Pink slime -- that ammonia-treated meat in a bright Pepto-bismol shade -- may have been rejected by fast food joints like McDonald's, Taco Bell and Burger King, but is being brought in by the tons for the nation's school lunch program.

The U.S. Department of Agriculture is purchasing 7 million pounds of the "slime" for school lunches, The Daily reports. Officially termed "Lean Beef Trimmings," the product is a ground-up combination of beef scraps, cow connective tissues and other beef trimmings that are treated with ammonium hydroxide to kill pathogens like salmonella and E. coli. It's then blended into traditional meat products like ground beef and hamburger patties.

"We originally called it soylent pink," microbiologist Carl Custer, who worked at the Food Safety Inspection Service for 35 years, told The Daily. "We looked at the product and we objected to it because it used connective tissues instead of muscle. It was simply not nutritionally equivalent [to ground beef]. My main objection was that it was not meat."

Custer and microbiologist Gerald Zernstein concluded in a study that the trimmings are a "high risk product," but Zernstein tells The Daily that "scientists in D.C. were pressured to approve this stuff with minimal safety approval" under President George H.W. Bush's administration. The USDA asserts that its ground beef purchases "meet the highest standard for food safety."

Controversy surrounding "pink slime" stems from various safety concerns, particularly dangers associated with ammonium hydroxide, which can both be harmful to eat and has potential to turn into ammonium nitrate -- a common component in homemade bombs, according to MSNBC. It's also used in household cleaners and fertilizers.

In 2009, The New York Times reported that despite the added ammonia, tests of Lean Beef Trimmings of schools across the country revealed dozens of instances of E. coli and salmonella pathogens.

Between 2005 and 2009, E. coli was found three times and salmonella 48 times, according to the Times, including two contaminated batches of 27,000 pounds of meat.

A public outcry against the "slime" is led perhaps most prominently by celebrity chef Jamie Oliver, who had also successfully waged war against flavored milk in Los Angeles schools and continues a crusade for healthier school lunches.

News of the USDA's plan to bring 7 million pounds of "pink slime" to school cafeterias nationwide comes just weeks after the government announced new guidelines to ensure students are given healthier options for school meals. The new standards call for more whole grains and produce as well as less sodium and fat in school meals. While the measures mark a step forward from previous years, they still compromise amid push-back from Congress to keep pizza and french fries on the menu -- counting both the tomato paste on pizza and the potatoes that make fries as vegetables.

Still, some schools -- like several in California -- have taken the matter into their own hands, and have found ways to profit from those efforts. Umpteen school districts have taken part in a decade-long initiative, supported by a philanthropic organization, that provides schools with equipments and chefs who teach cafeteria workers to cook from scratch and produce fresh meals.

A recent report by the Centers for Disease Control and Prevention revealed that more than a third of high school students were eating vegetables less than once a day -- "considerably below" recommended levels of intake for a healthy lifestyle that supports weight management and could reduce risks for chronic diseases and some cancers.