Breads are also among some of the oldest fermented foods and approx. 60% of the world population eats flat breads and gruels made from grains (Beuchat, 1997). Sourdough breads are made with starters containing yeasts such as Saccharomyces spp. and Torulopsis and homofermentative and heterofermentative lactic acid bacteria. Heterofermentative strains such as Lb. sanfrancisco, Lb. brevis and Lb. fermentum are responsible for the characteristic sensory qualities of such breads.