Sept 13 (Reuters) - Beef Products Inc is planning to file a defamation lawsuit over a product that critics have dubbed "pink slime," in the wake of a media furor earlier this year. The Dakota Dunes, South Dakota-based company said it planned to publicly discuss the lawsuit later Thursday. It did not identify any defendants or specific allegations. Beef Products is the largest U.S. producer of a lean ground beef filler made from fatty trimmings. The trimmings are sprayed with ammonia to kill bacteria. While the filler has long met federal food safety standards, critics have questioned its safety, and companies such as McDonalds Corp and supermarket chain Safeway Inc stopped buying the product.. Beef Products this year shut three of its four plants and eliminated about 650 jobs, blaming the media furor for the cuts.