SEATTLE – Attorney Bill Marler specializes in food safety cases, and the recent recall of 5.7 million pounds of meat has opened his eyes.

"What's happening right now is very concerning to me," said Marler.

The recall is the largest since the ConAgra E.coli outbreak of 2002. Marler says it has all the signs of a national emergency.

"It appears what they did is wait for people to get sick so the meat produced during that time frame and it either was tested or not tested before it was shipped and there's all sorts of arcane rules about why some meat gets tested and other meat does not get tested," said Marler.

Last Friday, the United Food Group based out of California expanded its earlier recall to include frozen and fresh beef products produced between April 6 and April 20 under the brand names of Moran's all natural, Miller Meat Company, Stater Brothers, Trader Joe's Butcher Shop, Inter-American Products and Basha's.

In Washington State, the beef was sold at Albertson's and Grocery Outlet under the brand names of Moran's, State Brothers, and Inter-American products.

In addition, the recalled products were shipped to stores in Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Utah and Wyoming. The affected grocery stores included Albertson's, Basha's, Grocery Outlet, Fry's, "R" Ranch Markets, Save-A-Lot, Save-Mart, Scolari's Wholesale Markets, Smart and Final, Smith's, Stater Bros. and Superior Warehouse.

More than 50 people have reportedly become ill. E. coli is a potentially deadly bacterium that can cause stomach cramps and diarrhea that may turn bloody. E. coli can sometimes lead to complications including kidney failure.

Marler says manufacturers began testing meat before it went out after the ConAgra outbreak.  A system was put in place which mandates all meat should be tested for E.coli before being sent out.

Marler does not have a reason for the latest outbreak, but he has a theory.

"It was either tested or not tested before it was shipped."

This most recent strain of E.coli is very difficult to cook out of the meat.  Marler suggests consumers return or throw away all beef bought from mid-April through mid-May.

"I would not eat it, under any circumstances."

Dietitians warn there is only one sure way to make sure you're not eating contaminated beef.

"Cook at 160 degrees and make sure no pink in the center," said Carolyn Snyder of the Cleveland Clinic.

None of the contaminated beef is still on store shelves. Customers with questions about the recall can call United Food Group's hot line at 1-800-325-4164. Those with recalled products should either throw the product away or return it to the point of purchase for a refund.

The Associated Press contributed to this report