Kroger Co., the biggest grocery store operator in the U.S., extended last week its voluntary recall of all ground beef products sold in Michigan and certain Ohio stores in the May 21 - June 8 period after the U.S. Department of Agriculture identified the supplier as Nebraska Beef Ltd.

This is because the meat has been associated to a recent outbreak of illnesses caused by contamination with E. coli bacteria. Kroger said on Tuesday the recall now includes ground-beef products in Styrofoam tray packages enwrapped in clear cellophane or purchased from an in-store service counter in certain stores. The company is also recalling Private Selection Natural ground beef, which was available at all Kroger stores, sold in 16-ounce packages with "sell-by" dates July 11 to July 21 from the self-service meat case.

The product was available at Dillons, Fred Meyer, Baker's, Smith's and Fry's. In addition, some Ralphs supermarkets in Hollywood, Silver Lake and Orange County on Tuesday pulled ground beef off their shelves in response to the Nebraska beef recall. The expanded recall comes after the U.S. Department of Agriculture’s Food Safety and Inspection Service, or FSIS, informed the company that Nebraska Beef had been identified as the supplier of ground beef products connected to E. coli illnesses in Michigan and central and northern Ohio.

Federal government investigators traced the meat to Nebraska Beef after 38 people in Ohio and Michigan became ill.

Customers should check if they bought meat at Fred Meyer or QFC stores with "sell-by" dates between May 21 and July 5 or at Kroger stores between May 21 and July 3.

Kroger stores in Georgia, South Carolina, Alabama, and Knoxville, Tenn. are not involved.

Customers should check if they purchased meat in Kroger's Mid-Atlantic division, which includes stores in North Carolina, Northeastern Tennessee, Virginia and West Virginia with "sell-by" dates between May 19 and June 6.

Other meat being recalled includes these stores and “sell-by” dates: Fry's _ May 21 to July 3; Ralphs _ May 21 to July 3; Smith's _ May 21 to July 3; Baker's _ May 17-June 4; King Soopers _ June 20-July 3; City Market _ June 20-July 3

For customers who shop at Hilander, Owen's, Pay Less, and Scott's are available for check-up the "sell-by" dates listed above for Kroger stores.

The meat purchased from Kroger stores and Kroger authorized stores can be returned to them for a full refund and replacement.