According to ABC the USDA does not require "boneless lean beef trimmings" to be listed as an added ingredient to ground beef. Since boneless lean beef trimmings are processed from beef they need not be listed separately. ABC reports that pink slime trimmings were "once only used in dog food and cooking oil." The report describes the manufacturing process:
The “pink slime” is made by gathering waste trimmings, simmering them at low heat so the fat separates easily from the muscle, and spinning the trimmings using a centrifuge to complete the separation. Next, the mixture is sent through pipes where it is sprayed with ammonia gas to kill bacteria. The process is completed by packaging the meat into bricks. Then, it is frozen and shipped to grocery stores and meat packers
Got me wondering about hamburger patties used by restaurants and fast food chains. Googled the question - USA Today reports that some fast food chains decided in January to stop using pink slime because of the bad PR, but the USDA still uses it for the school lunch program.
While Mr. Spock would certainly argue that considering pink slime to be "beef" is logical as it is made from livestock components with no additives other than a dash of ammonia, and even though I have no problem eating hot dogs or scrapple, I'm thinking its about time to buy a grinder attachment for the ol' Hobart mixer.