You know how we got taught in elementary school that Native Americans used every part of the Buffalo? Well early 20th century industrial food processors were good at that too.

From Upton Sinclair’s The Jungle

 “No tiniest particle of organic matter was wasted in Durham’s. Out of the horns of the cattle they made combs, buttons, hairpins, and imitation ivory; out of the shinbones and other big bones they cut knife and toothbrush handles, and mouthpieces for pipes; out of the hoofs they cut hairpins and buttons, before they made the rest into glue. From such things as feet, knuckles, hide clippings, and sinews came such strange and unlikely products as gelatin, isinglass, and phosphorus, bone black, shoe blacking, and bone oil. They had curled-hair works for the cattle tails, and a “wool pullery” for the sheepskins; they made pepsin from the stomachs of the pigs, and albumen from the blood, and violin strings from the ill-smelling entrails. When there was nothing else to be done with a thing, they first put it into a tank and got out of it all the tallow and grease, and then they made it into fertilizer.”

I wonder if the modern food industry is like this? If so, given the rage for environmentalism,  they should publicize that.