Kinetic evaluation of physiological heterogeneity in bacterial spores during thermal inactivation

Xu, Hua; He, Xinlong; Gou, Jingyu; Lee, Hyeon-Yong; Ahn, Juhee

doi:10.2323/jgam.55.295

Cited by 8 publications

(11 citation statements)

References 22 publications

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“…Little data are available on the inactivation kinetics of B. amyloliquefaciens , and most of the studies determined only the D ‐value (Ahn et al. 2007; Xu et al. 2009).…”

Section: Resultsmentioning

confidence: 99%

Thermal resistance of aerobic spore formers isolated from food products

Witthuhn¹,

Lücking²,

Atamer³

et al. 2011

International Journal of Dairy Technology

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“…Little data are available on the inactivation kinetics of B. amyloliquefaciens , and most of the studies determined only the D ‐value (Ahn et al. 2007; Xu et al. 2009).…”

Section: Resultsmentioning

confidence: 99%

Thermal resistance of aerobic spore formers isolated from food products

Witthuhn¹,

Lücking²,

Atamer³

et al. 2011

International Journal of Dairy Technology

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“…Heat may also inactivate or injure spores (Xu et al . ) and heterogeneous responses to heat increase the difficulty in ensuring spore inactivation for prevention of disease transmission.…”

Section: Introductionmentioning

confidence: 99%

Impacts of sporulation temperature, exposure to compost matrix and temperature on survival of Bacillus cereus spores during livestock mortality composting

et al. 2015

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“…High spore wet heat resistance is acquired late in sporulation, largely in parallel with the uptake of DPA by the developing forespore and the final decrease in spore core water content. However, the precise time of acquisition of full spore heat resistance during sporulation is not completely clear because (i) precise measurements of wet heat resistance are usually carried out only on purified spores; (ii) analysis of acquisition of wet heat resistance can be carried out only with spore populations, and the lack of precise synchrony in sporulation of cell populations can complicate kinetic analysis of events in sporulation; and (iii) the specific conditions in sporulating cultures, including the composition of the medium and the environment in the mother cell surrounding the developing spore, may change during sporulation, and such changes could modify spore wet heat resistance compared to that of purified spores in water.It is also clear that the wet heat resistance of individuals in spore populations can vary significantly (1,3,9,13,19,27,34,36). Indeed, analyses of spore killing by wet heat as a function of time often suggest that there is a significant level of more wet-heat-resistant spores in populations (27).…”

mentioning

confidence: 99%

“…It is also clear that the wet heat resistance of individuals in spore populations can vary significantly (1,3,9,13,19,27,34,36). Indeed, analyses of spore killing by wet heat as a function of time often suggest that there is a significant level of more wet-heat-resistant spores in populations (27).…”

mentioning

confidence: 99%

Maturation of Released Spores Is Necessary for Acquisition of Full Spore Heat Resistance during Bacillus subtilis Sporulation

Sánchez-Salas

Setlow

Zhang

et al. 2011

Appl Environ Microbiol

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The first ϳ10% of spores released from sporangia (early spores) during Bacillus subtilis sporulation were isolated, and their properties were compared to those of the total spores produced from the same culture. The early spores had significantly lower resistance to wet heat and hypochlorite than the total spores but identical resistance to dry heat and UV radiation. Early and total spores also had the same levels of core water, dipicolinic acid, and Ca and germinated similarly with several nutrient germinants. The wet heat resistance of the early spores could be increased to that of total spores if early spores were incubated in conditioned sporulation medium for ϳ24 h at 37°C (maturation), and some hypochlorite resistance was also restored. The maturation of early spores took place in pH 8 buffer with Ca 2؉ but was blocked by EDTA; maturation was also seen with early spores of strains lacking the CotE protein or the coat-associated transglutaminase, both of which are needed for normal coat structure. Nonetheless, it appears to be most likely that it is changes in coat structure that are responsible for the increased resistance to wet heat and hypochlorite upon early spore maturation.Spores of Bacillus and Clostridium species are dormant and extremely resistant to a variety of agents, including high temperatures, radiation, and many chemicals (19,31). This extreme spore resistance has major applied implications, because spores of Bacillus and Clostridium species are vectors for food spoilage and a number of diseases, some of which are food borne. As a consequence, there is much interest in the mechanisms of spore resistance as well as methods for spore inactivation.The most commonly used method for spore inactivation is wet heat treatment, which is extremely effective, even though spores are generally resistant to temperatures ϳ40°C higher than their growing-cell counterparts (4,19,31). Factors involved in spores' extreme resistance to wet heat include (i) the protection of spore DNA by its saturation with the ␣/␤-type small, acid-soluble spore proteins (SASPs); (ii) the thick proteinaceous spore coat layer; (iii) the thick layer of cortex peptidoglycan surrounding the spore core; (iv) the high level of pyridine-2,6-dicarboxylic acid (dipicolinic acid [DPA]) and its associated divalent cations, mostly Ca 2ϩ , in the spore core; and, most importantly, (v) the low water content of the core of spores suspended in water (4,5,19,31,32). High spore wet heat resistance is acquired late in sporulation, largely in parallel with the uptake of DPA by the developing forespore and the final decrease in spore core water content. However, the precise time of acquisition of full spore heat resistance during sporulation is not completely clear because (i) precise measurements of wet heat resistance are usually carried out only on purified spores; (ii) analysis of acquisition of wet heat resistance can be carried out only with spore populations, and the lack of precise synchrony in sporulation of cell populations can complicate ...

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Kinetic evaluation of physiological heterogeneity in bacterial spores during thermal inactivation

Cited by 8 publications

References 22 publications

Thermal resistance of aerobic spore formers isolated from food products

Thermal resistance of aerobic spore formers isolated from food products

Impacts of sporulation temperature, exposure to compost matrix and temperature on survival of Bacillus cereus spores during livestock mortality composting

Maturation of Released Spores Is Necessary for Acquisition of Full Spore Heat Resistance during Bacillus subtilis Sporulation

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