Abstract: A method for upgrading human food and animal feed, rendering harmless the contaminating mycotoxins, increasing protein and nucleotide content, providing immuno-modulation, enhancing flavor and palatability is proposed. The method comprises a food functional additive/supplement and feed additive based on yeast biomass processed to enhance the bioavailability and biological activity of its components using dry micron milling with optional agglomeration. The resulting product contains all biologically active components originally present in intact live yeast. Compared to existing practice, the new process is much faster, cheaper, less hardware demanding, less prone to microbial contamination, provides intact biopolymers and results in insoluble product fraction with high surface area.