The Food and Drug Administration conferred with public health officials from 50 states on Wednesday about how best to strengthen rules governing compounding pharmacies in the wake of a national meningitis outbreak caused by a tainted pain medication produced by a Massachusetts pharmacy. It was the first public discussion of what should be done about the practice of compounding, or tailor-making medicine for individual patients, since the F.D.A. commissioner, Dr. Margaret Hamburg, testified in Congress last month about the need for greater federal oversight of large compounding pharmacies.