E. coli is found in the intestines and feces of both animal and humans. One particularly virulent strain, , is found specifically in the lumen of cattle raised in CAFOs. Because cattle are fed corn in CAFOs instead of grass, this changes the pH of the lumen so that it is more hospitable to "E". "coli". Grain-fed cattle have 80 percent more of this strain of "E". "coli" than grass-fed cattle. However, the amount of "E". "coli" found in the lumen of grain fed cattle can be significantly reduced by switching an animal to grass only a few days prior to slaughter. This reduction would decrease the pathogen's presence in both meat and waste of the cattle, and decrease the "E". "coli" population found in anaerobic lagoons.