The effect of oxidation-reduction potential (Eh) on the outgrowth, toxin production, and chemical inhibition of Clostridium botulinum type A spores was investigated. Growth, toxin formation, and Eh7 changes were monitored in an airtight four necked flask containing electrodes for continuous measurement of Eh and pH and connections for the exchange and mixing of prepurified nitrogen and anaerobic carbon dioxide. Strict anaerobic procedures and prepurified media were utilized to facilitate controlled conditions. In the electrode vessel the media were poised at the different Eh levels by sparging the pre reduced media with oxygen free nitrogen or by sparging oxidized media (media autoclaved under air) with the nitrogen gas. Outgrowth, toxin production, and Eh7 changes were measured under various growth conditions. In both oxidized (Eh7 = -60mv) and reduced (Eh7 = -145mv) media, there were no significant differences observed in the growth and toxin formation under uninhibited growth conditions. However, growth and toxin production were further delayed and/or decreased in the oxidized media as compared to the reduced media during inhibition by sodium chloride (5.5% and 6.5%), hydrogen ions (pH 5.2 and 5.3), and sucrose (30%). / Master of Science