Improving microbial quality of wheat flour using ethanol-water mixture as a tempering solution

Wheat flour may contain high microbial load due to the contamination of the wheat surface by different sources. This situation leads to outbreaks of foodborne diseases caused by wheat and wheat-based products. In this research, a novel application has been developed to reduce microbial contamination at the tempering stage of wheat. The effect of water with different concentrations of ethanol (10–90% (v/v)) against the microbial load of wheat was evaluated. Although 70% ethanol is widely used as an antimicrobial agent, the significant reduction in aerobic plate count (APC) and yeast-mold count (YMC) in wheat was 5.02 ± 0.20 log CFU/g and 5.96 ± 0.22 after tempering with 50% ethanol and above, respectively. The mechanism for the antimicrobial effect of 50% ethanol is that wheat absorbs water faster than ethanol, causing a rise in ethanol concentration on the grain surface over time. The chemical and technological properties of wheat flour were also investigated at 50% ethanol concentration, which showed the highest microbial reduction. This study shows adding ethanol at the tempering stage reduces the microbial load of wheat while maintaining some functional quality of the flour without requiring any treatments or time.