Inactivation of Bacillus Spores in Dry Systems at Low and High Temperatures

Molin, Göran

doi:10.1099/00221287-101-2-227

Cited by 12 publications

(5 citation statements)

References 7 publications

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“…Similarly the z-value (var.niger) obtained by various workers using TGE range from 12.9"C to 32°C compared with 21.25"C obtained by our methods (Table 8). The z-value graphs are linear (Figs 6 and 7) and in good agreement with those published by Molin (19776) using the same temperature range. Molin & Ostlund (1976) have shown that spore density affects the rate of kill of spores dried on to glass surfaces heated by infra-red radiation and this is an additional cause of variation between dry-heat killing data.…”

Section: Minutessupporting

confidence: 87%

Thermal Activation and Dry‐heat Inactivation of Spores of Bacillus subtilis MD2 and Bacillus subtilis var. niger

Gurney

Quesnel

1980

Journal of Applied Bacteriology

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Spores of Bacillus subtilis MD2 and Bacillus subtilis var. niger were heat activated for different times at 60° and 80°C. Strain MD2 required considerable heat activation while B. subtilis var. niger did not. Maximum germination rates increased with heat activation dose and declined subsequently without loss of germinability. Germination rates and percentages were considerably greater in tryptone glucose extract (TGE) than in nutrient broth. The addition of 2°° dimethyl sulphoxide did not increase germination in nutrient broth. The spores of var. niger are more resistant to dry‐heat than MD2 although they are less resistant to moist heat. Survivor curves in the dry‐heat range 140°‐170°C gave D‐values from 4–123 to 0.106 min for MD2 and 5.679 to 0.233 min for var. niger recovered on TGE agar. D‐values were lower on poorer media. The z‐values for MD2 and var. niger on TGE were 18.7°C and 21.25d̀C respectively.

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Section: Minutessupporting

confidence: 87%

Thermal Activation and Dry‐heat Inactivation of Spores of Bacillus subtilis MD2 and Bacillus subtilis var. niger

Gurney

Quesnel

1980

Journal of Applied Bacteriology

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“…More importantly, plasmas still provide reactive gases to downstream surfaces for solid or thickened agents that do not evaporate readily. This is of particular importance in the case of biological agents such as anthrax, which would require many days to be neutralized solely by the combination of vacuum and heat at temperatures below 70 C [18]. Hence, this technology has significant advantages over infrared-heated, vacuum-based decon.…”

Section: Evaporation Of Agentmentioning

confidence: 99%

Chemical warfare agent decontamination studies in the plasma decon chamber

Herrmann

Selwyn

Henins

et al. 2002

IEEE Trans. Plasma Sci.

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A "plasma decon chamber" has been developed at Los Alamos National Laboratory (LANL), Albuquerque, NM, to study the decontamination of chemical and biological warfare agents. This technology is targeted at sensitive electronic equipment for which there is currently no acceptable, nondestructive means of decontamination. Chemical reactivity is provided by a downstream flux of reactive radicals such as atomic oxygen and atomic hydrogen, produced in a capacitively coupled plasma. In addition, the decon chamber provides an environment that accelerates the evaporation of chemical agents from contaminated surfaces by vacuum, heat, and forced convection. Once evaporated, agents and agent byproducts are recirculated directly through the plasma, where they undergo further chemical breakdown. Preliminary studies on actual chemical agents were conducted at the U.S. Army Dugway Proving Ground, Dugway, UT. Exposures were conducted at a system pressure of 30 torr, exposure temperature of 70 C, plasma-to-sample standoff distance of 10 cm, and 10% addition of oxygen or hydrogen to a helium balance. This exposure condition was based on optimization studies conducted at LANL on agent simulants. The agents studied were VX and soman (GD) nerve agents and sulfur mustard (HD) blister agent, as well as a thickened simulant. All agents were decontaminated off aluminum substrates to below the detection limit of 0.1% of the initial contamination level of approximately 1 mg/cm 2. For VX, this level of decontamination was achieved in 8-16 min of exposure, while only 2 min were required for the more volatile HD and GD. Evaporation and subsequent gas-phase chemical breakdown in the plasma appears to be the dominant decontamination mechanism for all of the agents. However, an observed difference in the decontamination process between oxygen and hydrogen indicates that chemical reactivity in the liquid phase also plays an important role.

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“…Finally, the fourth barrier is pasteurization or drying of the SCP to produce a final bio-product. 140 Future research must provide evidence that these multiple barriers ensure compliance to feed and safety regulations. Eventually, these evidence must lead to further amendments of current legislation such as the EC Directive 82/471/EEC concerning products used in animal nutrition.…”

Section: Ensuring Product Quality and Safetymentioning

confidence: 99%

“…However, to the authors’ knowledge no similar parameters to produce AHB selectively are available today. Finally, the fourth barrier is pasteurization or drying of the SCP to produce a final bioproduct . Future research must provide evidence that these multiple barriers ensure compliance to feed and safety regulations.…”

Section: Sewage-to-commodities: Challenges Opportunities and Prospectsmentioning

confidence: 99%

Capture–Ferment–Upgrade: A Three-Step Approach for the Valorization of Sewage Organics as Commodities

Alloul

Ganigué

Spiller

et al. 2018

Environ. Sci. Technol.

117

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This critical review outlines a roadmap for the conversion of chemical oxygen demand (COD) contained in sewage to commodities based on three-steps: capture COD as sludge, ferment it to volatile fatty acids (VFA), and upgrade VFA to products. The article analyzes the state-of-the-art of this three-step approach and discusses the bottlenecks and challenges. The potential of this approach is illustrated for the European Union's 28 member states (EU-28) through Monte Carlo simulations. High-rate contact stabilization captures the highest amount of COD (66-86 g COD person equivalent day in 60% of the iterations). Combined with thermal hydrolysis, this would lead to a VFA-yield of 23-44 g COD person equivalent day. Upgrading VFA generated by the EU-28 would allow, in 60% of the simulations, for a yearly production of 0.2-2.0 megatonnes of esters, 0.7-1.4 megatonnes of polyhydroxyalkanoates or 0.6-2.2 megatonnes of microbial protein substituting, respectively, 20-273%, 70-140% or 21-72% of their global counterparts (i.e., petrochemical-based esters, bioplastics or fishmeal). From these flows, we conclude that sewage has a strong potential as biorefinery feedstock, although research is needed to enhance capture, fermentation and upgrading efficiencies. These developments need to be supported by economic/environmental analyses and policies that incentivize a more sustainable management of our resources.

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Inactivation of Bacillus Spores in Dry Systems at Low and High Temperatures

Cited by 12 publications

References 7 publications

Thermal Activation and Dry‐heat Inactivation of Spores of Bacillus subtilis MD2 and Bacillus subtilis var. niger

Thermal Activation and Dry‐heat Inactivation of Spores of Bacillus subtilis MD2 and Bacillus subtilis var. niger

Chemical warfare agent decontamination studies in the plasma decon chamber

Capture–Ferment–Upgrade: A Three-Step Approach for the Valorization of Sewage Organics as Commodities

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