Progress 05/15/02 to 05/15/07

Outputs
OUTPUTS: We conducted surveillance and epidemiologic studies in order to determine the points during production and processing of specific fruits and vegetables where pathogens are introduced, and the effect that certain production, processing, and environmental factors may have on contamination. A second objecive of the overall research was to characterize microbial survival, growth, and contamination mechanisms on specific commodities of importance to Florida, as well as the environoment, including microbial interactions within populations. Once assessment of potential hazards and associated commodities was completed, the next objective accomplished was the development and testing of intervention strategies that may be applied during production and/or processing to eliminate or control pathogen contamination in these products. An important component of this particular project was to extend this knowledge effectively and efficiently by developing educational materials on food safety of fruits and vegetables for the following constituencies: university undergraduate and graduate food science students; fruit and vegetable growers, packers, distributors, processors, and consumers. We utilized and tested a variety of delivery methods, including extension publications, distance education modules, face-to-face workshops, traditional classroom courses, and technology transfer symposia. PARTICIPANTS: Over the life of this project, we have worked with many collaborators, mostly those that conduct research in fruit and vegetable food safety. Representative partner organizations include University of California, Davis; Cornell University; Texas A&M University; North Carolina State University; University of Georgia; and others. Additionally, particularly in the area of outreach, we have partnered with the following trade organizations: United Fresh (formerly UFFVA and IFPA); GMA; Florida Tomatoe Board; and Florida Fruit and Vegetable Association. In some cases, we have worked with Florida Cooperative Extension county agents in the area of field training to industry. Additionally, 6 graduate students at the University of Florida have been fully or partially supported by these funds; this has had a significant (and continued) impact on the available and well-trained pool of expertise in the area of produce safety and defense. TARGET AUDIENCES: Fruit and vegetable producers, packers and processors are the target audience for this research, along with equipment manufactureres and other suppliers that serve these industries (sanitation chemicals, packaging, training, etc.). Other university and government scientists that work in the area of produce safety are targeted for this information dissemination, as well, as this research adds to the body of knowledge in the discipline. County extension agents have been both target audiences, as well as training partners in some cases for this information. Finally, and perhaps most importantly, we expect that consumers will ultimately benefit from the enhanced food safety of fruit and vegetable products.

Impacts
An understanding of the extent of natural contamination of fruits and vegetables from Florida farms with human pathogenic bacteria,an understanding of ecological and environmental factors that contribute to contamination of fruits and vegetables with human pathogenic bacteria, and an understanding of the effectiveness of interventions that prevent or remove contamination from fruits and vegetables. This year, many of the studies focused on packinghouse facilities and tomatoes for the fresh market. The recovery, survival and impact of Shigella spp. contamination on both tomatoes and oranges was investigated, Several studies examined the efficacy of chlorine treatment of flume water for eliminating Salmonella spp. from inoculated wounds and intact surfaces, using treatment conditions (free chlorine level, pH, and flume water temperatures) currently utilized in Florida fresh tomato packinghouses. Clearly, water chlorination cannot be relied upon to eliminate contamination of tomato fruit by Salmonella, particularly if these bacteria have gained entry into the fruit through wounds prior to sanitation. Any tomatoes that have wounds such as punctures, cuts or scrapes must be culled at the packinghouse to minimize the chance of Salmonella contamination. Stem scars are a naturally occurring consequence of harvesting tomatoes and therefore cannot be avoided. However, this study suggests stem scars, as with the wounds examined in this study, cannot be readily be disinfected through the use of the industry standard sanitizer, sodium hypochlorite. Thus, it is imperative for tomato growers to minimize or prevent contamination through the use of good agricultural practices prior to and during harvesting. Additionally, we have initiated a program, in support of mechanical harvesting of oranges, to evaluate the effect of various harvesting methods on the surface microflora of fruit.

Publications

• Jackson, C., Archer, D.L., Goodrich-Schneider, R., Gravani, R.B., Bihn, E.A., and Schneider, K.R. 2007. Determining the Effect of Good Agricultural Practices Awareness on Implentation: A Multi-state Survey. Food Protection Trends. Vol 27(9):684-693.
• Goodrich, R., Danyluk, M., Ehsani, R. and Friedrich, L. 2007. The effect of mechanical harvesting on the microflora of citurs fruit and juice. Proc. Fla. State Hort. Soc. 120:115-118.
• Warren, B.R., Yuk, H-G., and Schneider, K.R. 2007. Survival of Shigella sonnei on smooth tomato surfaces, in potato salad and in raw ground beef. Int. J. Food Microbiol. 116:400-404.
• Simmons, K., Harrison, M.A., Hurst, W.C., Harrison, J., Brecht, J.K., Schneider, K.R., Simonne, A. and Rushing, J. 2007. Survey of Food Defense Practices in Produce Operations in the Southeast. Food Protection Trends. 27(3):174-184.
• Mahovic, M.J., Schneider, K.R., Cordasco, K. and Brecht, J.K. 2007. Salmonella Recovery from Tomato Fruit Surfaces as Affected by Ethylene. HortTechnol. 17(1):52-55.
• Yuk, H.G., Warren, B.R. and Schneider, K.R. 2007. Effects of Labeling Tomato Surfaces Using a Low Energy Carbon Dioxide Laser on Infiltration and Survival of Salmonella spp. HortTechnol. 17(1):67-71.
• Warren, B.R., Rouseff, R.L., Schneider, K.R. and Parish, M.E. 2007. Identification of Volatile Sulfur Compounds Produced by Shigella sonnei using Gas Chromatography - Olfactometry. Food Control. 18:179-182.

Progress 10/01/02 to 10/01/03

Outputs
OBJECTIVES: 1. To conduct surveillance and epidemiologic studies in order to determine the points during production and processing of specific fruits and vegetables where pathogens are introduced, and the effect that certain production, processing, and environmental factors may have on contamination. 2. To characterize microbial survival, growth, and contamination mechanisms on specific commodities of importance to Florida, as well as the environment, including microbial interactions within populations. 3. To develop and test management and intervention strategies that may be applied during production and/or processing to eliminate or control pathogen contamination in these products. 4. To develop educational materials on food safety of fruits and vegetables for the following constituencies: university undergraduate and graduate food science students; fruit and vegetable growers, packers, distributors, processors, and consumers. Develop and test a variety of delivery methods, including extension publications, distance education modules, face-to-face workshops, traditional classroom courses, and technology transfer symposia. APPROACH: Generally, we will conduct the necessary research to address Objectives 1-3. We will cooperate and coordinate with Texas A&M University and the University of California, Davis in the completion of all elements of this work as per the Tri-state Consortium Grant (IFAFS). We will develop educational and extension materials in a manner to make the materials available to the widest audience possible, again cooperating and coordinating fully with our partner universities. Specifically, the approach to this project is set forth in the IFAFS grant 'Improving the Safety of Fruits and Vegetables: A Tri-state Consortium.' PROGRESS: 2002/10 TO 2003/10 Work performed in 2002/2003 was designed to evaluate the recovery of Salmonella spp. from tomato, stainless steel, polyvinyl chloride (PVC), sponge roller, conveyor belt and unfinished oak surfaces. Fruit and material surfaces were maintained at specific temperatures and relative humidity (RH), 30oC/80RH, 20oC/60RH and 20oC/90RH for 28 days. Results show the importance of a regular sanitation program for surfaces, since Salmonella could survive for weeks on tomato and packing line surfaces in an accommodating environment, thus increasing the risk of foodborne illness in fresh-market tomatoes. Additionally, enrichment protocols for isolating Shigella spp. found in the FDA's (1998) Bacteriological Analytical Manual, the Compendium of Methods for the Microbiological Examination of Food, and enrichment in brilliant green bile glucose broth were compared both with and without natural background microflora. Shigella Plating Medium was evaluated for the isolation of Shigella spp. against Salmonella-Shigella agar and MacConkey agar. Furthermore, tomato rinses were evaluated using a newly developed FTA filtration/nested PCR method. Grant participants attend a GAPs summit meeting facilitated by Cornell University. Five educational workshops have been conducted in Florida focusing biosecurity.

Impacts
As research results become available, they are transferred to growers and packers through workshops and trade associations. For example, optimal parameters for chlorine efficacy have been shared with California growers/packers directly.

Publications

• Bartz, J., K. Schneider, S. Sargent and K. Felkey. 2002. Addressing Microbial Hazards in Tomato Fruit After Harvest. Florida Tomato Institute Proceedings, Publication # Pro 519/Citrus & Vegetable Magazine. Extension Publication.
• K. Felkey, D.L. Archer, J.A. Bartz and K.R. Schneider. (2004) The Efficacy of Chlorine for Sanitizing Tomato Surface Wounds Contaminated with Salmonella spp. In preparation.
• Warren, B.R., M.E. Parish and K.R. Schneider. 2004. Comparison of Chromagenic Shigella spp. Plating Medium with Standard Media for the Recovery of S. boydii and S. sonnei from Tomato Surfaces. Appl. Environ. Microbiol. In review.
• Warren, B.R., M.E. Parish and K.R. Schneider. 2004. Comparison of Conventional Culture Methods and FTA Filtration-Nested PCR for the Detection of Shigella spp. on Tomato Surfaces. In preparation.

Progress 10/01/01 to 10/01/02

Outputs
The survey of strawberries, tomatoes, cantaloupes and oranges for Salmonella, Shigella, and generic Escherichia coli was completed. No Shigella or Salmonella were found on fruit, however Salmonella was found in soil and water samples from tomato harvesting areas. Generic E. coli was found on post-harvest strawberries, post-packed oranges and packing house environment, in soil and water from all growing areas, and on 10% of pre-harvest cantaloupes. The efficacy studies on chlorine as a sanitizer were conducted to determine optimal pH and temperature parameters for disinfection and will be published. Stem scars, scrapes, and punctures protected Salmonella on tomatoes from chlorine. Three educational workshops have been conducted in two states, California and Florida featuring water quality, GAPs, and biosecurity.

Impacts
As research results become available, they are transferred to growers and packers through workshops and trade associations. For example, optimal parameters for chlorine efficacy have been shared with California growers/packers directly.

Publications

• Archer, DL, Schneider, KR, and Schmidt, RH. 2002. Can HACCP and other existing systems assure protection from terrorism against the food supply? J. Assoc. Food and Drug Officials 66(3):94-102.