The beef product known as "pink slime" has been under fire lately. Most recently, parents have been pressuring public school districts to stop serving kids ground beef containing the controversial filler. In response, the U.S. Department of Agriculture said it would begin offering schools alternatives to meats containing "pink slime." Supermarkets like Albertsons and Safeway are promising to pull the product from shelves, and three plants where it is made are suspending production. Is "pink slime" really as bad as consumers think? Here's what you should know:

What is "pink slime"?
It's a filler added to ground beef. To make it, meat trimmings are spun in a centrifuge to separate separate beef from fat, a process similar to the technique used to get cream from milk. But the resulting "slime" is often contaminated with dangerous bacteria, such as E. coli, so the product is treated with ammonium hydroxide to raise pH levels and kill the bad stuff.

Why do we use it?
"Pink slime" — or, as the American Meat Institute calls it, "boneless lean beef trimmings (BLBT) — is added to regular ground beef to keep costs down. The meat industry touts it as a way to let humans benefit from excess meat that once was either discarded or turned into pet food. "The beef industry is proud to efficiently produce as much lean meat as possible from the cattle we raise," says the American Meat Institute. "It's the right thing to do and it ensures that our products remain as affordable as we can make them while helping to feed America and the world." 

Is ammonium hydroxide dangerous?
The levels used to treat the beef "are not close to toxic," says Ari Levaux at The Atlantic, "but they still smell and taste foul, tempting processors to go light on the treatment to make the product more palatable." Some evidence suggests that the alternative — not using ammonium hydroxide-treated beef altogether — might actually do more harm than good. When levels of the chemical were lowered after complaints of the ammonia's smell in 2009, "several batches of burger destined for school lunches" tested positive for E. coli and Salmonella. 

Should we really stop using "pink slime"?
That's debatable. Critics say anything that needs to be treated with ammonia hydroxide gas doesn't belong on our plates. But the American Meat Institute touts BLBT as a "safe, wholesome, and nutritious form of beef." Even the Center for Science in the Public Interest, a staunch consumer advocacy group, tells the Los Angeles Times the fuss is a "tempest in a teapot." The bottom line is that "pink slime" isn't any worse than the stuff you'd find in "yellow nuggets, brown breakfast sausage patties, or any number of mystery meat products," says The Atlantic's Levaux. "And for what it's worth, it isn't even slimy."

Sources: The AtlanticCBS NewsLos Angeles Times, The New York Times, Winnipeg Free Press