salmonella surface characterization and adhesion to food and other surfaces l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Salmonella surface characterization and adhesion to food and other surfaces PowerPoint Presentation
Download Presentation
Salmonella surface characterization and adhesion to food and other surfaces

Loading in 2 Seconds...

play fullscreen
1 / 23

Salmonella surface characterization and adhesion to food and other surfaces - PowerPoint PPT Presentation


  • 92 Views
  • Uploaded on

Salmonella surface characterization and adhesion to food and other surfaces. Samantha Begnoche Advisor: Dr. Sharon Walker Bioengineering Research Institute for Technical Excellence August 20, 2009. Background. From 1988 – 1995 reported cases varied between 40,000 and 50,000

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Salmonella surface characterization and adhesion to food and other surfaces' - gale


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
salmonella surface characterization and adhesion to food and other surfaces

Salmonella surface characterization and adhesion to food and other surfaces

Samantha Begnoche

Advisor: Dr. Sharon Walker

Bioengineering Research Institute for Technical Excellence

August 20, 2009

background
Background
  • From 1988 – 1995 reported cases varied between 40,000 and 50,000
  • Previous projects limited to genotypic nature
  • Objective: Understand surface chemistries and transport kinetics of Salmonella to keep future outbreaks to a minimum.
some facts
Some Facts
  • Still, approximately 40,000 cases of Salmonella poisoning reported annually
  • ~400 deaths annually are result of Salmonella
  • Children, elderly, and immune diseased are most vulnerable
goals
Goals
  • Short-term work: Characterize strains’ surface chemistries
  • Three strains focused on:
    • SGSC 4910 (newport)
    • SGSC 2377 (enteritidis)
    • SA 5983 (typhimurium)

S. typhimurium respresentation

Provided by Berat Haznedaroglu

methods

Incubation

Centrifuge

Inoculation

Methods
  • Bacteria Preparation

- Inoculate bacteria night before

- Preculture in LB media for specified time

- Harvest – centrifuge, wash in KCl twice, resuspend for stock solution

characterization methods
Characterization methods
  • Viability
    • Mix stock solution and dye. Vortex and wait 15 minutes. Count live (green) and dead (red).
  • Size measurement
    • Measure length and width using images taken with phase contrast microscope. Calculate spherical radii.
characterization methods7
Characterization methods
  • Hydrophobicity measurement
    • Using MATH test with n-dodecane, measure the percentage of cells that choose the hydrocarbon versus the electrolyte condition. <40% is hydrophilic
  • Electrophoretic mobility measurement
    • Using ZetaPALS, calculate the electrophoretic mobility and zeta potential from a solution diluted to an optical density of .200 to .225 to result in a concentration of about 107 cells.
parallel plate flow chamber methods
Parallel plate flow chamber methods
  • Parallel plate flow chamber
    • Take picture of cells flowing through at 20 second intervals for set amount of time
    • Number of cells depositing on the surface is counted and plotted as a function of time
    • Adhesion rate is calculated from slope
slide9

Fluorescent light

Parallel plate flow chamber system

Fluorescent light

viability results
Viability Results
  • SA 5983:
    • 1 mM KCl: 81.5 ± 1.7%
    • 10 mM KCl: 87.4 ± 2.1%
    • 100 mM KCl: 89.7 ± 11.8%
size measurement results
Size Measurement Results
  • SA 5983: 0.326 ± 0.113 µm
  • SGSC 4910: 0.368 ± 0.145 µm
  • SGSC 2377: 0.317 ± 0.067 µm
parallel plate results
Parallel Plate Results
  • SA 5983 exhibits no attachment for 1 mM KCl solution.
  • Amount of deposition is expected to increase with increasing ionic strength
  • Also expected to increase at lower rates
parallel plate flow chamber results
Parallel Plate Flow Chamber Results

* Data is representative as work is ongoing

closing
Closing
  • Three strains are very different
  • As of yet, no inferences can be drawn connecting phenotypic nature and adhesion.
further work
Further work

1

  • 96 well plate coated to mimic surface layer of foods
  • Ultimately: identify properties that inhibit adhesion and a solution to foodborne outbreaks

2

3

references
References
  • http://www.clker.com/search/cartoon+food/3
  • http://drjean.org/html/monthly_act/act_2005/09_Sep/pg04.html
  • http://www.steveklotz.com/blog/?m=200609
  • Yates, Walker, Bianchi. Ensuring Food Safety from Pathogens: Farm to Fork.
acknowledgments
Acknowledgments
  • Thank you, especially, Dr. Sharon Walker and Olgun Zorlu for teaching me everything that you have and making it run so smoothly.
  • Thank you very much, Dr. Sharon Walker’s lab group, including Gexin Chen, Indranil Chowdury, Amy Gong, Berat Haznedaroglu, Ian Marcus, Brian Perez, and Chad Thomsenfor all the help in the lab.
  • Thank you, Jun Wang, for all the work done to make this a great summer for all of us.
  • Thank you, National Science Foundation for funding opportunities like this one for college students like myself.