The present account focuses on upscaling of biohydrogen (H-2) production at semi-pilot scale bioreactor using composite food waste. Experiments were conducted at different organic load (6, 12, 18, 30, 40, 50 and 66 g COD/l) conditions. H-2 production increased with an increasing organic load up to 50 g COD/l (9.67 l/h) followed by 40 g COD/1 (6.48 1/h), 30 g COD/1 (1.97 l/h), 18 g COD/1 (0.90 l/h), 12 g COD/1 (0.78 l/h) and 6 g COD/1 (0.32 l/h). H-2 production was affected by acidification (pH drop to 3.96) at 66 g COD/1 operation due to the excess accumulation of soluble metabolites (5696 mg VFA/1). Variation in organic load of food waste influenced the overall hydrogen production efficiency. (C) Copyright 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.