Charles Thom

Charles Thom (November 11, 1872 – May 24, 1956) was an American microbiologist and mycologist. Born and raised in Illinois, he received his PhD from the University of Missouri, the first such degree awarded by that institution. He studied the microbiology of dairy products and soil fungi, and in particular researched the genera Aspergillus and Penicillium. His work influenced the establishment of standards for food handling and processing in the USA. He pioneered the use of culture media to grow microorganisms, and, with food chemist James N. Currie, developed a process to mass-produce citric acid using Aspergillus. Thom played an important role in the development of penicillin in World War II.

Early life Thom was born in Minonk, Illinois in 1872, the fifth of six boys. His parents were Angus Sutherland Thom and Louisa (Herick) Thom, Scottish/Irish farmers who had settled in Illinois shortly before the American Civil War. Charles Thom was raised in a strongly religious household; his father was an elder in the Presbyterian church. Thom upheld Presbyterian values throughout his life, kept active in church affairs, and became a staunch prohibitionist. His early years spent working on his father's farm instilled the value of a strong work ethic, and first-hand knowledge of agricultural practices that would prove useful in his later career.