Microbiology of salt rising bread

Salt rising bread (SRB) is an Appalachian traditional bread made without yeast, using a starter derived from flour, milk and potatoes. The "rising agent" has been identified as Clostridium perfringens, not salt, and is presumably derived from the environment. Although no cases of illness have been attributed to SRB, C. perfringens type A is a common cause of food poisoning from meats and gravies. Other C. perfringens isolates may cause enteritis necroticans (pig-bel disease) and gas gangrene. Past research documents that pathogenic strains derived from wounds may be used to produce bread and that bacteria isolated from this bread retain their pathogenicity. SRB starter samples were cultured at the University of Pittsburgh and abundant C. perfringens, type A grew out of all samples. However none of the cultures were positive for enterotoxin and thus would be unlikely to cause human food borne disease. While this does not preclude the possibility of other starter mixes containing enteropathogenic strains, the baking process appears to reduce bacterial contamination to safe levels and SRB has not been implicated in causing any human disease.