Nebraska Beef Ltd. expanded a recall announced earlier this week to include all 5.3 million pounds of meat the firm produced for ground beef between May 16 and June 26.

Federal investigators have linked Nebraska Beef's products to an outbreak of E. coli illnesses that has now sickened 40 people in Michigan and Ohio.

The USDA's Food Safety and Inspection Service said in a statement Thursday that it has determined these products may have been produced "under insanitary conditions."

All of the beef being recalled was sold to wholesalers and distributors for further procession, so product labels likely will not include the "EST 19336" code that identified Nebraska Beef.

Some of Nebraska Beef's products were sold by grocer Kroger Co.

For a list of the products subject to recall, click here.