Tag Archives: food safety

With caution, one can avoid the risk of illness when gathering shellfish

If you are planning to gather some shellfish to eat over Labor Day weekend — or anytime for that matter — state health officials urge you to follow the “three Cs” of shellfish — check, chill and cook.

The state’s Shellfish Safety Map shows areas open and closed to harvesting.
Map: Washington State Dept. of Health

At least 10 cases of an intestinal illness called vibriosis have been reported this year to the Washington State Department of Health, all resulting from people picking oysters themselves and eating them raw or undercooked. The disease is caused by a bacteria, Vibrio parahaemolyticus, an organism that occurs naturally and thrives in warm temperatures.

“The shellfish industry follows special control measures during the summer months to keep people who choose to eat raw oysters from getting sick,” said Rick Porso, director of the Office of Environmental Health and Safety, in a news release. “For those who enjoy collecting and consuming their own shellfish, it’s important that they follow a few simple measures to stay healthy.”

The combination of warm weather, lack of rain and low tides all contribute to the growth of bacteria in oysters growing on the beach.

The state Department of Health uses the “three Cs” as a reminder for recreational shellfish harvesters as well as people who gather shellfish from their own beaches:

  • CHECK: Before heading to the beach, make sure that shellfish in the area are safe to eat. The Shellfish Safety Map, updated daily, will tell you where it is safe to gather shellfish. At the moment, many areas are closed because of paralytic shellfish poison produced by a type of plankton. Unlike Vibrio, PSP cannot be destroyed by cooking.
  • CHILL: Gather shellfish as the tide goes out, so they are not allowed to sit for long in the sun. Put them on ice immediately or get them into a refrigerator.
  • COOK: Cooking at 145 degrees F. for at least 15 seconds should destroy Vibrio bacteria, health officials say. It is not enough to cook them until their shells open.

Symptoms of vibriosis include diarrhea, abdominal cramps, nausea, vomiting, headache, fever and chills. The illness usually runs its course in two to three days. For information see “Vibriosis” on the Department of Health’s website.

Symptoms of paralytic shellfish poisoning usually begin with tingling of the lips and tongue, progressing to numbness in fingers and toes followed by loss of control over arms and legs and difficulty breathing. Nausea and vomiting may occur. PSP can be a life-threatening condition, so victims should seek medical help immediately. For information, see “Paralytic shellfish poison” on the Department of Health’s website.

Besides health advisories, the Shellfish Safety Map mentioned above also includes the water-quality classification, a link to shellfish seasons to determine whether a beach is legally open along with other information,

Geoducks test OK, but what’s behind Chinese ban?

Now it is up to Chinese officials to decide upon shellfish imports to their country, as uncomfortable as that may be for U.S exporters. I’ve begun to learn about international trade policies to better understand the confusing actions of Chinese health authorities.

As you’ve probably heard by now, officials with the Washington State Department of Health have concluded from a new round of testing that arsenic in geoducks from Poverty Bay presents no legitimate health concern. That seems to contradict findings from Chinese health authorities, who cited high levels of arsenic in Poverty Bay geoducks when they suspended shellfish imports from the U.S. West Coast.

Unfortunately, the Chinese have failed to reveal how they came to their findings, and they discarded all the geoducks used in their tests. Divers from the Washington Department of Natural Resources collected new geoducks from Poverty Bay, and state health experts conducted new tests. The findings were released Tuesday, and I covered that in some detail in a story published in yesterday’s Kitsap Sun (subscription). Also, check out Water Ways, Dec. 24, to understand the different types of arsenic.

USTR report

Results from the Washington state health lab showed that arsenic levels in all parts of the geoduck came in under the Chinese limit of 0.5 parts per million, except for the skin. Dave McBride, a toxicologist for the state health department, told me that cooks in both China and the U.S. blanch the geoduck to remove the inedible skin, so that’s not a factor.

But even if one consumes the whole geoduck, tests on the “whole body” found only one composite sample out of 12 that exceeded the Chinese standard. Of course, it would have been more convincing if none of the whole-body samples came in above 0.5 ppm.

A private lab also tested geoducks from Poverty Bay, and those results came in even lower. The differing findings probably resulted from the different methods used, Dave McBride told me. It might be wise to try to reconcile the differences and report the scientific uncertainty (possible range) represented by the two techniques.

Meanwhile, I’ve begun talking to experts on Chinese trade, who say it is not unusual for governments around the world to use alleged health concerns to gain a trade advantage.

As I reported in yesterday’s story, the U.S. Trade Representative, a presidential cabinet post, reported to Congress at the end of last year about what appeared to be unjustified health concerns blocking a variety of agricultural imports into China:

“In 2013, serious problems have remained for U.S. exporters, who are faced with nontransparent application of sanitary and phytosanitary measures, many of which have appeared to lack scientific bases and have impeded market access for many U.S. agricultural products.

“China’s seemingly unnecessary and arbitrary inspection-related import requirements also continued to impose burdens and regulatory uncertainty on U.S. agricultural producers exporting to China in 2013 … Products most affected in 2013 included poultry, pork and beef.”

Dongsheng Zang, a University of Washington law professor who specializes in Chinese trade, and Debra Glassman, faculty director of the UW’s Global Business Center, helped me understand the trade situation for yesterday’s story. Here are some of the key points I came away with:

  • Chinese officials don’t always base their decisions on the best evidence,, even though agreements under the World Trade Organization require them to do so. In 2011, China stopped imports of oysters from Washington state following reports of a few people getting sick from eating raw oysters from Hood Canal. Zang says Chinese officials based their actions only on “media reports.”
  • Import bans often come quickly and take a long time to resolve. That happens not just in China but in other countries and the European Union, especially when the dispute must be resolved by the World Trade Organization.
  • International agreements require that any import restrictions must be the “least-trade-restrictive” to protect the public, such as banning shellfish from specific bays where problems are identified, Glassman said.
  • The Chinese ban on U.S shellfish could be designed for a domestic audience inside China. “I can only speculate,” Zang said. “Food safety is a huge issue in China. It’s really hard to say whether this (geoduck ban) is about public health or domestic policy.”

An official in the office of the U.S. Trade Representative in Washington, D.C., told me (on background) that the office is watching this issue closely. If the shellfish ban develops into a full-fledged trade dispute, that office will become involved.

I realize that geoduck harvesters and government officials don’t want to accuse the Chinese of acting inappropriately. They just hope that the ban will be lifted without a drawn-out dispute. Meanwhile, those in the industry are losing millions of dollars by being shut off from their most important market for the giant clams.

Chinese geoduck ban creates industry turmoil

It was shocking to hear that China had banned imports of clams and oysters from most of the U.S. West Coast, This announcement came after Chinese health inspectors reported high levels of paralytic shellfish poison and arsenic in two shipments of geoducks coming into that country. (KUOW had the initial report.)

Photo: Washington Sea Grant
Photo: Washington Sea Grant

It turns out that one shipment of geoducks came from Poverty Bay near Federal Way in Puget Sound, and the other one came from Ketchikan, Alaska.

Washington state government as well as the state’s extensive shellfish industry pride themselves on a monitoring program designed to ensure that PSP levels for harvested geoducks remain well within safe limits. I frequently report PSP (“red tide”) closures when they occur on recreational beaches — and commercial shellfish are checked even more frequently.

The monitoring program for Washington state shellfish is recognized worldwide for its ability to keep unsafe shellfish off the market.

The initial memo (PDF 33 KB) from the Chinese government said inspectors had found levels of PSP at 30.2 mouse units per gram. Mouse units? I had never heard of such a measurement, although I know that live mice are often used in the monitoring tests. I learned that “mouse units” was an older standard of measurement, replaced by micrograms of toxin per 100 grams of shellfish tissue.

The use of mouse units was the first issue that threw everybody off. I received an explanation from Jerry Borchert of the state’s Office of Shellfish and Water Protection, and I offered this explanation in a story I wrote for today’s Kitsap Sun (subscription):

“The Dec. 3 letter imposing the shellfish embargo stated that paralytic shellfish poison was found in concentrations of 30.2 mouse-units per gram. Mouse-units are an older standard, based on the amount of poison it takes to kill a mouse. The more common measurement today is micrograms of toxin per 100 kilograms of shellfish tissue, Borchert said.

“‘We need to know what conversion factors they used,’ he said. ‘Based on the best information we have, which is sketchy, the levels were between 600 and 1,500 micrograms per 100 grams.’

“In contrast, reports on geoducks from the Poverty Bay tract were no greater than 62 micrograms between Sept. 26 and Oct. 24, according to a health investigation completed Friday. The most likely harvest date was found to be Oct. 5.

“Authorities will close an area when the toxin level reaches 80. In fact, the high toxin levels suggested by the Chinese memo might not have been reached in geoducks found anywhere in Puget Sound this year, Borchert said.”

You can read the report, “Investigation and Results Related to the Geoduck Shipment Linked to the Shellfish Import Ban Imposed by China” (PDF 209 KB).

Confusion over the toxin levels found by the Chinese inspectors has created a great deal of anxiety throughout state government and the shellfish industry in Washington state. Nobody wants to say that the Chinese made a mistake, especially when the only data available is a terse finding in a memo (PDF 33 KB) transmitted to U.S. authorities. In fact, everyone I have talked to has been careful not to say anything negative at all until the facts are all in.

The chance that the shellfish exported to China exceeded the international standard of 80 micrograms per 100 grams seems possible, given that samples sent to state officials reached 62. That could invoke a response, even though the action level of 80 is considered within a significant margin of safety. But if the Chinese inspectors are reporting toxin levels higher than 600, that raises other issues.

What about poaching? I think it would be hard to rule out the possibility that somebody illegally sold geoducks from another area where PSP levels were higher and said they were from Poverty Bay. Whether that could happen depends, at least in part, on how well officials are able to track the geoducks through the market.

John Weymer of the Puyallup Tribe told me that officials were able to track the geoducks in question back to a specific boat working in Poverty Bay. Since it was a harvest by the Puyallup Tribe, tribal inspectors were on hand to make sure that the harvested geoducks were accounted for until sold to an independent buyer, he said. There is no doubt, he added, that the geoducks sold from the bay in October met health standards.

Although numerous areas of Puget Sound showed toxin levels above 80 micrograms in some types of shellfish, I’m told that the number of areas that reached 600 to 1,500 in geoducks were rare, if that happened at all. Such a finding would create more doubt about the accuracy of the Chinese testing.

One of the things I wondered about was whether the Chinese could be acting in retaliation for ongoing U.S. actions regarding the safety of foods imported from China. Bans on Chinese chicken were imposed and then lifted, amid Chinese complaints to the World Trade Organization. Questions of food safety have become entangled in issues of fair trade between the two countries.

I’ve raised this question of a trade battle with several people. Most tell me that if this were a trade issue, the Chinese would have used the opportunity to make a political statement. Instead, the Chinese memo was limited in scope, although the financial impact to the Washington shellfish industry could be significant.

Some people are quietly speculating that the Chinese have taken this action to manipulate prices. If geoduck harvesting is shut down in Washington state, the price of wild geoducks from the U.S. will drop and markets will improve for Canadian and Mexican geoducks. I’m told that the Chinese can make more money operating in those countries, although I have been unable to verify that so far.