Spore-forming bacteria associated with bread production: spoilage and toxigenic potential

Contamination of bread ingredients with Bacillus spp. spores and their persistence in bread is source of concern mainly for its industrial production. The microbial eco-system of raw materials used for bread-making and in particular spore-forming bacteria play a role in the development of "bread rope spoilage". Heat resistant spores can survive the baking process and under warm and humid favorable conditions spore germination occurs and vegetative cells cause the rope spoilage, a deterioration process of bread texture. The chapter analyzes the factors contributing to the rope occurrence such as the complexity of the microbiota of sporeformers contaminating the raw materials, the physiological and genetic traits of the Bacillus strains belonging to several species responsible for the alteration including potential toxigenic species and the spore's heat resistance. The chapter also examines some strategies to prevent and/or control the rope spoilage, with particular regard to the application of predictive microbiology to evaluate the contamination risk and to the use of microbial biotechnologies as tools for controlling microbial growth to counteract the alterative phenomenon.