Nebraska Beef Ltd. is expanding a recall announced earlier this week to include all 5.3 million pounds of meat 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 sickened 40 people in Michigan and Ohio.

The USDA's Food Safety and Inspection Service said in a statement Thursday that it concluded Nebraska Beef's production practices were insufficient to effectively control E. coli.

"The products subject to recall may have been produced under insanitary conditions," the government said.

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. Kroger has recalled ground beef products sold in its stores in more than 20 states because the meat may have been contaminated with E. coli.

On Monday, Nebraska Beef announced plans to recall 531,707 pounds of beef trim produced on five different dates between May 16 and June 24.

Now the recall includes all beef trimmings and other products intended for use in ground beef produced at the plant between May 16 and June 26.

The company said Monday that beef involved in the original recall went to businesses in Nebraska, Colorado, Illinois, Michigan, New York, Pennsylvania and Texas.

Thursday's release did not specify whether the 5.3 million pounds now being recalled went to any additional states.

Nebraska Beef spokesman Bill Lamson did not immediately respond to a message left Thursday afternoon.

The company's Omaha plant typically slaughters about 1,000 head of cattle a day.

Cooking ground beef to an internal temperature of at least 160 degrees should kill any E. coli bacteria that is present. The USDA recommends that consumers use a meat thermometer to verify that temperature when cooking.

The E. coli 0157:H7 variant can cause severe illness and even death in humans. Symptoms of E. coli infection include stomach cramps and diarrhea that may turn bloody within one to three days.

The federal Centers for Disease Control and Prevention estimates that E. coli sickens about 73,000 people and kills 61 each year in the United States. Most of the deaths are people with weak immune systems such as the elderly or very young.