Corn has been subjected to various genetic modifications that have resulted in a crop that is resistant to pesticides, a
feature that has increased the productivity of corn for farmers. Corn is not only food for humans, but is also feed for farm animals as diverse as cattle, pigs, and poultry that are the major sources of meats for the US diet. Corn is the primary source of high fructose corn syrup (HFCS) in the US. Marshall and Kooi (1957) developed the process for making HFCS.