Take a cow. Chop it into pieces. Sell the edible bits to supermarkets, ship its hide to a handbag factory, send leftover bones and organs to a rendering plant. Now, what is left? In most of the developed world, the answer is simple: pet food. The sinew, gristle and fat regarded as unfit for human consumption are taken away by a pet food maker and turned into something the salmonella-resistant stomach of your average Labrador will find vaguely digestible.
But in the United States, they do food differently. Here, in the land of GM corn, 26 per cent obesity and a Government which classifies pizza as a "vegetable", scientists have discovered a way to turn bacteria-ridden scraps from the abattoir floor into a substance called "pink slime", which is then sold to unwitting consumers of hamburgers, tacos and other beef-based junk products.
The process involves sticking bovine off-cuts in a heated centrifuge, so they separate into a mixture of liquid fat and a putty-coloured paste.
That substance is then treated with ammonium hydroxide (a chemical used in household cleaners and home-made bombs) to kill off salmonella and E. coli. Then it's mixed with regular beef and - hey presto! - you have "all natural" mince.
In 2001, it became legal to sell "pink slime" in the US. Today, more than half the ground beef sold there contains the stuff. The US Department of Agriculture, which supposedly regulates the food industry, does not require it to be mentioned on ingredient lists. Since its provenance is a cow, they insist, you can call it "beef". If you think that's a bit rum, you're not alone. For years, US foodies have earnestly cited "pink slime" as exhibit A in the list of liberties taken by a rapacious food industry. Not for nothing, they argue, has the stuff been banned in Europe, where mechanically separated meat from cows and sheep has been prohibited since the era of BSE.
It took an Englishman, however, to turn their complaints into national outrage. A year ago, Jamie Oliver jollified the US version of his Food Revolution TV show by using a cow called Scarlet and a tumble dryer to demonstrate how something he calls "crap" became a staple of the US diet. Video of his stunt was uploaded to YouTube, and shared via social media. Opposition to "pink slime" slowly built.
In January, McDonald's announced the removal of "pink slime" from its burgers. So did Burger King and Taco Bell. This month, as the product became a burgeoning national talking point, several major supermarkets went slime-free. School districts were allowed to start banning it and dozens swiftly did. Yesterday, Beef Products, pink slime's leading manufacturer, shut down three of its four plants, citing swiftly falling demand. According to the American Meat Institute, 600 jobs could now be lost.
"It's a sad day for the families," claimed a spokesman. Though not, one must presume, for their diets.