1a. Objectives (from AD-416):
The objective of this study is to determine if there are phenotypic characterisistics associated with Salmonella Hadar and/or Heidelberg-ground turkey turkey outbreak strains that enhance the ability of these strains to survive in/on poultry. Such characteristics may allow these strains to subsequently induce food-borne illnesses in consumers. The characteristics being studied include increased tolerance to heat, acid, and/or high pressure pasteurization.
1b. Approach (from AD-416):
FSIS will coordinate the identification of approximately 24 Salmonella Hadar and Heidelberg isolates which are appropriate for this study. Ideally these isolates will include related clinical, product and establishment isolates as well as controls. Commercially obtained ground turkey, culture media will be inoculated with the isolates. Separate experiments will be conducted by ARS Scientists and Drexel students to screen the isolates for susceptibility to heat, high pressure and acid.
3. Progress Report:
Identification of phenotypic characteristics affecting enhanced survivability associated with Ground Turkey – Salmonella outbreak strains. The recovery and association of Salmonella with poultry is a key factor that increases the risk for the presence of the bacterium in meat and eggs. The objective of this study is to determine if there are phenotypic characteristics associated with Salmonella Hadar and/or Heidelberg, ground turkey outbreak strains, that enhance the ability of these strains to survive in/on poultry. Such characteristics may allow these strains to subsequently induce food-borne illnesses in consumers. The characteristics being studied include increased tolerance to heat, acid and/or high pressure pasteurization. In collaboration with USDA/FSIS, we evaluated the effect of high pressure pasteurization (HPP) on the fate of Salmonella Hadar and/or Heidelberg associated with ground turkey outbreaks. From among the 35 strains of Salmonella received that were isolated from patients, ground turkey, or attendant environment, 24 strains were selected and individually subjected to HPP. Pressurization at 600 MPa or at 483 MPa for 0.5 to 5 minutes reduced numbers of Salmonella by 2.5 to <6.0 log CFU/ml. Experiments are currently being conducted to evaluate the effect of HPP on the inactivation of Salmonella in a model ground poultry system. Additional studies are also being conducted to evaluate the heat and acid susceptibility of the 24 strains of Salmonella that were previously selected.