Effect of Microwaves on
            <i>Escherichia coli</i>
            and
            <i>Bacillus subtilis</i>

Goldblith, S.A.; Wang, Daniel I. C.

doi:10.1128/am.15.6.1371-1375.1967

Cited by 73 publications

(10 citation statements)

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“…Woo et al 46 reported that the viable counts of bacteria B. subilis or Escherichia coli were reduced dramatically in the buffer solution when the microwave heating temperature exceeded 60 C. Stout et al 47 measured the thermal exposure time required to produce the fungicidal effects of Legionellaceae in the liquid broth at 60 C, 70 C and 80 C; these were 1.3 min to 10.6 min, 0.7 min to 2.6 min and 0.3 min to 0.7 min, respectively. Goldblith and Wang 40 showed that microwave could cause no destruction of E. coli in the buffer when held below 51 C. In this study, the germicidal effect on the three strains of fungi and bacteria was demonstrated to occur at a liquid temperature above 60 C. Therefore, the minimum temperature for thermal disinfection would be above 60 C for applications to evaporative humidifiers to be used in office buildings, except for the microorganisms that are resistant to heat. The effectiveness of microwave disinfection for evaporative humidifiers in the living place of susceptible people, like hospitals and facilities with elders or children, could be enhanced more efficiently by increasing the temperature above 70 C or 80 C.…”

Section: Discussionmentioning

confidence: 69%

“…38 Many researchers had reported that microwave disinfection would occur as a result of thermal effects by heating dielectric materials. 32,39,40,41 Thus, some researchers had reported that the threshold energy of ionization for water and DNA components of microorganisms is 4-5 eV 42,43 and microwaves would be unable to damage DNA components of microorganisms, because the microwave energy would be too low at 1.02 Â 10 -5 eV.…”

Section: Discussionmentioning

confidence: 99%

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Thermal and non-thermal germicidal effects of microwave radiation on microbial agents

Kang

Kato

2013

Indoor and Built Environment

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To assess possible applications of evaporative humidifier elements of air-conditioning systems, the germicidal effect of microwave irradiation on fungal spores (e.g. Cladosporium herbarum and Fusarium solani), vegetative bacteria and bacterial spores (e.g., Bacillus subtilis) was investigated by this study. A general purpose microwave oven and a specifically assembled microwave source placed in a 2.45 GHz magnetron were used. Initially, the optimal radiation output power and exposure time were determined to achieve the desired germicidal effects using both wet and dry sample filters. The study also investigated whether the germicidal effect could be a direct result of the microwave irradiation or rather a result of the radiation-induced heat. The results of our study have indicated that microbial degradation could be dependent on the fungal strain type, microwave output power, exposure time and sample moisture. Our results have also illustrated that the germicidal effect shown in the experiments could be attributed to the associated rise in temperature particularly above 60℃ during the microwave irradiation of the fungal buffer solutions.

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Section: Discussionmentioning

confidence: 69%

Section: Discussionmentioning

confidence: 99%

Thermal and non-thermal germicidal effects of microwave radiation on microbial agents

Kang

Kato

2013

Indoor and Built Environment

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“…Bacterial deactivation using microwave irradiation showed both thermal and non-thermal effects. Goldblith and Wang [ 7 ] compared the deactivation of Escherichia coli and Bacillus subtilis spores using microwave irradiation versus conventional radiant heating. They suggested that the deactivation of these bacteria resulted from the dielectric heating and did not maintain any secondary effect from the microwave irradiation.…”

Section: Introductionmentioning

confidence: 99%

Mathematical Models of Cobalt and Iron Ions Catalyzed Microwave Bacterial Deactivation

Reznik

Benjamin

Williams

2007

IJERPH

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Time differences for Enterococcus faecalis, Staphylococcus aureus, and Escherichia coli survival during microwave irradiation (power 130 W) in the presence of aqueous cobalt and iron ions were investigated. Measured dependencies had “bell” shape forms with maximum bacterial viability between 1 – 2 min becoming insignificant at 3 minutes. The deactivation time for E. faecalis, S. aureus and E.coli in the presence of metal ions were smaller compared to a water control (4–5 min). Although various sensitivities to the metal ions were observed, S. aureus and E. coli and were the most sensitive for cobalt and iron, respectively. The rapid reduction of viable bacteria during microwave treatment in the presence of metal ions could be explained by increased metal ion penetration into bacteria. Additionally, microwave irradiation may have increased the kinetic energy of the metal ions resulting in lower survival rates. The proposed mathematical model for microwave heating took into account the “growth” and “death” factors of the bacteria, forming second degree polynomial functions. Good relationships were found between the proposed mathematical models and the experimental data for bacterial deactivation (coefficient of correlation 0.91 – 0.99).

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“…T and P are the temperature and power dissipated per unit volume by the EM field in the respective material. In case of nonconductive and nonmagnetic system, the EM power dissipation is due to the dielectric loss which can be describes by [ 37 ]

P = \frac{1}{2} (\overset{E}{true} . \frac{\partial \overset{D}{true}}{\partial t} - \overset{D}{true} . \frac{\partial \overset{E}{true}}{\partial t})

…”

Section: Introductionmentioning

confidence: 99%

Anisotropic Plasmonic Effect on Ag Nanoparticles under Microwave‐Induced Plasma‐in‐Liquid: Insight into Growth Mechanism

Bharti

Bhardwaj

Goyal

2021

Part & Part Syst Charact

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Anisotropic nanoparticles are a potential foundation for emerging materials engineering having anomalous properties often to an extraordinary degree‐enabling widespread new applications. In the bottom‐up approach, isotropic nanoparticles are formed by self‐assembly following the basic packing rule but lack directional interaction. On the other hand, anisotropic nanoparticles involve complex programmability having directional interaction and thus become of utmost interest in science and technology. In this paper, the anisotropic plasmonic effects in silver (Ag) nanoparticles under microwave‐induced plasma‐in‐liquid‐assisted decomposition of saccharides and di‐saccharides following the green chemistry process are investigated. The effect of microwave power, irradiation time, and relative chemical composition has been investigated in detail using extinction spectroscopy and Mie theory. The relationship between extinction curve shape parameter (S) and Mie theory has been established. The extinction spectroscopy and transmission electron microscopy (TEM) study confirm the existence of anisotropic plasmonic effects in Ag nanoparticles following two‐generation growth mechanisms having an average particle size of 2 and 32 nm. This technique offers rapid (20–40 sec) bulk production and is cost/energy effective than the conventional synthesis route.

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Effect of Microwaves on Escherichia coli and Bacillus subtilis

Cited by 73 publications

References 0 publications

Thermal and non-thermal germicidal effects of microwave radiation on microbial agents

Thermal and non-thermal germicidal effects of microwave radiation on microbial agents

Mathematical Models of Cobalt and Iron Ions Catalyzed Microwave Bacterial Deactivation

Anisotropic Plasmonic Effect on Ag Nanoparticles under Microwave‐Induced Plasma‐in‐Liquid: Insight into Growth Mechanism

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