Beef Products Inc, the leading producer of the filler the industry calls "finely textured beef," opened its meat plant in South Sioux City, Nebraska in a remote area straddling Nebraska, Iowa and South Dakota.
The tour was part of an effort by the beef industry to fight consumer activists who have successfully campaigned to ban the beef filler from most supermarkets, fast food and school lunches.
Texas Governor Rick Perry, Kansas Governor Sam Brownback and Iowa Governor Terry Branstad -- wearing hard hats, white coats and munching on hamburgers during the visit -- said the bad rap on "pink slime" was an unwarranted food scare.
"When we have these false rumors that get started, they have the potential to take down an entire company. That really hits close to home," Perry said, adding that 650 workers had been idled by the scare, including 300 at a meat plant in Texas.
After being shown the examples of the fat-laden scraps up to 8 inches long in an adjacent conference room, the tour entered the gleaming plant, where workers kept watch on the automated process that churned out pink 60-pound blocks of the textured filler.
A reporter on the tour described the product as about as red as typical ground beef but with a less-coarse texture. Consumers, he was told, prefer the coarser texture, so the filler which the industry says is 98 per cent lean, is mixed in to make the beef sold on store shelves leaner.
The tour was organized as hundreds of US school districts demanded the beef filler be removed from school lunch programs, and the three largest US supermarket chains halted purchases of beef containing the filler. A regional grocery chain, Hy-Vee Inc., said it reversed a ban and would sell beef with and without the filler.
McDonald's stopped using hamburgers with the filler last year.
While the US Agriculture Department says the filler is safe to eat, this has not stopped a campaign by food activists, which gained traction when celebrity chef Jamie Oliver complained about it on his television show and showed pictures of unsightly globs of filler.
Beef Products took out newspaper ads featuring testimonials from health experts attesting to the product's safety. The governors were handed T-shirts printed with the slogan, "Dude, it's beef."
The tour was held at the last of Beef Products' four plants producing the filler remaining in operation. The others were idled because of a drop in demand. The company explained that few people are allowed in to the plant because the machinery and processes it uses are proprietary.
The company showed the governors and reporters how the product is made.
First, a conveyer belt brought in scraps left over from a plant next door that produces steaks, roasts and other cuts of meat. The scraps were heated to around 100 degrees Fahrenheit to facilitate separation of the fat, then dumped into a huge meat grinder to pull out fat, cartilage, bone and connective tissue.
A centrifuge spinning 3,000 times a minute continued the separation process. Inside a third machine the material was treated with ammonia hydroxide gas to eliminate bacteria.
The treated bits of meat were moved into large roller-presses inside drums up to 14 feet tall, which flattened the meat and froze it down to 15 degrees, which lightened its color. The meat was pried out of the drums, then put in a grinder that churned out 60-pound bricks that were packaged individually for shipment.
Companies selling hamburger fold the filler from the bricks into the hamburger to make it leaner.
At a news conference held at a nearby hotel, Brownback said the activists' campaign used a "catchy name" to discourage people from eating healthier beef.
"We're trying to get people to eat better and now what is going to happen because of this unmerited, unwarranted food scare, and that's what it is ... you're going to drive up the price of lean ground beef," Brownback said.
Meat producers have predicted hamburger prices will rise as the spring grilling season begins because they will no longer be able to use the cheap filler to mix with the higher quality cuts of beef.
Beef Products has idled three plants with 650 workers while it tries to restore demand for the product and Cargill also said it had scaled back production.