562) and E. coli (DMST 4212) (DMST
stands for Department of Medical Sciences Culture Collection, Thailand)
were used in this study. The water samples were prepared by diluting S. aureus and E. coli of 108 CFU/mL in sterile deionized water (autoclave:
TOMY, SX-700, Japan) to obtain initial S. aureus and E. coli concentrations from 104 to 107 CFU/mL.
colony-forming unit, which is widely used to estimate the number of
visible microorganisms in test samples.91 (link)