Nine people in Washington, including two from Snohomish County and one from Island County, are believed to have become ill from eating alfalfa sprouts contaminated by salmonella bacteria, health officials said Thursday.

The illnesses are thought to have been caused by alfalfa sprouts from Sprouters Northwest Inc. in Kent, said Tim Church, a state Department of Health spokesman.

The company produces sprouts sold at many area grocery stores, including QFC, Safeway, Fred Meyer and Albertsons, he said.

The two people sickened in Snohomish County were a woman in her 20s and a teenage boy.

In addition to Snohomish and Island counties, people were sickened in Clark, King, Pierce, Thurston and Whatcom. At least two have been hospitalized, Church said. Four people in Oregon also became ill.

Health officials said people should not eat any products containing alfalfa spouts from Sprouters Northwest. They should either be discarded or returned to the store where they were purchased.

“This is a rare type of salmonella,” Church said. “That’s the main reason we believe they’re connected.” Of the nine people who became ill in Washington, six remembered eating sprouts from Sprouters Northwest, he said.

With this type of salmonella and so many people knowing that they ate this kind of sprout, “we’re convinced that the illness is connected to these sprouts,” Church said.

Symptoms of people infected with the food-borne illness include severe or bloody diarrhea, fever, chills, abdominal discomfort and occasionally vomiting, according to health officials.

Health officials say the infection can cause serious bloodstream infections, particularly in the very young or elderly.

The state health agency worked on the investigation with the state agriculture department, Oregon health officials and the federal Food and Drug Administration.

The first case was reported Aug. 1 and the most recent one was reported Aug. 20, Church said.

Sprouters Northwest is working with grocery stores to remove the product from their shelves. Company officials could not be reached for comment on Thursday.

Sprouters Northwest is one of the major distributors of sprouts in the Northwest, Church said.

On average, about 70 cases of salmonella are reported in Snohomish County each year, said Suzanne Pate, Snohomish Health District spokeswoman.

Sprouts are an inherently risky food because they require a moist and warm growing environment, “which is a great growing medium for bacteria as well,” she said.

Reputable producers go to great lengths to ensure the safety of their spouts by rinsing the seeds in antibacterial solutions before they are sprouted, she said.

But since there’s no way to guarantee that every spout product is safe, elderly people and those with weakened immune system should not consume them, she said.

Reporter Sharon Salyer: 425-339-3486 or salyer@heraldnet.com.