A recall stemming from an E. coli scare at Costco now spans more than a dozen states and includes products sold at major grocery chains, including Walmart, Safeway and Albertsons.
It does not affect the New York and New Jersey areas.
Contaminated celery from California-based Taylor Farms Pacific was found to be the source of Costco's chicken salad recall last week.
The Food and Drug Administration expanded the recall of food products on Tuesday to include 155,000 items such as salad kits, vegetable trays and other prepared foods.
Among the stores involved are Walmart, Sam's Club, Costco, Albertsons, 7-Eleven, Target and Safeway.
The products were primarily distributed in Western states, but stores in states including Georgia, Arkansas, Nebraska and Hawaii are also affected.
Symptoms of E. coli infection include diarrhea, abdominal cramps, nausea and vomiting. The incubation period is three to seven days from the time of exposure.
The spread of foodborne illness takes time to track, especially when it's happening in multiple states, said Dr. Robert Tauxe, deputy director of the CDC's Division of Foodborne, Waterborne and Environmental Diseases.
State health officials, particularly those in Utah, discovered the outbreak and helped find the links between the 19 illnesses in seven states, Tauxe said.
"Very quickly they noticed these people did have something in common. They really liked and ate the rotisserie chicken salad," he said.
The CDC has identified a DNA fingerprint of the E. coli strain connecting all 19 patients. As health departments get more reports of foodborne illness, additional people will be checked for the fingerprint and the case count will likely rise, Tauxe said.
The CDC said the illness reports began on Oct. 6 and involved people from age 5 to 84.