CARLISLE, Pa. (AP) — Grocery chain Giant Food Stores on Thursday joined the growing number of food merchants that are halting sales of fresh ground beef containing the filler known as pink slime.

Giant Food Stores LLC, headquartered in Carlisle, cited questions and concerns raised by hundreds of its customers as the impetus for the move, which will affect the 144 Giant stores in the area and the 39 Martin’s food stores it owns in Maryland, Virginia and West Virginia.

“They felt that this was not something that they wanted to purchase so we decided we would not purchase it,” company spokesman Chris Brand said.

The switch to ground beef without the filler, known in the food industry as lean finely textured beef, will not occur overnight. It will take a few weeks to sell and replace the current inventory of beef, Brand said.

“Obviously, there is product in the supply chain already” that will be sold first, he said.

In the meantime, shoppers unwilling to buy ground beef with the filler can buy prepackaged meat that does not contain it, he said.

Brand said that the U.S. Department of Agriculture has indicated the filler is safe for consumption and that many customers have expressed no concerns about it.

Several supermarket chains have taken similar steps as images, media reports and online petitions have heightened concern among consumers about pink slime, a term coined by a federal microbiologist grossed out by it and now widely used by critics and food activists.

The low-cost additive is made from fatty bits of leftover meat that are heated, spun to remove the fat, compressed into blocks and exposed to ammonia to kill bacteria. Producers often mix it with fattier meat to produce an overall leaner product and reduce their costs.

(Copyright 2012 by The Associated Press. All Rights Reserved.)