Relocating to Washington, D.C., Benjamin R. Jacobs joined the federal agency, the Bureau of Chemistry (now the Food and Drug Administration, ) of the United States Department of Agriculture, with which he had a long association. Some of his work was under the auspices of in the Food Control Laboratory of the department. His first experiments and publication dealt with the adulteration of flour and the enforcement of stricter controls on industry under the 1906 Pure Food and Drug Act. He also worked with one of the first women chemists in the department, Hannah L. Wessling.