FIELD: agriculture. SUBSTANCE: method involves cleaning grain from contaminants before laying for storage; treating grain with aerosol flow of propionic acid comprising chitosan additive, said flow being preliminarily directed through supersonic horn; using chitosan source such as preparation produced by sequential extracting of Mortierella verticullata micromycet biomass by predetermined process. EFFECT: increased efficiency in eliminating of surface microflora from grain and reliable grain storage.
