2012 Annual Report 1a.Objectives (from AD-416): ARS is interested in integrated approaches to improve produce safety while maintaining quality. The Cooperator, University of Maryland, is interested in evaluating the produce surface characteristics and sanitizer efficacy on pathogen reduction. The Cooperator has the expertise and infrastructure to effectively conduct the proposed research activities. 1b.Approach (from AD-416): ARS will acquire the basic knowledge of the factors influencing sanitizer degradation, pathogen attachment and internalization during leafy greens and tomato wash process. The Cooperator will provide the expertise in anti-microbial, surface adsorption, topography, and other characteristics in relation to sanitizer performance on pathogen reduction. 3.Progress Report: Tomato packing houses in Florida were audited for wash water quality and concentration of active sanitizer ingredient during tomato dump tank wash operations. The correlations among water quality measurement parameters were determined, and functional limits where wash water replenishment or replacement is needed were assessed. Laboratory tests were conducted to evaluate the dynamic interaction between chlorine concentration and oxygen reduction potential (ORP) as impacted by organic load simulated with tomato juice. In other studies the effects of various factors on incidence of Salmonella infiltration were investigated. Factors assessed included tomato variety, post-stem removal time, and the temperature differential between tomato pulp and bacterial suspension. Information generated has been shared with the produce industry and the FDA for establishing science-based tomato handling standards to prevent pathogen contamination and internalization.