SEATTLE » Chipotle closed 43 of its Pacific Northwest locations after the chain’s third foodborne illness this year sickened about two dozen people — prompting renewed scrutiny of a company that touts its use of fresh ingredients and farm-sourced fare.

Cases of the bacterial illness were traced to six of the casual Mexican food restaurants, but the company voluntarily closed down all of its locations in Washington and the Portland, Oregon, area as a precaution as an investigation continues.

Three people in the Portland area and 19 people in western Washington have gotten sick with E. coli as of Friday. Seventeen of them had eaten at a Chipotle restaurant during the past few weeks. Eight people have been hospitalized but no deaths have been reported.

About a dozen more people were being tested for E. coli on Monday in Washington state and health officials were aggressively searching for more cases, said Dr. Scott Lindquist, state epidemiologist for communicable diseases for the Washington State Department of Health.

Lindquist does not expect the number of sick people to increase dramatically, and he said they are not positive yet that the outbreak is limited to people who ate at Chipotle restaurants over the past few weeks.

Those sickened in the E. coli outbreak range in age from 11 to 61. Lindquist did not have any detailed information about their medical conditions.

A lawsuit was filed against the company Tuesday by a Washington woman who alleges she contracted an E.coli infection after eating a burrito bowl on Oct. 21 in a Chipotle restaurant in Vancouver.

Minneapolis law firm PritzkerOlsen filed the lawsuit on behalf of Charmaine Mode in U.S. District Court in Western Washington. Documents say she sought treatment Oct. 27 and was diagnosed after falling ill on Oct. 25 with nausea, severe diarrhea and other symptoms.

Chipotle has faced other recent foodborne outbreaks. A salmonella outbreak linked to tomatoes sickened dozens of people in Minnesota beginning in August, according to state health officials. In California, health workers said norovirus sickened nearly 100 customers and employees at a Chipotle restaurant in Simi Valley in mid-August.

“Having three problems in a couple of months means that Chipotle is not paying attention to food safety like it should,” said Bill Marler, a Seattle food safety lawyer who built his national reputation with the 1993 E. coli outbreak at Seattle Jack in the Box restaurants.

The common denominator in most food-borne illness outbreaks is poor food safety, Marler said.

People should not assume a company that focuses on local and fresh ingredients — like Chipotle — is going to be immune from food safety issues, he said.

“People shouldn’t have a false sense of security that local means safer,” Marler said.

Health officials believe the contamination at Chipotle is related to a fresh food product such as lettuce or other produce.

The outbreak probably will not be traced to one sick individual or one instance of cross-contamination of food because the cases are connected with various restaurants, said Marisa D’Angeli, medical epidemiologist with the Washington State Department of Health.

The company is not planning to close any other restaurants in other states because there is no evidence of a link to other locations, company spokesman Chris Arnold said.

Only six restaurants in Washington and Oregon have been connected to the outbreak.

“We closed 43 in those states out of an abundance of caution,” Arnold said.

Reopening the shuttered locations will depend on the investigation, he said.

Allen Adamson of New York marketing consulting firm BrandSimple said the outbreak in Washington state is likely to hurt the brand far beyond the closed stores.

“Many consumers will feel, ‘Why risk it?,’ until they find out how it happened,” Adamson said. “Consumers have lots of choices.”

Although the shutdown restaurants represent just 2 percent of the company’s 1,931 locations, each restaurant brings in about $2.5 million in revenue a year on average, according to Chipotle.

Chipotle’s stock fell as much as 5 percent early Monday, but recovered slightly, falling 2.5 percent to close at $624.

The decision to close down immediately will help the brand in the long-term, said Laura Ries, president of Atlanta marketing strategy firm Ries & Ries. “They went above and beyond what they needed to do,” she said.

Customers tend to return to eating foods that caused illnesses as soon as they are assured it’s safe, said Darren Seifer, a food analyst at market research firm NPD Group.

Chipotle’s stock fell as much as 5 percent early Monday, but recovered slightly, and was down about 3 percent by Monday afternoon.

Outside a closed Chipotle near the University of Washington in Seattle, Trey Reche stopped by to read the signs on the door.

“I think Chipotle has too much of a strong fan base to go completely under by this,” said Reche, who last ate at Chipotle a few weeks ago. “It might be a huge wakeup call for them to rethink how they’re getting their food.”

___

AP writers Manuel Valdes in Seattle and Joseph Pisani in New York contributed to this report.