On July 13, 1935, her 34th birthday, Tillie Lewis opened the first Flotill cannery for tomato products in Stockton, California. Operating the first cannery owned by a woman, by 1940 she had made San Joaquin County the top tomato-producing county in the United States.

In addition to tomatoes, Lewis's Flotill Products, Inc., canned other fruits and vegetables, baby food, and frozen juices; during the Second World War, the company also became the largest producer of C-rations for the U.S. Army. By 1951, Flotill Products, later known as Tillie Lewis Foods, Inc., was earning $30 million per year, making it one of the five largest canning companies in the country. In the same year, Lewis was named "businesswoman of the year" by the Associated Press.

See also: "Tillie Lewis opens cannery for American-grown Italian tomatoes" in This Week in History.