The red tide poisoning this week of a family of four from Harrington was an accident that occurred well outside the state’s monitoring system, officials with Maine Department of Marine Resources said Friday.

DMR scientists conduct red tide tests weekly at numerous sites along the Maine coast, the officials said. The mussels that poisoned fisherman Randy Beal and his family came from a barrel Beal found floating in the ocean off Jonesport.

“I call it a needle in a haystack,” DMR Commissioner George Lapointe said of the floating barrel. “That’s what it is.”

Randy Beal was listed in serious condition late Friday evening at Eastern Maine Medical Center, while his wife, Brenda Beal, was in fair condition. A third family member, Jonathan Fickett, was discharged Friday.

A fourth family member was treated at Down East Community Hospital in Machias and was released Tuesday.

Lapointe said the state monitoring program is targeted at areas where licensed harvesters are known to cultivate or gather bivalve mollusks such as clams, mussels, oysters and scallops. Other types of shellfish such as crabs and lobsters are not susceptible to red tide contamination.

No one should eat shellfish harvested from outside areas where licensed fishermen operate, the commissioner said.

“That barrel could have come from anywhere,” Lapointe said. “It’s not just a seafood message: Know where your food comes from.”

State officials said they have tested areas around Jonesport, near where the barrel was found, and have found no evidence of red tide contamination.

According to Darcie Couture, director of DMR’s biotoxin monitoring program, red tide comes from poisonous phytoplankton blooms that happen offshore. Water conditions near shore are not conducive to such blooms, she said, but they can wash in toward shore from deeper water.

DMR’s first line of red tide testing usually is at the end of peninsulas and on outer islands, Couture said, because those tend to be the first places where red tide is detected as it washes in from the open ocean. The department also has about 70 buoy stations offshore where it ties up bags of shellfish that it later tests.

“For red tide, that’s probably the most dangerous place to be, is offshore,” she said.

The department checks its routine testing sites along the shore at least once a week from March through late October or November, the period when phytoplankton blooms are known to occur, according to Couture. Some sites are tested more frequently if scientists detect rising biotoxin levels or if an area seems to be more “dynamic” for red tide conditions. If an outbreak happens in late fall, testing may be done through the winter, when the mollusks’ metabolisms slow down and it takes longer for the toxins to leach out of their systems.

Scientists routinely check all areas where mussel, clam and quahog harvesters are known to operate, Couture said. The state frequently works with harvesters, dealers and restaurants to make sure the bivalve mollusks brought to shore are not contaminated.

Testing is done throughout each week by about a dozen or so scientists at DMR laboratories in Lamoine and Boothbay, she said. The shellfish are shucked, blended and mixed with acid to simulate the human digestive tract. Next, they are cooked and the solids and liquids are separated.

Samples of the liquids then are injected into mice – the only testing method allowed by law, according to Couture – to see whether there are any adverse effects on the rodents. Each sample is injected into three mice to make sure any reaction can be attributed to the shellfish.

“We do about 5,000 [tests] statewide each year,” Couture said. “We have a really good program, and people should never be afraid to eat seafood from a certified dealer or a restaurant.”

BDN writer Toni-Lynn Robbins contributed to this report.