The role has been created as part of a restructure aimed at consolidating sales, marketing and technical activities for the major supermarkets.
The three companies within the division are British Bakeries; Rank Hovis and Le Pain Croustillant, which supplies frozen part-baked breads.
Moss takes up the role on August 1. She will have responsibility for marketing and innovation for brands such as Hovis, Mothers Pride, Nimble and Granary. Moss was brand manager on Hovis at the time of its relaunch in 2001, which saw the packs wrapped with images of food such as eggs and baked beans.
Moss also takes control of the Enjoy Organic brand, whose bakery products were integrated into British Bakeries earlier this year.
RHM, part of venture capitalist Doughty Hanson, is thought to be streamlining ahead of its flotation.