Chipotle Mexican Grill Inc. announced it has ran steps to improve food safety by hiring two food safety consulting firms, including IEH Laboratories and Consulting Group, to perform batch-testing ingredients as an effort to respond to its E. coli cases.

Chipotle was reported to be the cause of E. coli food poisoning cases in Washington and Oregon.

Epidemiologist Katrina Hedberg of the Oregon Health Authority told USA Today that there are 12 confirmed E. coli cases in Oregon this week.

The number raised from the three confirmed cases on the last weekend. At least eight of them became ill after eating at Chipotle. Although there have been no deaths, a third of those affected were hospitalized.

The Oregon Health Authority has been encouraging anyone who has eaten at Chipotle and has developed severe diarrhea or bloody diarrhea to seek health care.

Hedberg added that most of those who became ill in Oregon were from the Portland area and the number of case counts may increase.

The number of confirmed E. coli cases in Washington also rose to 25 cases from 19 cases last weekend.

A public health official in Washington reported that 23 of 25 sicken people ate at Chipotle.

Chipotle was forced to close 43 restaurants temporarily in the Pacific Northwest, in and around Seattle and Portland.

Eight of these restaurants are tied to the E. coli cases. The company has been deep cleaning and fully sanitizing the shuttered restaurants and replacing all food in them.

Chipotle co-Chief Executive Offices Steve Ells, according to Bloomberg, expressed his deepest sympathies to those who affected by this case. He said that the company works with a number of very fresh ingredients in order to serve the highest quality and best-tasting foods.

He added that the company will enhance its standards for food safety to ensure the safety of all food served at Chipotle.

The investigators are still searching for the source of the contamination cases. They suspect it involves fresh products.

However, health officer for public health for Seattle and King County Dr. Jeff Duchin told Reuters, that the source of the contamination is still difficult to determine since many of Chipotle's dishes include similar ingredients.

Meanwhile, a woman who ate at Chipotle in Vancouver has sued the restaurant as she began experiencing bloody diarrhea after eating at Chipotle.

She tested positive for shiga toxin producing E. coli. The lawsuit seeks $75,000 in damages. A Chipotle's spokesman declined to comment on the lawsuit.