I keep reading articles that make it sound like the process to create so-called "pink slime" was invented in the 1990s. The process dates back to at least 1960, as evidenced by the patent filed by Chicago meatpacker Armour and Company on April 5, 1960 and approved in 1962. Patent 3,062,655 was initially intended to create a "water insoluble defibrillated meat protein" that could be added to cakes and candies. This was before the product was added to ground beef, as it is today.
I've embedded the patent below and you can read about my take on pink slime at The Daily.