In 1991 a group of three investigators from representative states in the US Middle West measured short chain fatty acid production from the digestion of fivers by human intestinal bacteria. Three healthy male donors served as the sources of the inoculum for the anaerobic fermentation of agriculture wastes as well as food grade undigestible polysaccharides. The media included salts, yeast extract, vitamins, and the reducing agent/sulfur containing amino acid cysteine.