The main objective of this study was to evaluate the effects of salt and oil on volatile fatty acid (VFA) generation during anaerobic digestion. Lab-scale sequencing batch reactor experiments were operated at various salt concentrations of 3 g/L (S3), 6 g/L (S6), 9 g/L (S9), 12 g/L (S12) and oil concentrations of 5 g/L (O5), 15 (O15), 25 g/L (O25), 35 g/L (O35) under previously determined optimal conditions (35 degrees C and pH of 6). The results revealed that VFA generation was reduced 18.7% and 89.9% at S6 and S12. Similarly, VFA generation decreased by 6% and 67.2% at O5 and O35, respectively. The salt concentration < 6 g/L or the oil concentration < 5 minimally inhibited the VFA yield. Moreover, the VFA yield remain stable and the lag phase was shorten at salt and oil concentration at 6 and 5 g/L, respectively (S6O5) compared with a single addition. The above finding indicates the possibility of VFA generation under conditions where salt and oil coexist. Thus, a salt concentration < 6 g/L and/or oil concentration < 5 g/L in food waste was suitable for VFA generation in food waste fermentation. (C) 2017 Elsevier Ltd. All rights reserved.