Journal of Bioscience and Bioengineering VOL. 110 No. 3, 308 – 313In the current study, the effectiveness of slightly acidic electrolyzed water (SAEW) on an in vitro inactivation of Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Salmonella spp. was evaluated and compared with other sanitizers. SAEW (pH 5.6, 23 mg/l available chlorine concentration; ACC; and 940 mV oxidation reduction potential; ORP) was generated by electrolysis of dilute solution of HCl (2%) in a chamber of a non-membrane electrolytic cell. One milliliter of bacteria suspension (ca. 10–11 log 10 CFU/ml) was mixed with 9 ml of SAEW, strong acidic electrolyzed water (StAEW; ca. 50 mg/l ACC), sodium hypochlorite solution (NaOCl; ca.120 mg/l ACC) and distilled water (DW) as control and treated for 60 s. SAEW effectively reduced the population of E. coli, S. aureus and Salmonella spp. by 5.1, 4.8, and 5.2 log 10 CFU/ml. Although, ACC of SAEW was more than 5 times lower than that of NaOCl solution, they showed no significant bactericidal difference (p N 0.05). However, the bactericidal effect of StAEW was significantly higher (p b 0.05) than SAEW and NaOCl solution in all cases. When tested with each individual test solution, E. coli, S. aureus and Salmonella spp. reductions were not significantly different (p N 0.05). These findings indicate that SAEW with low available chlorine concentration can equally inactivate E. coli, S. aureus and Salmonella spp. as NaOCl solution and therefore SAEW shows a high potential of application in agriculture and food industry as an environmentally friendly disinfection agent.