A multi-state E. coli outbreak that has sickened at least 19 people who ate rotisserie chicken salad sold at Costco Wholesale Corp's (COST.O) stores has been traced to a celery-and-onion mix used in the salad, prompting its California maker to recall the product.

Shoppers are pictured outside a Costco Wholesale store in Los Angeles, California March 6, 2013.

The recall notice, posted on Thursday on the website of the U.S. Food and Drug Administration, said a sample of the diced vegetable blend examined by Montana state health authorities tested positive for the E. coli O157:H7 strain behind the recent outbreak.

The same strain, which can cause serious gastrointestinal illness, especially in young children and the elderly, is perhaps most often associated with the 1993 outbreak that killed four children who ate undercooked hamburgers at Jack in the Box fast-food restaurants.

At least five of the 19 people who have fallen ill this month have been hospitalized. Although no deaths have been reported, two individuals developed hemolytic uremic syndrome, or HUS, a type of kidney failure that can lead to permanent organ damage.

Infections have been reported in Montana, Utah, Colorado, California, Missouri, Virginia and Washington state, according to the federal Centers for Disease Control and Prevention in Atlanta.

Taylor Farms Pacific Inc, based in the San Joaquin Valley town of Tracy, California, is a major producer of fresh-cut vegetables and bagged salads.

"Out of an abundance of caution," the company said it was recalling more than 154,000 lots of numerous products from various grocery store chains in 17 states, most of them in the West.

Costco said it stopped selling the chicken salad in question on Nov. 20, the same day it was notified by federal health officials that it was linked to the E. coli cases, the company said.

Costco last year was linked to a salmonella outbreak caused by chicken products it sold in at least nine states. The contaminated chicken in that case was supplied by California-based Foster Poultry Farms.

The latest E. coli outbreak comes days after health officials linked burrito chain Chipolte Mexican Grill Inc. to more than 40 cases of E. coli O26 food poisoning in six states.

Reuters