In this image released by Beef Products Inc., boneless lean beef trimmings are shown before packaging. The term ”pink slime” has been adopted by opponents of ”lean finely textured beef,” and describes the processed trimmings cleansed with ammonia and commonly mixed into ground meat. (AP/AP)

The low-cost beef additive that has come to be known as “pink slime” is quickly approaching its expiration date at hundreds of school cafeterias in the Washington region and beyond.

By next school year, most of the hamburgers, taco crumbles and breakfast patties served in public schools should be free from the ammonia-treated filler, school officials report. Public schools in Montgomery and Fairfax counties are joining districts in New York City, Miami-Dade and scores more across the country by canceling their orders of the meat byproduct, from private vendors and the federal agency that operates the National School Lunch Program.

The move away from the meat additive is being heralded by parent advocates for healthier school lunches.

“Our whole point is: What are we eating?” said JoAnne Hammermaster, founder of the Fairfax-based advocacy group Real Food for Kids. “We should not have stuff in there that we can’t pronounce and we don’t know if it’s harmful or not.”

The planned changes, made mostly in recent weeks, follow a wave of public scrutiny over processed beef and a decision this month by the U.S. Department of Agriculture to offer schools ground-beef products that do not contain the additive.

Officially called “lean finely textured beef,” the filler in question is a combination of beef scraps and connective tissue that is simmered at low heat and spun in a centrifuge to remove fat. It is then sprayed with ammonia gas to kill pathogens such as E. coli, and finally is frozen and distributed to be added to ground beef.

Federal regulators have long maintained that the product is safe to consume, and it has been widely used as a lean filler for ground beef. It is not required to be listed separately on food labels.

This year, the USDA has contracted to buy about 7 million pounds of the additive, constituting about 6 percent of the 112 million pounds of ground beef it plans to distribute nationally through the school lunch program. School districts get about 20 percent of their food donated from the federal government and purchase the rest from private vendors.

Officials in Arlington County, Alexandria, Prince George’s County and the District said that none of their private beef suppliers currently uses the additive. Loudoun County schools spokesman Wayde Byard that some of the beef it uses comes from the USDA and could contain the meat byproduct.

A growing outcry surrounding processed food has been buoyed by celebrity chefs including Jamie Oliver, who launched the Web site, along with a growing number of parents and foodies. McDonald’s and Burger King announced they would stop using the processed beef this year, and recently, grocery store chains, including Kroger and Safeway, have agreed to stop selling beef with the filler.

The outcry over the additive came swift and strong. On March 6, Houston-based blogger Bettina Seigel launched an online petition urging Agriculture Secretary Tom Vilsack to stop using “ ‘pink slime’ in our children’s school food.”

More than 250,000 parents signed on, and within two weeks, the USDA said it would allow school districts to choose whether to serve the meat byproduct.

Members of Congress have since asked the USDA to go further and eliminate it from the school lunch program completely.

“If pink slime-laced ground beef is less expensive to make, we are very concerned that lower funded districts will be forced to use it,” said a letter to Vilsack signed by 41 lawmakers. The result would in effect “create a two-tiered lunch program.”

Montgomery officials said that its inventory includes government-issued beef but that it will order meat without the filler as soon as it is available for the next school year. They also said that future contracts with private vendors will specify that the beef should be free from lean, finely textured beef or ammonium hydroxide.

Fairfax County schools do not use beef products purchased by the USDA. But beef patties provided to the district by one vendor, California-based Don Lee Farms, do contain the additive.

“The district’s plan is to finish off the current inventory of this product and to start serving 100 percent beef hamburger patties by the middle of next month,” Fairfax schools spokesman John Torre said.

Parents in Fairfax had already been advocating for the school system to banish its hamburger, which as of this year, contained at least two dozen ingredients, including caramel coloring and hydrolized soy protein.