Thressa entered Cornell University on a New York State Regents Scholarship and supported herself by working as a waitress for four hours a day. She graduated in 1940 with a B.S. in microbiology. Thressa then worked as a bacteriologist in a company that produced paper containers for milk, but she did not find this industrial job very stimulating. After some months, Thressa moved to the New York State Agricultural Station in Geneva, where she conducted research on the vitamin requirements of lactic acid bacteria and she also took courses at Cornell. In two years Thressa received an M.S. in bacteriology and nutrition from Cornell. She decided to continue her education at the University of California, Berkeley.
