To compare the killing efficacy and the effects exerted by conventional heating and microwaves on structural and molecular components of Bacillus subtilis spores.
The spore damage was investigated by electron microscopy and by measuring the amount of dipicolinic acid released by treated spores.
Modulation type: CW
Exposure duration: 2, 4, 6, 8, 10, 14 and 20 min
|Exposure duration||2, 4, 6, 8, 10, 14 and 20 min|
|Additional info||Reference article: Metaxas, A.C. and Meredith, R.J. (1993) Multimode oven applicators. In Industrial Microwave Heating ed. Peregrinus, P. pp. 130-150. London, UK: Institute of Electrical & Electronics Engineer.|
|Additional info||A rectangular waveguide (7.2 x 3.4 cm) was connected to another identical adapter through a brass waveguide straight section. Two empty borosilicate glass spheres (4 mm outer diameter) were introduced into the test tubes and held to the bottom by a coiled, thin walled teflon tube (0.9 mm diameter x 50 mm). For comparison purpose, test tubes filled with water were placed in a commercial multimode oven (34.5 x 34 x 23 cm internal capacity) with a nominal working power of 750 W at 2.45 GHz. The samples immersed into the boiling water were heated for the same time intervals as the samples in the waveguide.|
|power||80 W||-||unspecified||-||input power to the waveguide|
|electric field strength||36 V/cm||-||unspecified||-||± 5 V/cm|
Microwaves are as effective as conductive heating in killing the spores, but the microwave electric field induces changes in the structural and/or molecular components of spores that differ from those attributable only to heat.