Mary Engle Pennington
Born in 1803, John Gorrie, was granted the first U.S. patent for mechanical refrigeration in 1851. Mary Engle Pennington, also born this month in 1872, spent her career studying refrigeration and how best to use it for food preservation.
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When people called Mary Engle Pennington (1872–1952) “The Ice Lady” it was not because of her personality. Pennington, a bacteriological chemist, spent most of her career studying refrigeration and how best to use it to keep foods fresh and safe to eat. She designed refrigerators for the home and refrigerated cars for railroads, and she set scientific standards for food safety.
In 1904 Pennington took a job with the City of Philadelphia, where she was in charge of ensuring the safety of milk and dairy products sold in the city. Her work was now more bacteriology than chemistry, and this would be true for most of her career. Contaminated food was a big problem in those days, largely due to unsanitary handling. Pennington knew that legal regulations were necessary, but she also knew she’d meet resistance if she tried to force the issue. Instead, she met one-on-one with farmers and vendors to explain the problem, actually showing ice cream vendors slides of the bacteria that were found growing in their buckets. She convinced farmers of the need to inspect their milk before shipping it, and vendors of the need to boil their buckets. When she finally pushed for laws requiring such practices, she met little opposition. The Ice Lady would become famous for this warm and personal approach.
Pennington soon caught the eye of the public health crusader Harvey Washington Wiley, who recruited her to work for him at the U.S. Department of Agriculture (USDA). At the USDA, she did pioneering research on refrigeration and how it could be used to keep food safe from bacteria, which can spoil food.
Visit Chemistry in History to learn more about Mary Engle Pennington.
Excerpted with permission, Chemical Heritage Foundation
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