Abstract Coiled tube UV reactors were used to investigate the influence of tube diameter (1.6mm ID, and 3.2mm ID) and Reynolds number (Re) to inactivate Escherichia coli W1485 and Bacillus cereus spores in raw soymilk (RSM). Four levels of Re (343, 686, 1029 and 1372) were tested in RSM inoculated separately with each bacterium and treated in the UV reactors at a constant residence time of 11.3s with UV-C dose of 11.187mJ/cm2 at 253.7nm. Inactivation efficiency of both microorganisms increased with Re. Maximum reductions of 5.6log10CFU/ml of E. coli and 3.29log10CFU/ml of B. cereus spores were achieved in the 1.6mm ID UV reactor. Inactivation efficiency was higher in the 1.6mm ID UV reactor than the 3.2mm ID UV reactor for both the organisms. Effect of UV-C light on lipid oxidation of untreated RSM, measured as malondialdehyde and other reactive substances (MORS) content, was much higher (95nmol/ml) than the UV-treated (58nmol/ml) and thermally pasteurized (55nmol/ml) RSM during the storage period of 7 days. The UV-C treatment can be effectively used for reducing E. coli cells and B. cereus spores in soymilk without compromising its quality.