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.