[Show abstract][Hide abstract] ABSTRACT: The consumption of fresh tomatoes has been linked to numerous foodborne outbreaks involving various serovars of Salmonella enterica. Recent advances in our understanding of plant-microbe interactions have shown that human enteric pathogenic bacteria, including S. enterica, are adapted to survive in the plant environment. In this study, tomato plants (cv. Micro-Tom) grown in sandy loam soil from Virginia's Eastern Shore (VES) were inoculated with S. enterica serovars to evaluate plausible internalization routes and to determine if there is any niche fitness for certain serovars. Both infested soil and contaminated blossoms can lead to low internal levels of fruit contamination with Salmonella. Salmonella serovars demonstrated great ability to survive in environments under tomato cultivation, not only in soil, but also on different parts of the tomato plant. Of the five serovars investigated, serovars Newport and Javiana were dominant in sandy loam soil; while Montevideo and Newport were more prevalent on leaves and blossoms. It was also observed that serovar Typhimurium survived poorly in all the plant parts examined here, suggesting postharvest contamination routes would be more likely for S. Typhimurium contamination of tomato fruit. Conversely, serovar Newport was the most prevalent serovar recovered in both the tomato rhizosphere and phyllosphere. Plants that were recently transplanted (within 3 days) had an increase in observable internalized bacteria, suggesting that plants were more susceptible to internalization right after transplant. These findings suggested that Salmonella serovar and plant growth stage were two important factors for internalization through the root system.
Applied and environmental microbiology 02/2013; · 3.69 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: High tunnels and protected horticultural structures provide organic and conventional growers with an economic means for extending the harvest season of fresh fruits and vegetables in a wide range of climate zones in North America and elsewhere. This report focuses on benefits associated with high tunnel production of fresh organic produce, including recent data on phytonutrient quality. In addition, this report discusses concerns and knowledge gaps associated with the use of composts and manures relative to food safety of fresh produce and survival of enteric pathogens in the moist, cool, reduced ultraviolet conditions often prevalent in high tunnels during cool-season production. The role of preplant and production elements of Good Agricultural Practices and Good Handling Practices applicable to high tunnel systems is provided.