Earlier this year, McDonald’s made headlines when it said it would stop using ammonia-treated beef trimmings lovingly known as “pink slime” in its burgers. Now the former USDA scientist who coined the phrase is speaking out against the widespread use of the stuff — not because it’s unsafe, but because he feels like consumers are being deceived into paying for cheap filler.

“It’s economic fraud,” the scientist explains, adding that you’ll find pink slime in 70% of ground beef you buy at the supermarket. “It’s not fresh ground beef. … It’s a cheap substitute being added in.”

ABC News gives the general details of slime production:

The “pink slime” is made by gathering waste trimmings, simmering them at low heat so the fat separates easily from the muscle, and spinning the trimmings using a centrifuge to complete the separation. Next, the mixture is sent through pipes where it is sprayed with ammonia gas to kill bacteria. The process is completed by packaging the meat into bricks. Then, it is frozen and shipped to grocery stores and meat packers, where it is added to most ground beef.

The former USDA scientist and a colleague had warned regulators against the use of the filler, calling it “a salvage product … fat that had been heated at a low temperature and the excess fat spun out.”

But USDA chiefs didn’t heed the scientists’ concern: “The undersecretary said, ‘it’s pink, therefore it’s meat,'” one of them tells ABC.

70 Percent of Ground Beef at Supermarkets Contains ‘Pink Slime’ [ABC News]

Want more consumer news? Visit our parent organization, Consumer Reports, for the latest on scams, recalls, and other consumer issues.