Comparison of Survivor Curves of Bacillus subtilis Spores Subjected to Wet and Dry Heat

Fox, Kenneth; Eder, Bruce D.

doi:10.1111/j.1365-2621.1969.tb12075.x

Cited by 37 publications

(22 citation statements)

References 18 publications

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“…In fact, experiments on brief heating to more than 100°C of typical samples of MS-2 coliphage spores and Bacilus subtilis bacteria placed in vacuum on the back side of a thin metal biologically neutral target illuminated by a laser beam showed that they can survive these and even higher temperatures (Adushkin, 2005). In accordance with the data of other analogous investigations (Fox and Eder, 1969;Nicholson et al, 2000), it has been inferred that the probability of bacterium survival, which turned out to be weakly dependent on the duration and regime of heating, sharply drops at temperatures above ~200°ë and becomes critical (at a level of ~10 -4 ) at maximal values of ~250°ë. These experiments can be brought into correlation with the heating regimes of particles smaller than 10 µm in diameter entering the Earth's atmosphere.…”

Section: Collisions Of Dust Particles With Terrestrial Planetssupporting

confidence: 87%

Migration of Dust Particles and Delivery of Volatiles to the Terrestrial Planets

Marov¹,

Ипатов²

2005

Sol Syst Res

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Results of computer simulations of the migration of small bodies and dust in the Solar System showed that a relative fraction of cometary and trans-Neptunian dust particles in the total balance of the dust encountering the terrestrial planets can be significant. The contribution of dust particles to the delivery of volatiles to the terrestrial planets is estimated to be 3-4 orders of magnitude less than that of small bodies. However, the dust particles could be most efficient in the delivery of organic or even biogenic matter to the Earth, because they experience substantially weaker heating when passing through the atmosphere.

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Section: Collisions Of Dust Particles With Terrestrial Planetssupporting

confidence: 87%

Migration of Dust Particles and Delivery of Volatiles to the Terrestrial Planets

Marov¹,

Ипатов²

2005

Sol Syst Res

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“…The mechanisms whereby wet heat inactivates spores more than dry heat have not been fully characterized, although it is not through DNA damage (22). It has been reported that the number of viable B. subtilis spores declined by more than 99% after 2 days of exposure to wet heat at 77°C (6). In addition, it has been shown, that vegetative Bacillus organisms are even more sensitive to wet heat, being inactivated at temperatures that are 30 to 40°C lower than those for spores (8).…”

Section: Discussionmentioning

confidence: 99%

Viability of Bacillus licheniformis and Bacillus thuringiensis Spores as a Model for Predicting the Fate of Bacillus anthracis Spores during Composting of Dead Livestock

Reuter

Alexander

McAllister

2011

Appl Environ Microbiol

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Safe disposal of dead livestock and contaminated manure is essential for the effective control of infectious disease outbreaks. Composting has been shown to be an effective method of disposal, but no information exists on its ability to contain diseases caused by spore-forming bacteria, such as Bacillus anthracis. Duplicate composters (east and west), each containing 16 dead cattle, were constructed (final capacity, 85,000 kg). Spores (10 7 CFU/g manure) of Bacillus licheniformis and Bacillus thuringiensis were mixed with autoclaved feedlot manure and placed in either sterile vials or porous nylon bags. Compost temperatures in the west composter were slightly higher than in the east composter. Viable B. thuringiensis spores were reduced to <10 2 CFU in all samples after 112 days but were isolated from bags (west composter) at <10 2 and at 10 5 CFU (east composter) after 230 days. In contrast, B. licheniformis was at <10 2 CFU in vials (west composter) after 112 days but remained at 10 6 CFU after 230 days (east composter). Similarly, B. licheniformis in bags was not detected after 230 days in the west composter but remained at 10 7 CFU in the east composter. Our study suggests that spore viability was reduced in the west composter by exposure to compost and elevated temperatures over time. Different temperature profiles may explain why spores remained viable in the east structure but were largely rendered nonviable in the west structure. Under practical conditions, variation in composting microclimates may preclude the complete inactivation of Bacillus spores, including those of B. anthracis, during composting. However, composting may still have merit as a method of biocontainment, reducing and diluting the transfer of infectious spores into the environment.

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“…The shape of all survival curves of bacterial spores exposed to IRH treatment was an upward convex, whereas concave survival curves have often been obtained by dry heat sterilization (Fox and Pflug, 1968;Fox and Eder, 1969;Murrell and Scott, 1966). Appearance of these nonlinear parts in the survival curve often leads to a misestimation of the total treatment time required for spore inactivation, because the simple logarithmic curve has been traditionally applied to the prediction of survival.…”

Section: Microorganismsmentioning

confidence: 99%

Inactivation Effect of Infrared Radiation Heating on Bacterial Spores Pretreated at Various Water Activities

Hamanaka¹,

Uchino

Furuse³

et al. 2005

Biocontrol Sci.

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Bacillus subtilis spores pretreated at various water activities (aw, from 0.005 to 0.996) were inactivated by infrared radiation heating (IRH) at 0.5 and 1.0 kW of electric power under dry conditions in an open system. The resistance of B. subtiiis spores to IRH was greater in the range of 0.25 to 0.874 aw, and had the maximum value when aw was 0.796 at 0.5 kW and 0.688 at 1.0 kW. Markedly lower IRH resistance of B. subtilis spores was observed at the lower or higher levels of aw.

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Comparison of Survivor Curves of Bacillus subtilis Spores Subjected to Wet and Dry Heat

Cited by 37 publications

References 18 publications

Migration of Dust Particles and Delivery of Volatiles to the Terrestrial Planets

Migration of Dust Particles and Delivery of Volatiles to the Terrestrial Planets

Viability of Bacillus licheniformis and Bacillus thuringiensis Spores as a Model for Predicting the Fate of Bacillus anthracis Spores during Composting of Dead Livestock

Inactivation Effect of Infrared Radiation Heating on Bacterial Spores Pretreated at Various Water Activities

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