Dielectric Property Study of Bacillus cereus Spores at Microwave Frequency Region

Study on the dielectric phenomena of cells is critical to the further understanding of electromagnetic effect on cells. The dielectric properties of Bacillus cereus spores were measured for frequencies ranging from 500 to 8500 MHz using coaxial-line probe technology. The influence of Bacillus cereus spores concentration on the dielectric spectroscopy was explored at microwave frequency region. The results showed that the dielectric constant of the sample with Bacillus cereus spores and blank decreased with increasing frequency, especially at higher frequencies. The loss factor had a minimum of about 3420 MHz. What is more, when the frequency was lower than 3420 MHz, the dielectric constant of Bacillus cereus spores was lower than that of blank. While the loss factor and loss tangent were higher than that of blank. There was a more significant change for the loss factor than the dielectric constant between the Bacillus cereus spores and blank. Thus, the dielectric constant can be an indicator in Bacillus cereus spores qualitative analysis.