SAN FRANCISCO — Federal officials say a business is recalling a vegetable mix believed to be the source of E.coli in Costco chicken salad that has been linked to an outbreak that has sickened 19 people in seven states.

Taylor Farms Pacific of Tracy, Calif., has recalled a mix of diced celery and onion used in Costco chicken “out of an abundance of caution,” the Food and Drug Administration said in a statement Thursday.