Effects of Sorbate and Propionate on Growth and Aflatoxin Production of Sublethally injured Aspergillus parasiticus

Abstract

Growth and aflatoxin production by injured spores (heat, 55°C for 15 min, γ-irradiation, 50 Krad) of Aspergillus parasiticus in the presence of sorbate (0.05 and 0.1%) and propionate (0.2 and 0.4%) were studied in YES broth at pH 4.5, 5.5 and 6.5, and 25°C for 21 days. Aflatoxin production was accelerated in the early stages of growth by γ-irradiation, but not heat. Growth and aflatoxin were delayed in cultures from low numbers of uninjured spores. Aflatoxin increased and was produced sooner by low numbers of uninjured spores in 0.05% sorbate. Both inhibitors slowed growth of injured spores more than non-injured. Inhibition of aflatoxin was dependent on the concentration of inhibitor, pH and injury.