Initiation of Germination and Inactivation of
            <i>Bacillus pumilus</i>
            Spores by Hydrostatic Pressure

Clouston, J. G.; Wills, P.A.

doi:10.1128/jb.97.2.684-690.1969

Cited by 121 publications

(37 citation statements)

References 13 publications

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“…While the vegetative forms of micro-organisms in food are generally inactivated by pressures in the range of 600-800 MPa, spores proved to be far more tolerant. However, in the 1960s, it was found that relatively low pressures, even as low as 100 MPa, or even less for some spores, could cause their germination (Clouston and Wills 1969;Gould and Sale 1970). This introduced the possibility of preserving food by mild pressurization followed by a mild heat treatment to inactivate the, now heat-sensitive, pressure-germinated spores.…”

Section: Inactivation By High Hydrostatic Pressurementioning

confidence: 99%

History of science – spores.

Gould

2006

J Appl Microbiol

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Bacterial endospores were first studied 130 years ago by Cohn in 1876 and independently by Koch in the same year. Although spore dormancy and resistance have been much studied since then, questions still remain concerning the basic mechanisms and the kinetics of heat inactivation in particular. Likewise, the extreme dormancy and longevity of spores was recognized early on and later greatly extended but still evade complete understanding. Evidence has accumulated for the involvement of specific spore components such as calcium, dipicolinic acid, small acid soluble proteins in the core and peptidoglycan in the cortex. Involvement of physical factors too, such as the relative dehydration of the core, maybe in a high‐viscosity state or even in a glassy state, has added to appreciation of the multicomponent nature of dormancy and resistance. Spore‐former morphology formed the basis for early classification systems of sporeformers from about 1880 and consolidated in the mid‐1900s, well prior to the use of modern genetic procedures. With respect to sporulation, groundbreaking sequence studies in the 1950s provided the basis for later elucidation of the genetic control widely relevant to many cell differentiation mechanisms. With respect to the breaking of dormancy (activation and germination), the elucidation of mechanisms began in the 1940s following the observations of Hills at Porton who identified specific amino acid and riboside ‘germinants’, and laid the basis for the later genetic analyses, the identification of germinant receptor genes and the elucidation of key germination reactions. The nonexponential nature of germination kinetics has thwarted the development of practical Tyndallization‐like processing. So inactivation by heat remains the premier method of spore control, the basis of a huge worldwide industry, and still relying on the basic kinetics of inactivation of Clostridium botulinum spores, and the reasoning regarding safety first evolved by Bigelow et al. in 1920 and Esty and Meyer in 1922. ‘Newer’ processes such as treatment with ionizing radiation (first proposed in 1905) and high hydrostatic pressure (first proposed in 1899) may be introduced if consumer resistance and some remaining technical barriers could be overcome.

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Section: Inactivation By High Hydrostatic Pressurementioning

confidence: 99%

History of science – spores.

Gould

2006

J Appl Microbiol

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“…Use of high pressure (HP) as a method for the inactivation of spores in foods has been widely explored since the late 1960s. Clouston and Wills (1969) were the first to recognize the potential of HP for spore inactivation, by identifying the fact that HP initiates germination of Summary Aims: The aim of this work was to investigate the germination and inactivation of spores of Bacillus species in buffer and milk subjected to high pressure (HP) and nisin. Methods and Results: Spores of Bacillus subtilis and Bacillus cereus suspended in milk or buffer were treated at 100 or 500 MPa at 40°C with or without 500 IU ml )1 of nisin.…”

Section: Introductionmentioning

confidence: 99%

The combined effects of high pressure and nisin on germination and inactivation ofBacillusspores in milk

Black

Linton

McCall

et al. 2008

Journal of Applied Microbiology

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Summary Aims: The aim of this work was to investigate the germination and inactivation of spores of Bacillus species in buffer and milk subjected to high pressure (HP) and nisin. Methods and Results: Spores of Bacillus subtilis and Bacillus cereus suspended in milk or buffer were treated at 100 or 500 MPa at 40°C with or without 500 IU ml−1 of nisin. Treatment at 500 MPa resulted in high levels of germination (4 log units) of B. subtilis spores in both milk and buffer; this increased to >6 logs by applying a second cycle of pressure. Viability of B. subtilis spores in milk and buffer was reduced by 2·5 logs by cycled HP, while the addition of nisin (500 IU ml−1) prior to HP treatment resulted in log reductions of 5·7 and 5·9 in phosphate buffered saline and milk, respectively. Physical damage of spores of B. subtilis following HP was apparent using scanning electron microscopy. Treating four strains of B. cereus at 500 MPa for 5 min twice at 40°C in the presence of 500 IU ml−1 nisin proved less effective at inactivating the spores of these isolates compared with B. subtilis and some strain‐to‐strain variability was observed. Conclusions: Although high levels of germination of Bacillus spores could be achieved by combining HP and nisin, complete inactivation was not achieved using the aforementioned treatments. Significance and Impact of the Study: Combinations of HP treatment and nisin may be an appealing alternative to heat pasteurization of milk.

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“…On the other hand, it has already been shown that bacterial spores can be germinated by ''low'' pressures of about 200-400 MPa. After germination, the vegetative cells can be inactivated by pressure (Clouston and Wills, 1969;Gould and Sale, 1970). The pressure resistance of yeasts and moulds is slightly lower than that of non-sporulated bacteria (Hashizume et al, 1995;Ogawa et al, 1990;Pandya et al, 1995).…”

Section: Introductionmentioning

confidence: 99%

Kinetics of combined pressure-temperature inactivation of avocado polyphenoloxidase

Weemaes

Ludikhuyze

Broeck

et al. 1998

Biotechnol. Bioeng.

118

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Irreversible combined pressure‐temperature inactivation of the food quality related enzyme polyphenoloxidase was investigated. Inactivation rate constants (k) were obtained for about one hundred combinations of constant pressure (0.1–900 MPa) and temperature (25–77.5°C). According to the Eyring and Arrhenius equation, activation volumes and activation energies, respectively, representing pressure and temperature dependence of the inactivation rate constant, were calculated for all temperatures and pressures studied. In this way, temperature and pressure dependence of activation volume and activation energy, respectively, could be considered. Moreover, for the first time, a mathematical model describing the inactivation rate constant of a food quality‐related enzyme as a function of pressure and temperature is formulated. Such pressure‐temperature inactivation models for food quality‐related aspects (e.g., the spoilage enzyme polyphenoloxidase) form the engineering basis for design, evaluation, and optimization of new preservation processes based on the combined effect of temperature and pressure. Furthermore, the generated methodology can be used to develop analogous kinetic models for microbiological aspects, which are needed from a safety and legislative point of view, and other quality aspects, e.g., nutritional factors, with a view of optimal quality and consumer acceptance. © 1998 John Wiley & Sons, Inc. Biotechnol Bioeng 60: 292–300, 1998.

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Initiation of Germination and Inactivation of Bacillus pumilus Spores by Hydrostatic Pressure

Cited by 121 publications

References 13 publications

History of science – spores.

History of science – spores.

The combined effects of high pressure and nisin on germination and inactivation ofBacillusspores in milk

Kinetics of combined pressure-temperature inactivation of avocado polyphenoloxidase

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