At the beginning of the twentieth century, life expectancy was 49 years. It had increased to about 60 years by the 1930s and to more than 70 years by the 1960s. In 1990, life expectancy reached about 75 years (DHHS/PHS/CDC/NCHS, 1991). These changes were due in part to improvements in sanitation, control of infectious disease, and knowledge of nutrition (Meredith, 1932). It became more widely recognized that the food Americans were eating had an important effect on their health. One result of this awareness was that the Federal government took over control of the safety of the food supply by preventing the interstate transportation of unfit food. The States, for their part, continued to be responsible for food within their respective borders. During Congressional action on the legislation that subsequently became the 1906 Pure Food and Drugs Act, a witness representing a large food distributing company, who appeared before the House Committee on Interstate and Foreign Commerce to oppose passage of the pending food bill, declared that the food industry of the country rested on fraud and deception. "Make us leave preservatives and coloring matter out of our food," he declared, "and call our products by the right name and you will bankrupt every food industry in the country" (Wiley, 1914). Wiley suggested that manufacturers and dealers who would otherwise have made pure and properly branded goods were forced by unfair competition to practice the arts of adulteration and misbranding.

During the same period, work of U.S. Public Health Service scientists an the dietary cause of pellagra—a disease resulting from a deficiency of niacin—brought into sharp focus the public health importance of good nutrition and added a new responsibility to the mission of public health officials, which earlier had been limited to sanitation and adulteration. The first 40 years of this century constituted the era of discovery of the nutrition deficiency diseases and isolation of the responsible nutrients (Erdman, 1989).

A book published prior to the enactment of FDCA evaluated public health problems in terms of the debit and credit sides of the scientific ledger. It suggested that the problems that still remained on the debit side were polio, encephalitis, influenza, and cancer. On the credit side, it listed smallpox vaccination; antitoxin, toxin-antitoxin, and one-dose toxoid for diphtheria; typhoid and yellow fever vaccines; antilockjaw serum; vitamins for scurvy, rickets, and pellagra; and sanitary knowledge to keep foods and water supplies germ free (Davis, 1934). The author reported on a series of cases of "disease of bad plumbing" that occurred in Chicago in the early 1930s in which food handlers were contaminating food as a result of the use of contaminated water.