To estimate the corrosion damage of the SS304 samples specifically caused by the bacteria in the biofilm, the disc samples were removed after exposure to S1, S2 and S2 media and were cleaned by immersing in 1 M HNO3 solution for 15 minutes at 60 ℃. After the removal of biofilm, the surface morphology of the SS304 samples was examined in the scanning electron microscope (SEM: JEOL JSM-5600). The chemical composition of the SS304 surface after biofilm removal was determined by using Fourier Transform Infrared (FTIR) spectroscopy (Bio-Rad FTS-3500 ARX), operated in the infrared-reflectance mode. The FTIR spectra were obtained within 400 -4,000 cm -1 wavenumbers with 8 cm -1 resolution at a scan rate of 64 scans per spectrum.