Study type: Medical/biological study (experimental study)

Sensitivities of germinating spores and carvacrol-adapted vegetative cells and spores of Bacillus cereus to nisin and pulsed electric field treatment med./bio.

By: Pol IE, van Arendonk WCG, Mastwijk HC, Krommer J, Smid EJ, Moezelaar R
Published in: Appl Environ Microbiol 2001; 67 (4): 1693-1699
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Aim of study (acc. to author)

To investigate the sensitivity and viability of spores and cells of the bacterium Bacillus cereus to nisin, carvacrol, and pulsed electric field treatment.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 980 Hz
Modulation type: pulsed
Exposure duration: 10 min
influence on spores
Exposure 2: 980 Hz
Modulation type: pulsed
Exposure duration: 10 min
Sensitivity of germinating spores
Exposure 3: 980 Hz
Modulation type: pulsed
Exposure duration: 10 min
influence of preincubation
Exposure 4: 980 Hz
Modulation type: pulsed
Exposure duration: 10 min
influence of preincubation on vegetative cells

Exposure 1

Main characteristics
Frequency 980 Hz
Type
Exposure duration 10 min
Additional info influence on spores
Modulation
Modulation type pulsed
Pulse width 2 µs
Pulse type rectangular
Exposure setup
Exposure source
  • not specified
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 53 kV/cm unspecified unspecified - -

Exposure 2

Main characteristics
Frequency 980 Hz
Type
Exposure duration 10 min
Additional info Sensitivity of germinating spores
Modulation
Modulation type pulsed
Pulse width 2 µs
Exposure setup
Exposure source
  • not specified
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 27 kV/cm unspecified unspecified - -

Exposure 3

Main characteristics
Frequency 980 Hz
Type
Exposure duration 10 min
Additional info influence of preincubation
Modulation
Modulation type pulsed
Pulse width 2 µs
Exposure setup
Exposure source
  • not specified
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 27 kV/cm unspecified unspecified - -

Exposure 4

Main characteristics
Frequency 980 Hz
Type
Exposure duration 10 min
Additional info influence of preincubation on vegetative cells
Modulation
Modulation type pulsed
Pulse width 2 µs
Exposure setup
Exposure source
  • not specified
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 53 kV/m - - - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

Neither inactivation nor heat sensivity of Bacillus cereus spores were affected by treatment with nisin and/or pulsed electric fields. Whereas germinating spores were found to be sensitive to pulsed electric fields and even more sensitive to nisin treatment. The effect of nisin on germinating spores was comparable to heat inactivation. The viability of vegetative Bacillus cereus cells, preincubated with carvacrol, was dramatically reduced by nisin treatment. Whereas spores grown in the presence of carvacrol were not affected by nisin and/or pulsed electric filed treatment.

Study character:

Study funded by