So, I was trying to figure out what “hamburger meat filler” meant when we were watching Food Inc., and I have a reliable source. It’s actually in a story that was in the New York Times only a few weeks ago:

With the U.S.D.A.’s stamp of approval, the company’s processed beef has become a mainstay in America’s hamburgers. McDonald’s, Burger King and other fast-food giants use it as a component in ground beef, as do grocery chains. The federal school lunch program used an estimated 5.5 million pounds of the processed beef last year alone.

Some sources I’ve seen say it’s in 70% of burgers sold in the US (especially fast food and school lunches), but I haven’t been able to confirm that number yet. Why use it in school lunches?

Despite some misgivings, school lunch officials say they use Beef Products because its price is substantially lower than ordinary meat trimmings, saving about $1 million a year.

Yikes. Here’s one bit of the Times story that jumped out at me, though:

Carl S. Custer, a former U.S.D.A. microbiologist, said he and other scientists were concerned that the department had approved the treated beef for sale without obtaining independent validation of the potential safety risk. Another department microbiologist, Gerald Zirnstein, called the processed beef “pink slime” in a 2002 e-mail message to colleagues and said, “I do not consider the stuff to be ground beef, and I consider allowing it in ground beef to be a form of fraudulent labeling.”