Nonthermal killing effect of microwave irradiation

Microwave Effects on Soluble Substrate and Thermophilic Digestibility of Activated Sludge

“…The second microwave pretreatment was the athermal pretreatment. In the case of microwave athermal tests (A, the same microwave oven was used but with modifications in order to maintain the temperature low and constant in the TWAS being irradiated (Coelho et al, 2011;Sato et al, 1996;Welt et al, 1994 ). Appendix 1 depicts the oven set-up.…”

“…Several studies claim that there is no evidence of an athermal microwave effect and that the biocidal effects of microwave either are entirely attributable to heating or are indistinguishable from external heating (Fujikawa et al, 1992;Jeng et al, 1987;Welt et al, 1994). The difficulty in dissociating microwave irradiation from temperature increase and in isolating thermal from potentially athermal effects has hindered the scientific community from resolving these differences (Banik et al, 2003;Sato et al, 1996). This obstacle was circumvented by Sato et al (1996), who devised a system that managed to isolate the microwave irradiation and the increase in temperature in the irradiated medium.…”

“…The difficulty in dissociating microwave irradiation from temperature increase and in isolating thermal from potentially athermal effects has hindered the scientific community from resolving these differences (Banik et al, 2003;Sato et al, 1996). This obstacle was circumvented by Sato et al (1996), who devised a system that managed to isolate the microwave irradiation and the increase in temperature in the irradiated medium. Given that the magnitude of the thermal effects is large enough to obscure the existence of athermally driven phenomena, the latter can now be more adequately addressed (Coelho et al, 2011).…”

Assessment of microbial viability in municipal sludge following ultrasound and microwave pretreatments and resulting impacts on the efficiency of anaerobic sludge digestion

“…Following MW pretreatment and conventional heating of Escherichia coli (K-12 IFO 3301) at 35, 45, 47, and 50°C, it was found that there was a non-thermal killing effect by MW pretreatment over 45°C; moreover, it was determined that the rate of bacterial death could be accelerated by increasing the MW power. However, cell destruction was not possible at MW intensities of 35 W nor at temperatures below 35°C (Sato et al 1996).…”

Nonthermal Microwave Radiations Affect the Hypersensitive Response of Tobacco to Tobacco Mosaic Virus

“…On the other hand, in the last few decades several researchers have outlined direct or water-mediated nonthermal effects of EMFs on free ions, on rate and direction of biochemical reactions (such as the melatonin/serotonin balance), and on cell replication (Adey, 1993;Cherry, 1998;Devyatkov, 1974;Rai et al, 1999;Sato et al, 1996;Singh et al, 1994;Webb, 1975). Recently, a nonthermal heatshock response to microwaves has been reported: the hypothesized mechanism includes disruption of weak bonds of protein active forms, enhanced production of reactive oxygen species, and interference with cell-signaling pathways (De Pomerai et al, 2000).…”