World of Chemistry on Mary Engle Pennington

Mary Engle Pennington was a bacteriological chemist who revolutionized methods of storing and transporting perishable foods . Denied a B.S. degree in 1895 because she was a woman, Pennington went on to head the U.S. Department of Agriculture's food research lab. As persuasive as she was resourceful, Pennington was able to convince farmers, manufacturers, and vendors to adopt her techniques. She developed methods of slaughtering poultry that kept them fresh longer, discovered ways to keep milk products from spoiling, and determined how best to freeze fruits and vegetables. Pennington was the first female member of the American Society of Refrigerating Engineers. She eventually went into business for herself as a consultant and investigator in the area of perishable foods.

Pennington was born October 8, 1872, in Nashville, Tennessee. She was the first of two daughters born to Henry and Sarah B. Molony Pennington. Pennington spent most of her early life in Philadelphia, where her family moved to be closer to their Quaker relatives. With her father, a successful label manufacturer, she shared a love of gardening.

Pennington found her way to the field of chemistry through a library book on that subject. Her interest prompted her to enter the Towne Scientific School of the University of Pennsylvania, an uncommon occurrence for a woman at that time. In 1895 she received a certificate of proficiency, having been denied a B.S. because of her gender. Not to be deterred, Pennington continued academic work, earning her Ph.D. at age twenty-two from the University of Pennsylvania with a major in chemistry and minors in zoology and botany. This degree was conferred under an old statute that made exceptions for female students in "extraordinary cases." Pennington then accepted a two-year fellowship at the university in chemical botany, followed by a one-year fellowship in physical chemistry at Yale.

From 1898 to 1906 Pennington served as instructor in physiological chemistry at Women's Medical College. During this same period, she started and operated a clinical laboratory performing analyses for physicians, and was a consultant to Philadelphia regarding the storage of perishable foods during the marketing process. Her reputation for quality work led to an appointment as head of the Philadelphia Department of Health and Charities Bacteriological Laboratory. One of her first goals here was the improvement of the quality of milk and milk products. Her natural gift of persuasion aided her in convincing ice-cream manufacturers and vendors to adopt simple steps to help avoid bacterial contamination of their foods.

The Pure Food and Drug Act was passed in 1906, and the U.S. Department of Agriculture planned to establish a research laboratory to help provide scientific information for prosecutions under the act. Specifically, this lab would be concerned with the quality of eggs, dressed poultry, and fish. With the encouragement of Harvey W. Wiley, chief of the chemistry section of the USDA and a longtime family friend, Pennington took and passed the civil service exam in 1907 under the name M. E. Pennington. Unaware that Pennington was a woman, the government gave her a post as bacteriological chemist. Wiley promoted her to head the food research lab in 1908. That same year she delivered an address for Wiley to a startled all-male audience at the First International Congress of Refrigeration.

During Pennington's tenure the laboratory effected alterations in the warehousing of food, its packaging, and use of refrigeration in transport. Pennington eventually developed techniques that were commonly used for the slaughter of poultry, ensuring safe transport and high quality long after the butchering occurred. In the area of eggs, a highly perishable item especially in warm weather, she again used her powers of persuasion. She worked to convince farmers to collect and transport eggs more frequently during warmer weather. She is also credited with developing the egg cartons that prevent excessive breakage during transport.

During World War I, Pennington consulted with the War Shipping Administration. The United States had forty thousand refrigerated cars available for food transport at the start of the war. Pennington determined only three thousand of these were truly fit for use, with proper air circulation. Following the war she was recognized for her efforts with a Notable Service Award given by Herbert Hoover.

Pennington made another career change in 1919 when she accepted a position as manager of research and development for New York's American Balsa Company, a manufacturer of insulating material. In 1922 she made her final career move, starting her own business in New York as a consultant and investigator in the area of perishable foods . She was particularly interested in frozen foods, helping to determine the best strains of fruits and vegetables for freezing, and the best method for freezing them.

Pennington was the author of books, articles, pamphlets, and several government bulletins. She gave many addresses and was the recipient of several awards, including the American Chemical Society's 1940 Garvan Medal to honor a woman chemist of distinction. Pennington, in fact, was one of the first dozen female members of the society. She was the first female member of the American Society of Refrigerating Engineers, and the first woman elected to the Poultry Historical Society's Hall of Fame. She served as director of the Household Refrigeration Bureau of the National Association of Ice Industries from 1923 to 1931.

Pennington earned herself the reputation for always producing quality work. She was accepted in industry even while she was working for the government in enforcing the Pure Food and Drug Act. She maintained her interest in gardening and botany, growing flowers in her apartment. She was a lifelong member of the Quaker Society of Friends. Pennington, who never married, was still working as a consultant and as vice president of the American Institute of Refrigeration when she died on December 27, 1952, in New York City.