Romaine lettuce leaves inoculated with E. coli O157:H7 were used to ascertain the best conditions for microbial reduction or inactivation. The effect of NEO water pH (7.5 or 6.5), washing treatment time (15 min, 30 min or 15-15 min combination (15 min wash followed by a subsequent 15 min rinse for NEO water at pH 6.5 )), at chlorine concentrations of 155 or 200 mg/L and with or without changing washer agitation direction were evaluated and presented in Table 1. Of the four factors studied, increasing the NEO water chlorine concentration from to 200 mg/L did not result in significant reductions of E. coli O157:H7 populations on romaine lettuce leaves (p>0.05). Reducing NEO water pH from 7.5 to 6.5 and increasing treatment times from 15 min to 30 min significantly increased reductions (p0.05). Changing the washer direction always led to higher reductions when all other factors were constant, however, most of these increases were not significantly different (p>0.05).