Related Experiment Video
Updated: Aug 20, 2026

Visualization of UV-induced Replication Intermediates in E. coli using Two-dimensional Agarose-gel Analysis
Published on: December 21, 2010
Destruction and injury of Escherichia coli during microwave heating under vacuum
1Food Nutrition and Health, University of British Columbia, Vancouver, BC, Canada.
Aims:
To study the effect of 2450 MHz microwave radiation under vacuum (vacuum microwave or VM) on survival and injury of Escherichia coli and to search for possible nonthermal effects associated with VM.
Methods And Results:
Destruction kinetics of E. coli in peptone water were determined in a continuous-flow vacuum system, heated by convection heating in a water bath or with microwaves (VMs). Vacuum was used to control the boiling point of water and to maintain temperature in the bacterial suspensions at specified levels (49-64 degrees C).
Conclusions:
z-Value in the water bath treatment was 9.1 degrees C while for VM at 510 and 711 W it was 6.2 and 5.9 degrees C, suggesting that E. coli is more sensitive to temperature changes under microwave heating. Arrhenius calculations of the activation energies of the destruction reactions suggest that the mechanism of destruction in VM may be different from that of conventional heat. The number of injured micro-organisms showed no significant differences among treatments.
Significance And Impact Of The Study:
The impact of temperature on E. coli destruction was different when microwaves were the medium of heat transfer, suggesting the existence of factors other than heat contributing to the lethal effect of VM.
Related Concept Videos
Methods of Sterilization I: Physical Methods
Steam sterilization uses non-toxic, low-cost moist heat in the form of saturated steam under pressure, which is fast, microbicidal, and sporicidal, and quickly warms and penetrates fabrics. Autoclaves, or steam sterilizers, expose each item to direct steam contact for a predetermined time at the necessary...
Physical Methods for Controlling Microbial Growth: Temperature
Bacterial Gastroenteritis
Physical Methods for Controlling Microbial Growth: Radiation and Filtration
Methods of Sterilization II: Chemical Methods
Using chemical sterilization rather than heat to clean out equipment is recommended. It eradicates and removes all bacteria,...

