Microscopic and Spectroscopic Evaluation of Inactivation of Staphylococcus aureus by Pulsed UV Light and Infrared Heating

  • Kathiravan Krishnamurthy
  • Jagdish C. Tewari
  • Joseph Irudayaraj
  • Ali Demirci
Original Paper

Abstract

Pulsed UV light and infrared heat-treated Staphylococcus aureus cells were analyzed using transmission electron microscopy to identify the cell damage due to the treatment process. A 5-s treatment with pulsed UV light resulted in complete inactivation of S. aureus even after enrichment. The temperature increase during the pulsed UV light treatment was insignificant, which suggested a nonthermal treatment. S. aureus was also infrared heat treated using an infrared heating system with six infrared lamps. Five milliliters of S. aureus cells in phosphate buffer was treated at 700°C lamp temperature for 20 min. The microscopic observation clearly indicated that there was cell wall damage, cytoplasmic membrane shrinkage, cellular content leakage, and mesosome disintegration after both pulsed UV light and infrared treatments. Fourier transform infrared microspectrometry was successfully used to classify the pulsed UV light and infrared heat-treated S. aureus by discriminant analysis.

Keywords

Pulsed UV light Infrared heating Electron microscopy Fourier transform infrared spectroscopy Inactivation mechanism Staphylococcus aureus 

Copyright information

© Springer Science + Business Media, LLC 2008

Authors and Affiliations

  • Kathiravan Krishnamurthy
    • 1
  • Jagdish C. Tewari
    • 2
  • Joseph Irudayaraj
    • 3
  • Ali Demirci
    • 4
    • 5
  1. 1.Department of Food and Animal SciencesAlabama A&M UniversityNormalUSA
  2. 2.Department of Fiber Science and Apparel DesignCornell UniversityIthacaUSA
  3. 3.Department of Agricultural and Biological EngineeringPurdue UniversityWest LafayetteUSA
  4. 4.Department of Agricultural and Biological Engineering, The Huck Institutes of the Life SciencesThe Pennsylvania State UniversityUniversity ParkUSA
  5. 5.Pennsylvania State UniversityUniversity ParkUSA

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