Former U.S. Department of Agriculture scientist-turned whistleblower Gerald Zirnstein revealed a dirty little secret of the meat industry to ABC News: 70 percent of hamburger meat sold in grocery stores contains “pink slime,” a cheap and dangerous filler made of rejected beef trimmings that at one time were only used to make dog food and cooking oil. Pink slime is made from the least-desirable beef scraps, like connective tissue, tendons, and gristle. The scraps are ground up and simmered at low heat, then put in a centrifuge and spun to separate the fat from the meat. The resulting mixture is then sprayed with ammonia gas — ostensibly to to kill bacteria — then shaped into bricks, flash-frozen and shipped to grocers and meat packing companies where it is combined with ground beef. Understandably, the meat industry doesn’t like the name “pink slime.” It prefers to call the additive “lean, finely-textured ground beef.” Thanks to Joann Smith, USDA undersecretary under George W. Bush, pink slime doesn’t have to be labeled as a byproduct, either, and grocers don’t have to let consumers know it is in their meat. Smith made the decision to label the stuff “meat” against the urging of Zirnstein and another USDA scientist, Carl Custer, who call pink slime a “high risk product,” since the trimmings come from the most contaminated parts of many cows. In making her decision, Smith reportedly said that the mixture “is pink, therefore it’s meat.” While at USDA, Smith had ties to the beef industry. She was president of the Florida Cattlemen’s Association and the National Cattlemen’s Association. ABC News found out that after Smith left the USDA in 1993, the manufacturers of pink slime, Beef Products, Inc., appointed her to its board of directors, where she has since made around $1.2 million over 17 years. After their report on pink slime, ABC News was inundated with questions from viewers about how to avoid the substance at grocery stores. The answer? Look for meat stamped “USDA Organic.” It is pure meat that contains no fillers. Everything else could contain pink slime since the law doesn’t require it to be revealed on the label.