LOS ANGELES (Reuters) - Chipotle Mexican Grill Inc is now linked to 12 confirmed cases of E. coli food poisoning in Oregon, state health officials said on Tuesday.

One-fourth of the cases have involved hospitalizations, Oregon Health Authority officials said.

Health department officials over the weekend said there were 19 cases in Washington and three in Oregon. Eight involved individuals who had been hospitalized.

Washington is expected to issue an update later on Tuesday.

The outbreak is Chipotle's third food-safety incident this year. Investigators are searching for the source of the contamination and suspect it involves fresh produce.

Health officials have urged anyone who ate at Chipotle restaurants in the two states between Oct. 14 and Oct. 23 and suffered vomiting and bloody diarrhea to see their healthcare provider. They expect the number of reported cases to rise as news of the outbreak spreads.

A woman sued Chipotle in federal court in Washington state on Monday, saying that she was infected with the food-borne illness as a result of a meal at the popular burrito chain, which has closed 43 restaurants in Washington and Oregon amid the outbreak of E. coli O26.

Charmaine Denise Mode, of Kelso, Washington, ate a burrito bowl at the Vancouver Chipotle on or about Oct. 21 and is seeking more than $75,000 in damages, the lawsuit said.

A few days her meal at the restaurant, Mode felt nauseated, had severe diarrhea, and sought medical treatment on Oct. 27 at a clinic in Longview, Washington, the lawsuit said. It added that she had tested positive for the E. coli linked to the outbreak.

A Chipotle representative declined to comment, saying the company does not discuss pending legal actions.

Company shares were up 0.7 percent at $628.46 on Tuesday after touching their lowest level since July a day earlier.