title: Effects of nitrogen and potassium fertilization on the susceptibility of tomatoes to post-harvest proliferation of Salmonella enterica.
abstract: Fresh fruits and vegetables are increasingly recognized as vehicles of salmonellosis. Pre- and post-harvest environmental conditions, and physiological, and genetic factors are thought to contribute to the ability of human pathogens to persist in the production environment, attach to, colonize and proliferate in and on raw produce. How field production conditions affect the post-harvest food safety outcomes is not entirely understood. This study tested how varying nitrogen and potassium fertilization levels affected the "susceptibility" of tomatoes to Salmonella infections following the harvest of fruits. Two tomato varieties grown over three seasons under high, medium, and low levels of nitrogen and potassium fertilization in two locations were inoculated with seven strains of Salmonella. Even though the main effects of nitrogen and potassium fertilization on the susceptibility of tomatoes to infections with Salmonella enterica were not statistically significant overall, differences in nitrogen concentrations in plant tissues correlated with the susceptibility of partially ripe tomatoes (cv. Solar Fire) to Salmonella. Tomato maturity and the season in which tomatoes were produced had the strongest effect on the ability of Salmonella to multiply in tomatoes. Tomato phenolics, accumulation of which is known to correlate with rates of the N fertilization, did not inhibit growth of Salmonella in vitro.
authors.affiliation: Department of Soil and Water Science, University of Florida, Gainesville, FL, USA.
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Marvasi
authors.affiliation: Department of Soil and Water Science, University of Florida, Gainesville, FL, USA.
authors.forename: Andrée S
authors.initials: AS
authors.lastname: George
authors.affiliation: Statistics Department, University of Florida, Gainesville, FL, USA.
authors.forename: Mihai
authors.initials: M
authors.lastname: Giurcanu
authors.affiliation: Department of Soil and Water Science, University of Florida, Gainesville, FL, USA.
authors.forename: George J
authors.initials: GJ
authors.lastname: Hochmuth
authors.affiliation: Department of Soil and Water Science, University of Florida, Gainesville, FL, USA.
authors.forename: Jason T
authors.initials: JT
authors.lastname: Noel
authors.affiliation: Department of Soil and Water Science, University of Florida, Gainesville, FL, USA.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Gause
authors.affiliation: Department of Soil and Water Science, University of Florida, Gainesville, FL, USA. Electronic address: maxtep@ufl.edu.
authors.forename: Max
authors.initials: M
authors.lastname: Teplitski
mesh_terms: D049109:Cell Proliferation; D005308:Fertilizers / Q000032:analysis*; D005506:Food Contamination / Q000032:analysis; D005638:Fruit / Q000737:chemistry / Q000254:growth & development / Q000378:metabolism / Q000382:microbiology*; D018551:Solanum lycopersicum / Q000737:chemistry / Q000254:growth & development / Q000378:metabolism / Q000382:microbiology*; D009584:Nitrogen / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism*; D019779:Salmonella enterica / Q000254:growth & development*; D013997:Time Factors
chemical_list: D005308:Fertilizers; D009584:Nitrogen; D011188:Potassium
keywords: Field production conditions; Post-harvest infection; Produce safety; Salmonella enterica; Secondary metabolite