SAN FRANCISCO (AP) — 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 Inc. of Tracy, California, has recalled a mix of diced celery and onion used in Costco chicken salad and other foods containing celery "out of an abundance of caution," the Food and Drug Administration said in a statement Thursday.The foods range from Thai-style salads to packaged dinners and wraps, and they are sold at Costco, Target, Starbucks and many other outlets, the FDA said.Costco says it uses one supplier for those vegetables in the chicken salad sold in all its U.S.