulnificus management committee.

“It’s not going real well,” he told Food Safety News. “Some states are really struggling with it, both from an enforcement standpoint as well as an industry implementation standpoint,” said Dewey, whose own state deals with other species of Vibrio bacteria — Vibrio parahaemolyticus — which are generally less deadly than Vibrio vulnificus but can also cause gastroenteritis.

Challenges include keeping trucks chilled in hot summer months and finding adequate space to store and chill oysters, among others, he explained.

The committee is now considering ways to make these controls more practical for harvesters.
In the meantime, Voison says the key to Vibrio control is educating the at-risk consumer, rather than targeting the industry.

In his view, Vibrio management is a private health concern, to be managed by at-risk individuals and their doctors rather than monitored by public health officials.

“There’s no other product that I know of that’s regulated to be processed for at-risk consumers,” says Voisin. “They educate somebody who’s allergic to peanuts about their allergies. They don’t ban peanut butter or remove the aflatoxins from it.”

Voisin says ISSC has already distributed letters to doctors in Gulf states alerting them to the risks of Vibrio, and that FDA should do the same.

Nevertheless, he says, the oyster industry is doing its best to implement time and temperature controls and meet other ISSC requirements related to the bacteria.

And in the long term, FDA is not giving up on elimination of Vibrio, and what food safety officials see as preventable illnesses.

“This challenge that we’ve been facing for almost 20 years now has not been easy,” Distefano said at the Seattle meeting. “It’s been extremely difficult for all of the states. It’s been very difficult for FDA. It’s painful to agencies. But we have a problem we need to resolve. We have illnesses that cause deaths in half the victims. That’s serious. And there are controls out there that could completely eliminate that. We would like to see this industry move in that direction.”