CLEVELAND -- A massive ground beef recall is causing concern just days before the holiday weekend.

Health experts say the meat could contain E. coli. They say it's the type of strain that worries them the most.

"It can release a toxin into the blood that attacks the kidneys and frequently can cause life-threatening illnesses for young children," said Caroline Smith with the Center for Science in the Public Interest.

Already 11 people have been sickened in four states -- Michigan, Missouri, Ohio and Massachusetts.

LIST: Complete breakdown of recalled products

Detroit's Wolverine Packing Co. recalled nearly 2 million pounds of beef.

Locally, Kevin Brennan with the Cuyahoga County Board of Health says the meat went to two distributors -- Blue Ribbon Meats and Sysco.

The Health Department says the companies have contacted customers and are making sure the meat is destroyed.

In Portage County, the Kent City Health Department is investigating a suspected E. coli case from the meat.

The USDA says the suspected meat was not sold to schools.

It was produced between March 31 and April 18.

The company says "no product" tested positive for E. coli.

But health experts warn that cooking a burger medium-rare or medium may not be enough to keep you safe.

"Unfortunately, hamburger is never really considered safe unless it's thoroughly cooked. It can be tough like a hockey puck," said Smith.