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. There are also dozens of reported incidents of pathogens like e. coli and salmonella being found in this product, making it something that should NOT be fed to school children.
Further, experts like microbiologist Carl Custer, who worked at the Food Safety Inspection Service for 35 years, has been quoted (in the Huffington Post) as saying, "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."