The threat of a possible E. coli contamination has promped the recall of two brands of Romaine lettuce.
Freshway Foods has recalled the Freshway and Imperial Sysco brands in 23 states and the District of Columbia.
The move comes after an E. coli outbreak sickened 19 people in Ohio, New York and Michigan. According to an Associated Press report, three of them had life-threatening symptoms.
The Food and Drug Administration said Thursday that 12 people had been hospitalized and the federal Centers for Disease Control and Prevention said it was looking at 10 other cases probably linked to the outbreak.
A New York state lab discovered the virus in a bag of shredded romaine lettuce distributed by the company.
Freshway Foods said in a statement Thursday that the FDA informed the company about the positive test in New York on Wednesday afternoon. The statement said "an extensive FDA investigation" of Freshway Foods' facility in Sidney has not uncovered any contamination at the plant.
State health departments have reported that college students attending the University of Michigan in Ann Arbor, Ohio State in Columbus and Daemen College in Amherst, N.Y., were among those who were sickened.
Susan Cerniglia, spokeswoman for the public health department in Washtenaw County, where the University of Michigan is located, said it doesn't appear that students who were sickened ate the contaminated food on campus. It is believed they may have been sickened at local restaurants, she said.
The recalled lettuce has a "best if used by" date of May 12 or earlier. The recall also affects "grab and go" salads sold at Kroger, Giant Eagle, Ingles Markets and Marsh grocery stores.
The lettuce was sold in Alabama, Connecticut, the District of Columbia, Florida, Georgia, Illinois, Indiana, Kansas, Kentucky, Maryland, Massachusetts, Michigan, Missouri, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, South Carolina, Tennessee, Virginia, West Virginia and Wisconsin.
The Associated Press contributed to this report.