To avert illnesses, a new plan uses varying temperatures to assist Washington state growers of oysters destined to be eaten raw.
When a work trip sent Jill Poretta to Seattle two summers ago, the New Jersey resident decided to make a vacation of it, a chance to see the sights and enjoy the city’s fine dining.
But an appetizer plate of mixed oysters soon spoiled the trip. The day after her dinner at a restaurant on the central waterfront, Poretta became so violently ill she had to take a cab to a hospital at 3 a.m.
“I couldn’t get out of the car,” recalled the 43-year-old legal researcher from Haddonfield, N.J. “I’m vomiting as soon as I walk in the door.”
Poretta had to cut short her trip and head home, where she says she felt exhausted and ill for two weeks. Tests showed she’d contracted Vibrio parahaemolyticus, known as Vp, a leading cause of seafood poisoning in the U.S.
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In July 2013, her case was one of four traced to Hammersley Inlet, an arm of water in southwest Puget Sound. State health officials closed the shellfish-growing area — but only after Poretta and others had gotten sick.
Starting this month, there’s a new approach — a first-in-the-nation effort by state health officials and shellfish growers — to curb heat-loving Vp long before it hits the plate. It requires quicker cooling of oysters when air and water temperatures get too warm and closing at-risk commercial beds before illnesses occur.
The protocol requires real-time monitoring to determine how fast harvested oysters must be cooled to a safe 50 degrees — and when they shouldn’t be gathered at all.
The rules aims to reduce the 40 to 45 infections tied to Washington oysters that are confirmed each year and another 6,000 to 7,000 cases that go undiagnosed, health officials said.
“Anytime you’re basically waiting for illnesses to trigger an action, it means you’ve missed your peak window for public-health protection,” said Laura Wigand Johnson, a marine and environmental scientist who led the state’s two-year process to put the Vp procedures in place.
But the new strategy, which took effect May 1 and runs through Sept. 30, has sent ripples of concern through Washington state’s commercial shellfish industry. That includes 329 licensed private growers and 39 tribal producers, though only about 150 deal in oysters, Johnson said.
All say they are in favor of reducing hard-to-predict Vp illnesses, even as they acknowledge the move requires new duties, new documentation and extra staff.
“It’s quite a shift in the way we do business as it relates to oysters for raw consumption,” said Bill Dewey, a spokesman for Shelton-based Taylor Shellfish Farms, the largest producer of farmed shellfish in the U.S. “We’re working through the nuts and bolts of how we do it.”
Those nuts and bolts apply to shellfish harvesters and dealers who supply fresh oysters to market to be eaten raw, not oysters designated for shucking or post-harvest processing.
The updated protocol applies only to Vp control. State health officials separately monitor commercial and recreational shellfish areas for other threats, including marine toxins that cause paralytic shellfish poisoning and lead to so-called “red tide” closures, and closures because of contamination with pollution or fecal matter from sewage.
Plan of action
The Vp plan divides growers into three risk categories, lowest to highest, based on the number of illnesses reported in a given area in the last five years. Category 1 includes growing areas with one or fewer reported Vp cases in that time frame. Category 2 includes growers with more than one but fewer than five cases and Category 3 includes areas with five or more Vibrio cases during the five-year period.
Of the 102 oyster-growing areas included on the list, 11 are ranked in Category 2 and five are included in Category 3, according to state Department of Health records.
Hammersley Inlet, where the oysters that sickened Jill Poretta were harvested, ranks in the second risk category, state data show.
Now there are mandates on how quickly growers must cool their oysters to a safe 50 degrees Fahrenheit based on air and water temperatures logged in each risk area, and when to close beds based on risky readings.
For instance, growers in low-risk Category 1 have up to nine hours to get their oysters cooled to 50 degrees — except when the air temperature rises above 90 degrees. In that case, they have seven hours to final cooling, or as few as five hours if the local water temperature is between 68 and 70 degrees.
Growers in high-risk Category 3, however, will have to hustle oysters to cooling within five hours, maximum, or within three hours when air temperatures top 80 degrees. They have just one hour from harvest to cooling when the water warms above 64 degrees, the plan states.
Between July 1 and Aug. 31 — the highest-risk months — there will be 24-hour closures for shellfish beds when water temperature climbs above a minimum of 66 degrees or a maximum of 70 degrees.
That’s because warm air and water create prime conditions for Vp to flourish, said Johnson, manager of the state’s shellfish licensing and certification section. Vp is a naturally occurring marine pathogen that thrives in brackish saltwater areas.
“It’s one of the fastest-growing bacteria in the world,” Johnson said. “It can double in eight minutes in ideal conditions.”
Vp levels can vary significantly from day to day, even hour to hour, said Angelo DePaola, lead seafood microbiologist for the Food and Drug Administration (FDA). Some strains are also more infective than others and may cause illnesses at lower exposure.
“The Washington plan … attempts for the first time to use near real-time air, water and oyster temperature observations in growing areas,” he wrote in an email. “This is a sensible approach as it accounts for temperature anomalies.”
Previous efforts to control Vp after a 2006 outbreak that sickened 113 people in Washington, plus more in other states, fell short, Johnson said. The infections cause days of nausea, vomiting, fever and diarrhea and can be dangerous for people with compromised immune systems.
“The push for this latest revision is because we just didn’t see the reduction in illnesses that we were expecting,” she said.
Overall, Vibrio food poisoning has been rising in the U.S. in recent years, jumping 52 percent from 2006-2008 to 2014, according to the Centers for Disease Control and Prevention. All strains of Vibrio cause about 80,000 illnesses and 300 deaths in the U.S. each year; Vp cases account for about two-thirds of those reported, the CDC said.
Still, not everyone affected by the state’s effort is sure about the change. Tracking the data will be time-consuming and expensive, shellfish growers said. It’s not yet clear whether the total days of closure will be more or fewer — or whether they actually will reduce Vp infections.
“The new rules are an experiment to see if this will reduce the number of illnesses,” said Kelly Toy, shellfish manager of the Jamestown S’Klallam Tribe.
Both the Jamestown and the Nisqually tribes say they’ll be forced to close their shellfish beds completely in July and August because there’s no way the high-risk areas will pass the temperature tests.
“We’re just rearranging when we do our harvest,” Toy said. “But it’s still an economic impact. People would normally be getting paid in July and August.”
Margaret Barrette, executive director of the Pacific Coast Shellfish Growers Association, says her group represents a third of the growers in the state. Though everyone supports the goal of reduced illness, she said, smaller growers will feel the pinch of extra staffing needed to monitor air and water temperatures and cooling times.
“The rule that went forward is not perfect and still needs some work,” said Barrette, whose group pushed the state to review the plan in 2017. “Some of our smaller farms are feeling like this is a pretty heavy lift.”
One key sticking point has been the requirement that growers publicly report their shellfish-harvest volumes during the control months. Until now, there’s been no way to know how numbers of illnesses compare to the amount of raw oysters actually harvested — and served.
But that forces growers to relinquish proprietary information that could affect state and federal taxes or what they pay according to tribal harvest-sharing agreements, said Scott Grout, operations manager for Gold Coast Oyster in Shelton.
“The growers have no incentive to give honest, accurate information,” he said.
Still, after two years of sometimes-contentious meetings, health officials and shellfish growers alike said they’re relieved to have reached a deal. It will be put to the test in the next few months, which are expected to be hot and dry, conditions that could allow Vibrio pathogens to flourish.
Johnson said she’s a little nervous about rolling out the updated procedures now, but understands it has to start sometime.
“I just get worried about putting too much stock in the results of one year to say if it’s a success or a failure,” she said.
For diners and visitors like Poretta, who remembers only too well her debilitating infection, the changes can’t come too soon.
“They should never have been able to distribute it,” she said. “When you see oysters on the menu, you don’t think you’re going to get Vibrio.”