"Pink slime," a cheap meat filler, is in 70 percent of the ground beef sold at supermarkets and up to 25 percent of each American hamburger patty, by some estimates.
"It kind of looks like play dough," said Kit Foshee, who was a corporate quality assurance manager at Beef Products Inc., the company that makes pink slime. "It's pink and frozen, it's not what the typical person would consider meat."
As seen in the movie Food Inc., the low-grade trimmings come from the most contaminated parts of the cow and were once only used in dog food and cooking oil. But because of BPI's treatment of the trimmings - simmering them in low heat, separating fat and tissue using a centrifuge and spraying them with ammonia gas to kill germs - the United States Department of Agriculture says it's safe to eat.
If you have questions about "pink slime," email us at ABC.WorldNews@abc.com.
The company calls the final product "Finely Textured Lean Beef." It is flash frozen and boxed. Foshee says it is more like gelatin and not nutritious as ground beef because the protein comes mostly from connective tissue, not muscle meat.
"[It will] fill you up, but won't do any good," Foshee said.
ABC News was flooded with questions from concerned viewers following last night's report on pink slime.
Many, like Dale Rittenhouse, wanted to know where beef with pink slime was sold.
"What stores use pink slime?" Rittenhouse wrote.
So ABC News producers traveled across the country to the meat section to see if its in the ground beef they sell. Most couldn't tell us for sure.
"There is no way to even know from labels or even from the butchers here whether it contains pink slime," said ABC News producer Candace Smith in New York.
"The guy at the meat counter said that he had been getting the same question all day," said Janice McDonald in Atlanta.
ABC News emailed the top 10 grocery chains in America. Only Publix, Costco, HEB and Whole Foods responded, saying they don't use pink slime. No word yet from the rest.
A viewer, Miles Herbert, wanted to know, "Is there any evidence that organic meat contains this pink slim?"
It turns out there isn't. If your meat is stamped USDA Organic, it's pure meat with no filler.
But critics say everything else is suspect because pink slime does not have to appear on the label. And the USDA is giving no indication it will force meat packers to lift the veil of secrecy any time soon.