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).