A process for processing fresh brewer's spent grains (BSG), the process comprising the steps of: • Producing a mash comprising barley malt; • Separating the mash from BSG; • Collecting the BSG; • Microbiologically stabilizing the collected BSG to obtain a MS-BSG slurry by acidifying the BSG to a pH of 4 or lower, such that the BSG: is acidified prior to reaching mycotoxin levels higher than 3μg/kg Ochratoxin A (OTA), higher than 750 μg/kg deoxynivalenol (DON), higher than 20 μg/kg nivalenol (NIV), and higherthan 75 μg/kg zearalenone (ZEA); and/or, has a colony count of not higher than 10 3 CFU/g MS-BSG total aerobic bacteria; not higher than 10 3 CFU/g MS-BSG fungi; not higher than 10 3 CFU/g MS-BSG yeast; not higher than 10 3 CFU/g MS-BSG mesophilic aerobic bacteria; and not higher than 10 3 CFU/g MS-BSG total anaerobic bacteria, after one week of storage at 25°C; wherein said MS-BSG slurry is separated into a water soluble and water insoluble fraction by filtration or decanting to obtain said water soluble fraction as a liquid phase (permeate) comprising salts, oligosaccharides, water soluble proteinaceous material and water soluble arabinoxylans; and said water insoluble fraction as a wet solid phase comprising precipitated proteins and water-insoluble arabinoxylans; • drying said fractions; and • powdering said fractions to a powder, wherein said powder has an average mean particle size of below 1.4 mm. • Producing a mash comprising barley malt; • Separating the mash from BSG; • Collecting the BSG; • Microbiologically stabilizing the collected BSG to obtain a MS-BSG slurry by acidifying the BSG to a pH of 4 or lower, such that the BSG: is acidified prior to reaching mycotoxin levels higher than 3μg/kg Ochratoxin A (OTA), higher than 750 μg/kg deoxynivalenol (DON), higher than 20 μg/kg nivalenol (NIV), and higherthan 75 μg/kg zearalenone (ZEA); and/or, has a colony count of not higher than 10 3 CFU/g MS-BSG total aerobic bacteria; not higher than 10 3 CFU/g MS-BSG fungi; not higher than 10 3 CFU/g MS-BSG yeast; not higher than 10 3 CFU/g MS-BSG mesophilic aerobic bacteria; and not higher than 10 3 CFU/g MS-BSG total anaerobic bacteria, after one week of storage at 25°C; wherein said MS-BSG slurry is separated into a water soluble and water insoluble fraction by filtration or decanting to obtain said water soluble fraction as a liquid phase (permeate) comprising salts, oligosaccharides, water soluble proteinaceous material and water soluble arabinoxylans; and said water insoluble fraction as a wet solid phase comprising precipitated proteins and water-insoluble arabinoxylans; is acidified prior to reaching mycotoxin levels higher than 3μg/kg Ochratoxin A (OTA), higher than 750 μg/kg deoxynivalenol (DON), higher than 20 μg/kg nivalenol (NIV), and higherthan 75 μg/kg zearalenone (ZEA); and/or, has a colony count of not higher than 10 3 CFU/g MS-BSG total aerobic bacteria; not higher than 10 3 CFU/g MS-BSG fungi; not higher than 10 3 CFU/g MS-BSG yeast; not higher than 10 3 CFU/g MS-BSG mesophilic aerobic bacteria; and not higher than 10 3 CFU/g MS-BSG total anaerobic bacteria, after one week of storage at 25°C; wherein said MS-BSG slurry is separated into a water soluble and water insoluble fraction by filtration or decanting to obtain said water soluble fraction as a liquid phase (permeate) comprising salts, oligosaccharides, water soluble proteinaceous material and water soluble arabinoxylans; and said water insoluble fraction as a wet solid phase comprising precipitated proteins and water-insoluble arabinoxylans; • drying said fractions; and • powdering said fractions to a powder, wherein said powder has an average mean particle size of below 1.4 mm. <EOS>