Study type: Medical/biological study (experimental study)

Destruction and injury of Escherichia coli during microwave heating under vacuum. med./bio.

Published in: J Appl Microbiol 2005; 98 (2): 498-506

Aim of study (acc. to author)

To study the effect of 2450 MHz microwave irradiation under vacuum (vacuum microwave) on survival and injury of Escherichia coli compared with conventional heating in a water bath under vacuum and to search for possible nonthermal effects associated with vacuum microwave.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 2.45 GHz
Exposure duration: for temperature < 53°C, treatment continued until 2 log reduction in bacterial population was achieved; for temperature > 53°C treatment was continued until no microorganisms survived
Exposure 2: 2.45 GHz
Exposure duration: for temperature < 53°C, treatment continued until 2 log reduction in bacterial population was achieved; for temperature > 53°C treatment was continued until no microorganisms survived

Exposure 1

Main characteristics
Frequency 2.45 GHz
Exposure duration for temperature < 53°C, treatment continued until 2 log reduction in bacterial population was achieved; for temperature > 53°C treatment was continued until no microorganisms survived
Modulation
Modulation type unspecified
Exposure setup
Exposure source
Setup Glass containers placed in microwave oven as well as in water bath were filled with 700-900 ml of peptone water
Parameters
Measurand Value Type Method Mass Remarks
power 711 W - cf. remarks - ± 20 W

Exposure 2

Main characteristics
Frequency 2.45 GHz
Exposure duration for temperature < 53°C, treatment continued until 2 log reduction in bacterial population was achieved; for temperature > 53°C treatment was continued until no microorganisms survived
Modulation
Modulation type unspecified
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
power 510 W - cf. remarks - ± 5 W

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

Although temperature within experiment and between treatments were kept constant, data (activation energy for E. coli destruction and z values (temperature sensitivity curves of E. coli)) of vacuum microwave treatments and water bath heating were different, suggesting that the impact of temperature on destruction rate of E. coli was different when microwaves were the medium of heat transfer.

Study character:

Study funded by

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