A recent study by the Centers for Disease Control found that a single fast-food hamburger contained beef from more than 100 cows. In the last few decades, American meat production has become a highly mechanized and centralized industry, bringing about significant changes not only in the way meat is produced but also in the way Americans eat. These changes have forced the U.S. Department of Agriculture to institute a new meat inspection process, which gives far greater control to the powerful meat industry. This spring, FRONTLINE investigates the modern meat industry and the safety of our current meat supply.