Control of Aspergillus and Fusarium In Vitro and in Wheat Using Sodium Bisulfate Acidulant

We evaluated the efficacy of an acidulant, sodium bisulfate (SBS) against Aspergillus flavus and Fusarium graminearum in a simulated wheat storage model. The broth microdilution method was used to determine the MIC of SBS against the molds. Sterile wheat samples were inoculated with mold culture, followed by a 30-min attachment and the application of SBS treatment (0, 0.5, 1.0, and 1.5%, w/v). Positive and negative controls were maintained. The final moisture in wheat was consistent with the tempering process (16%). The treatments were incubated at 25°C, and microbiological analyses were performed at predetermined times (0, 6, 12, 18, 24, and 48 h). The MIC of SBS against A. flavus and F. graminearum was 0.31 and 0.16%, respectively. In wheat, the highest concentration of SBS used (1.5%) reduced (P ≤ 0.05) ~1.0 and 1.3 log of A. flavus after 18 and 48 h, respectively, whereas all three concentrations of SBS lowered (P ≤ 0.05) F. graminearum to a nondetectable level within 18 h. Overall, the addition of SBS in tempering water during the wheat tempering process seemed effective in controlling F. graminearum and partly effective against A. flavus.