WASHINGTON — Kathleen A. Merrigan, deputy secretary at the U.S. Department of Agriculture, will address a range of pressing industry issues at a joint baking industry meeting in Washington. Dr. Merrigan will discuss food safety, commodity volatility, nutrition and the rising rate of obesity incidence at a Sept. 15 meeting of the boards of the American Bakers Association and the Allied Trades of the Baking Industry. Dr. Merrigan assumed her role earlier this year after Senate confirmation. She has been an assistant professor and director of the Agriculture, Food and Environment Program at Tufts University in Boston. Dr. Merrigan’s wide-ranging career included an earlier stint at the U.S.D.A. when she was administrator of the Agricultural Marketing Service from 1999-2001. Robb MacKie, A.B.A. president and chief executive officer, said the boards, as part of ongoing dialogue with government officials, will stress the need to build upon the current food safety infrastructure and will emphasize the valuable role of enriched and whole grains in a healthy diet.