Effect of sublethal concentrations of propionic or butyric acid on growth and aflatoxin production by Aspergillus flavus

Propionic or butyric acid was added at sublethal doses (0.1–2 mg/ml) to a growth medium supporting growth of Aspergillus flavus and subsequent aflatoxin production. A reduction in growth and aflatoxin production occurred when the acids were added at the time of inoculation. Addition of the acids to cultures at different times resulted in little effect on growth but production of aflatoxin after 12 days was reduced with earlier time of application for both propionic and butyric acid. When the acids were added to rough rice with a moisture content of 21% and inoculated with A. flavus fungal growth and aflatoxin production were reduced relative to non-inoculated controls. Early application of acids resulted in lower yields of aflatoxin.