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THE BACTERICIDAL EFFECT OF ULTRAVIOLET RADIATION ON ESCHERICHIA COLI IN LIQUID SUSPENSIONS
1Laboratory of Plant Physiology, Department of Botany, University of Wisconsin, Madison.
The Journal of General Physiology
|October 30, 2009
Summary
This study introduces a novel method for irradiating bacteria in liquid suspension using ultraviolet radiation. The technique enables precise measurement of the energy required for bacterial inactivation, accounting for protective effects.
Area of Science:
- Microbiology
- Biophysics
- Photobiology
Background:
- Irradiating bacteria in liquid suspension presents challenges in achieving uniform exposure and accurate dosage.
- Previous methods lacked standardized approaches for quantifying ultraviolet radiation's effect on bacterial inactivation.
Purpose of the Study:
- To develop and validate a method for irradiating bacteria in liquid suspension for precise ultraviolet inactivation studies.
- To establish a formula for calculating the energy required for bacterial inactivation, correcting for protective factors.
- To investigate the impact of bacterial age and preparation on ultraviolet inactivation sensitivity.
Main Methods:
- Utilized a specially balanced physiological salt solution and a unique exposure cell design with thorough stirring for uniform radiation exposure.
- Employed dense bacterial suspensions for near-complete absorption of incident ultraviolet radiation.
- Developed a formula to calculate inactivation energy from survival ratios, incorporating a correction for non-viable organisms.
Main Results:
- Successfully demonstrated a method for irradiating bacteria in liquid suspension, allowing for the study of sub-lethal doses.
- Provided data on the ultraviolet inactivation of various cultures of Escherichia coli (E. coli), including different ages and preparation methods.
- Presented a formula for calculating the energy required for bacterial inactivation, validated against existing data.
Conclusions:
- The developed method offers a reliable approach for studying ultraviolet radiation effects on bacteria in suspension.
- Bacterial age and preparation significantly influence sensitivity to ultraviolet inactivation.
- The study contributes to understanding the mechanism of ultraviolet radiation action on microorganisms.
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