A Colorado company's recall last week of beef products possibly contaminated with E. coli has been expanded, the U.S. Department of Agriculture said this week.

The recall came as a result of "an ongoing investigation into 24 illnesses in multiple states," the USDA said.

The initial recall of 41,280 pounds announced last Wednesday was voluntarily expanded Sunday to include an additional 380,000 pounds of products made by the JBS Swift Beef Company, of Greeley, Colorado, the USDA said.

The recall came as a result of "an ongoing investigation into 24 illnesses in multiple states, of which at least 18 appear to be associated," the USDA's Food Safety and Inspection Service said in a written statement.

USDA spokesman Brian Mabry said no fatalities had been reported.

On its Web site, the company said the suspect beef was produced at its Greeley plant on April 21 and distributed nationally and internationally.

Boxes of the recalled product bear the establishment number "EST. 969" inside the USDA mark of inspection, the identifying package date of "042109" and a time stamp ranging from "0618" to "1130," the statement said. It added that some of the beef products might have undergone further processing and might not have the "EST. 969" marking on products for sale directly to consumers.

The USDA urged any customers with concerns to contact the store where they bought the meat.