What are the effective ORP ranges? Detailed determinations of effective ORP values for microorganisms of concern to postharvest quality, shelf life, and food safety are not yet available in a scientifically reviewed form. Studies completed to date strongly support the establishment of 650mV is consistent with the standards that were developed and have been used in parts of Europe since mid-1980 for municipal drinking water quality. Maintaining this ORP will provide rapid inactivation of soft-rot Erwinia and Pseudomonas bacteria as well as other non-spore-forming microorganisms. Resistant fungal spores or parasitic oocysts will require higher ORP values and/or longer contact times. Trevor V. Suslow, Ph.D. U.C. Davis