2011 Annual Report 1a.Objectives (from AD-416) To develop techniques to improve food safety and quality of fresh and fresh-cut produce using ultra-sound and other emerging technologies; to investigate the effect of various new sanitizers on pathogen reduction and shelf-life extension of fresh-cut fruits and vegetables; and to gain a greater understanding of how fresh-cut processing conditions affect plant metabolism, microbial growth, and their interactions. 1b.Approach (from AD-416) ARS will acquire the basic knowledge of the factors influencing pathogen transference during lettuce harvesting. The Cooperator will provide the expertise in equipment design and disinfection. Advanced molecular and microbiological techniques will be applied to quantify pathogen concentrations spanning a range of realistic contaminant loads and field conditions; creative engineering approaches will be utilized to optimize coring knife design and develop enhanced sanitation practices. 3.Progress Report Knives used for commercial coring-in-field lettuce harvesting are likely to contact soil and thus serve as vehicles for transmission of food-borne pathogens to the vulnerable cut edges of lettuce tissue. We examined the effect of ultrasound on the fate of E. coli O157:H7 contaminated on coring knives and developed two prototype coring knives. We demonstrated that the two prototype coring knives harbored significantly fewer E. coli O157:H7 cells than the current commercially used one, and were easier to disinfect. Furthermore, the ultrasound treatment on coring knives reduced E. coli O157:H7 counts to below the detection limit. The progress of this project has been closely monitored by the ADODR via frequent contact with the PI at the University of Maryland via conference calls, face-to-face meetings, and e-mails.