Food and Bioprocess Technology

, 3:93

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


  • Kathiravan Krishnamurthy
    • Department of Food and Animal SciencesAlabama A&M University
  • Jagdish C. Tewari
    • Department of Fiber Science and Apparel DesignCornell University
  • Joseph Irudayaraj
    • Department of Agricultural and Biological EngineeringPurdue University
    • Department of Agricultural and Biological Engineering, The Huck Institutes of the Life SciencesThe Pennsylvania State University
    • Pennsylvania State University
Original Paper

DOI: 10.1007/s11947-008-0084-8

Cite this article as:
Krishnamurthy, K., Tewari, J.C., Irudayaraj, J. et al. Food Bioprocess Technol (2010) 3: 93. doi:10.1007/s11947-008-0084-8


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.


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

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© Springer Science + Business Media, LLC 2008