A new test for shellfish

Simpler test seen as boon to farmers; home tests may be possible

Posted: Sunday, August 12, 2001

A new shellfish screening test may be the difference between life and death for clam eaters, geoduck harvesters and laboratory mice.

Modeled after home pregnancy tests, the Maritime In Vitro Shellfish Test, or MIST, makes it possible to check shellfish for the deadly Paralytic Shellfish Poisoning toxin at home or at sea.

Paralytic Shellfish Poisoning (PSP) is common in Southeast Alaska, particularly along Lynn Canal and near Ketchikan and Metlakatla. Since 1993, 56 people have been sick from eating contaminated shellfish in Alaska, 14 of them in Southeast. Occasionally people die from the toxin.

"There needs to be some way for people to determine the safety of shellfish, because of the large amount that's consumed by people and the bad history we've had," said Rodger Painter, vice-president of the Alaskan Shellfish Growers Association. "In PSP research, Alaska's the Mecca."

The prevalence of PSP has restrained what might otherwise be a booming shellfish industry, Painter said. Currently about a dozen farms grow oysters, clams and other shellfish in Southeast Alaska. To keep their products safe, shellfish farmers and harvesters have to send samples to the state Department of Environmental Conservation lab in Palmer.

At the lab, scientists inject a sample of the shellfish into a mouse and record how long it takes to die. The Palmer lab does about 1,200 PSP tests a year, which means 1,200 mice.

The lab test is also expensive and time-consuming. Each mouse test costs $125 a shot. MIST tests cost $20 each, but Jellett Biotek Ltd. is selling them to Alaskans at half price for a year under a deal with the Alaska Science and Technology Foundation. The foundation gave the Nova Scotia biotechnology company a $300,000 grant to help develop the test.

"The MIST test has been real exciting for us," said Sharon Gray, co-owner of Canoe Lagoon shellfish farm near Prince of Wales Island, one of the farms involved in trials of an early version of the tests. "I was really impressed with the PSP test kits they had last year."

The MIST kit is still new and has some glitches to work out. Jellett Biotek had to recall 2,000 kits in July after the dye failed, causing three false negative readings. The inconsistent dye was replaced and new MIST tests were shipped last week, said Bob Chaney, Alaska Science and Technology Foundation administrator.

"The recall has not shaken our confidence in them," Chaney said.

Nor Gray's, although one of the faulty tests occurred on her farm.

"I am still very much gung-ho on Jellet Biotek and their product," Gray said. "I am very much looking forward to them working out all the kinks in their products."

The biggest advantage for Gray will be tracking PSP levels in her shellfish more closely. Twice a month the Palmer lab tests samples from her farm for free, but the rest of the month she's allowed to sell the shellfish without testing.

"Basically the testing program that the state of Alaska has sucks," Gray said. "It's safe enough to keep people from getting sick or seriously ill, for the most part, but it doesn't protect me."

When the PSP plankton is in her area, Gray plans to use the MIST test to fill in for the weeks she doesn't send samples to Palmer.

Painter has similar plans for using the MIST kit at his shellfish farm on Sea Otter Sound. In September and October, when he historically has outbreaks of PSP, he'll use the MIST test. If it shows PSP, he'll know to adapt the harvest and testing of his oysters and littleneck clams.

"This will give us an extra tool, because now using the kits we'll know to make that shift immediately," Painter said.

Southeast shellfish farmers and divers alike complain it is difficult shipping tests all the way to Palmer.

"I might as well be sending a PSP test to Japan," Gray said. She express mails the sample, then often spends several hours on the phone trying to track the package when it gets lost on the way. Generally when she sends a sample it takes two days to get results. Meanwhile the rest of the harvest waits in her refrigerator. By the time the oysters and clams reach her buyers down south they are already five days old, and they are only at peak quality for seven days, Gray said.

The stakes are even higher for geoduck harvesters, since current testing policies make it impossible to sell geoducks live. In the geoduck market, live geoducks bring a price two to five times higher than processed clams. Last year Alaska geoduck harvesters earned $1.10 per pound for processed geoducks, but could have gotten up to $4.50 per pound if the geoducks were sold live. The average geoduck weighs two pounds, and bigger ones weigh up to 20 pounds, so the price difference means big bucks.

"It's a very significant difference," said Julie Decker, executive director of the Southeast Alaska Regional Dive Fisheries Association.

Alaska divers can't sell the geoducks live because they must wait two days after harvesting for results of PSP tests done at the Palmer lab. About half the time the lab finds PSP in the geoduck samples.

The MIST test kit will allow divers to check several geoducks before deciding to harvest in a specific area.

"We could go to the grounds ourselves, dig the geoducks and test them ourselves to see if these are hot or not," Decker said. "If they're not we could dig the geoducks and send them to the lab, but if they're hot we wouldn't even bother."

Eventually SARDFA would like to be able to ship out live geoducks from harvest sites that have been certified as safe from PSP. SARDFA has a grant to start monthly testing of 15 geoduck harvest sites this fall. They'll double test the sites, using the MIST test and also sending samples to the Palmer lab. That will help determine whether the MIST test alone is reliable enough to screen harvest sites and someday allow for live geoduck sales.

"We're excited, but we're containing our excitement until we find out just how it's going to work for us," Decker said.

The Alaska Science and Technology Foundation also hopes villages and Native groups will make use of the MIST test to monitor beaches used for subsistence clam or mussel harvests. Of the 33,000 miles of shore in Alaska, the DEC monitors only Kachemak Bay.

Southeast Alaska Regional Health Consortium will use the MIST test to study the PSP frequency at six popular clamming beaches near Sitka, said Paul Audette, a field environmental health technician for SEARHC. On any extreme low tide in the early spring or fall, Sitka residents go out with buckets and shovels to collect clams for dinner, Audette said.

"My whole family used to do it religiously every spring and fall and there were 10 of us out there," Audette said.

The MIST test is simple enough that Audette's family could have tested their clams in the kitchen before cooking them.

"If you can bake a cake you can do this," said Robert Chaney, technology administrator for the Alaska Science and Technology Foundation. "That's all you need is a simple kitchen procedure."

A representative sampling of the clams, mussels or geoducks collected are blended together in a solution. A few drops of that mixture is placed on a test strip the size of a tongue depressor. After 20 minutes, the color change indicates whether the sample was safe or not.

"It's kind of almost like a high school science lab project," Decker said.

Eventually the test may be simplified even further.

"The goal is to be able to do this on the back of a four-wheeler or on the trunk of a car," Chaney said.

The test worked fine at the food safety lab in Palmer, where more than 2,000 were used in trials, said Richard Barrett, chief of laboratory services for the DEC. He sees it as a useful tool for subsistence users monitoring their beaches.

"It will work relatively well for a field kit," said Barrett said. "It's not an approved test by any shape or form."

The American Association of Analytical Chemists has recognized MIST as a viable test. But it needs approval from the Interstate Shellfish Sanitation Conference or American Public Health Association before the state will endorse it.

"It's user beware," Barrett said. "It's got its good points, but I don't know how it's going to be used out there."


Kristan Hutchison can be reached at khutchison@juneauempire.com.

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