BOSTON – The first days of the spring public relations campaign of the Grain Foods Foundation generated nearly 100 million impressions, according to early analysis by Mullen, the G.F.F. agency. The campaign launched April 10 with a satellite media tour featuring spokesperson Mia Hamm, a retired woman’s soccer star. Ms. Hamm participated in 21 interviews including sessions with Shape magazine’s online editor and live national radio broadcasts with USA Radio Network’s Daybreak USA program, Health Radio Network and the Valder Beebe Show. Ms. Hamm also filmed video responses to nutrition and fitness questions submitted by G.F.F. Facebook fans. “This week alone, we secured nearly 100 million impressions including placements from the satellite media tour as well as press release pickup from Perishable News, The Denver Post and The Sacramento Bee,” said Jennifer Geiger, an account supervisor at Mullen. Additional interviews have been lined up for April, she said.