Thesis
Ultraviolet (UV) radiation inactivation of Cronobacter sakazakii in dry infant formula observed using Fourier transform infrared spectroscopy and electron microscopy
Washington State University
Master of Science (MS), Washington State University
2011
Handle:
https://hdl.handle.net/2376/102433
Abstract
Cronobacter sakazakii is an opportunistic pathogen associated with dry infant formula which poses a high risk to low birth weight neonates. In the current study, inactivation of C. sakazakii in dry infant formula by ultraviolet (UV) radiation alone and in combination with heat treatment at temperatures of 55, 60 and 65o C were applied. UV radiation with doses in a range of 12.1 to 72.8 kJ/m2 at room temperature had a significant effect on the inactivation of C. sakazakii in dry infant formula (p<0.05). UV radiation of 48.6 kJ/m2 in combination of 55 and 60o C hot water treatment decreased D55 and D65 values for C. sakazakii in reconstituted infant formula. UV radiation doses of 48.6 kJ /m2 at room temperature in combination with 55o C and 65o C hot water treatment each demonstrated a synergistic inactivation effect. Possible inactivation mechanisms were investigated using vibration spectroscopy observing chemical changes to the cell membrane. Infrared spectroscopy was able to detect significant changes in protein, lipid and nucleic acid structures as a result of treatments. Scanning and transmission electron microscopy were employed to investigate changes on surface and inner structure of cells after exposure to UV radiation.
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Details
- Title
- Ultraviolet (UV) radiation inactivation of Cronobacter sakazakii in dry infant formula observed using Fourier transform infrared spectroscopy and electron microscopy
- Creators
- Qian Liu
- Contributors
- Barry G. Swanson (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Food Science, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; Pullman, Wash. :
- Identifiers
- 99900525028101842
- Language
- English
- Resource Type
- Thesis