Methods of washing a grain particle material and/or a stillage composition, and related systems and biorefineries

A method comprising:

• grinding corn to produce corn flour;
• combining the corn flour with water to form a first slurry;
• separating the first slurry into a solids fraction and at least one liquid fraction;
• treating the at least one liquid fraction to reduce a concentration of one or more mycotoxins in the at least one liquid fraction;
• after the treating, recycling at least a portion of the at least one liquid fraction to form the first slurry;
• combining the solids fraction with water to form a second slurry;
• hydrolyzing at least a portion of corn starch in the second slurry into one or more monosaccharides to form a fermentable composition;
• fermenting the fermentable composition to form a fermented composition comprising ethanol;
• and
• forming an animal feed product from at least a portion of the fermented composition.