When McDonald’s and other fast-food chains announced last month that the infamous “pink slime” was no longer being used in their burgers, some thought the ammonium hydroxide-treated beef cuts had disappeared from our food supply once and for all.

Raw beef. (Jahi Chikwendiu/WASHINGTON POST)

The USDA, schools and school districts plan to buy the treated beef from Beef Products Inc. (BPI) for the national school-lunch program in coming months. USDA said in a statement that all of its ground beef purchases “meet the highest standard for food safety.” The department also said it had strengthened ground beef safety standards in recent years.

Last April, celebrity chef Jamie Oliver reported that 70 percent of America’s ground beef is made with BPI’s ammonia-treated product.

BPI recently said that figure still holds. In a statement, the company called ammonium hydroxide a “natural compound ... widely used in the processing of numerous foods.”

Gerald Zirnstein, a former microbiologist at the Food Safety Inspection Service who coined the term “pink slime,” told the Daily that the continued purchase of ammonium hydroxide-treated beef cuts for school lunches doesn’t make any sense.

“I have a 2-year-old son,” he told the Daily. “And you better believe I don’t want him eating pink slime when he starts going to school.”

Zirnstein came up with the “pink slime” phrase when he toured a Beef Products Inc. production facility in 2002 during an investigation into salmonella contamination in packaged ground beef. After the animal byproduct is mixed with ammonia, it has a pink appearance. Zirnstein e-mailed his colleagues after the visit to say he did not “consider the stuff to be ground beef,” according to the Daily.

Change.org has a petition up on its site asking USDA to stop buying the slime. Launched by Houston-based “The Lunch Tray” blogger Bettina Siegel, the petition says that “it is simply wrong to feed our children connective tissues and beef scraps that were, in the past, destined for use in pet food and rendering and were not considered fit for human consumption.”

The Food and Drug Administration, as well as the Food Safety and Inspection Service, however, consider ammonium hydroxide to be “generally recognized as safe.” 

The ammonium treatment process was initially touted as capable of killing E. coli as well as salmonella in meat. But a 2009 New York Times report said the process didn’t seem to be working:

Government and industry records obtained by The New York Times show that in testing for the school lunch program, E. coli and salmonella pathogens have been found dozens of times in Beef Products meat, challenging claims by the company and the U.S.D.A. about the effectiveness of the treatment. Since 2005, E. coli has been found 3 times and salmonella 48 times, including back-to-back incidents in August in which two 27,000-pound batches were found to be contaminated. The meat was caught before reaching lunch-rooms trays.

In a recent letter to consumers, sent out after McDonald’s discontinued use of its meat, BPI said that the company had a stellar food safety record.

“We were pleased earlier this year to have been placed on the ‘nice list’ by noted food safety advocate Bill Marler and to add that to the other recognition we have received for those food safety efforts. We maintain an unsurpassed food safety record and at times have been a part of nearly 20 billion meals annually, without ever being the source of a foodborne illness.”

The company also shared a YouTube video with consumers, which reiterated that ammonia is “essential for life,” is naturally found in beef and is widely used in processing.