Chemical States of Bacterial Spores: Heat Resistance and Its Kinetics at Intermediate Water Activity

Alderton, Gordon; Snell, Neva

doi:10.1128/aem.19.4.565-572.1970

Cited by 55 publications

(39 citation statements)

References 7 publications

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“…In fact, they were calculated with the purpose of comparing the Arrhenius and the Bigelow methods. The calculated thermal resistance parameter (z) and E a are in agreement with the range of those values available in literature (Busta 1967;Alderton and Snell 1970;Davies et al 1977;Pflug 1990;Wescott et al 1995). Wescott et al (1995) reported a higher value of E a for B. stearothermophilus spore inactivation than this research, but their trials prevented shoulders in survival curves through prior activation of the spore suspension, applying to it a thermal shock before each heat treatment.…”

Section: Resultssupporting

confidence: 89%

“…Davies et al (1977) reported z-values of 7.3 and 11.8C for spore suspension heated in water and milk, respectively, at a temperature range of 120-160C. Alderton and Snell (1970) reported nonlinear semilogarithimic survivor curves with activation energy (E a ) in the range of 173-193 kJ/mol. Wescott et al (1995) assessed thermal resistance of B. stearothermophilus spores in buffered phosphate solution (pH = 6.8) in batch and continuous processes with E a of 377-405 kJ/ mol.…”

Section: Introductionmentioning

confidence: 99%

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THERMAL DEATH KINETICS OF B. STEAROTHERMOPHILUS SPORES IN SUGARCANE MUST

Nolasco

Massaguer

2007

J Food Process Engineering

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Thermal death kinetic parameters for Bacillus stearothermophilusspores were evaluated in sugarcane must (21.5°Brix, pH = 6.14) at temperatures ranging from 98 to 130C, using the thermal‐death‐time tube method and survivors count. Resulting survival curves showed strong nonlinearity and different shapes according to heating temperature. The 98 and 110C curves showed an initial shoulder or thermal lag and were adjusted to the logistic model. At the temperature range of 120–125C, the two‐term exponential model for population with heterogeneous heat resistance was fitted, and at 130C, the classic linear model was suitable. It was shown that rate constants are influenced by temperature according to two irreconcilable methods: the Arrhenius and the Bigelow methods. Activation energy (Ea) obtained was 249.52 kJ/mol while thermal resistance parameter (z‐value) calculated from Ea and the Bigelow method were 11.48 and 9.19C, respectively. Thermal death kinetic constant, k values, varied from 0.019 to 13.63/min. PRACTICAL APPLICATIONS The thermal degradation kinetics from this work, in conjunction with the appropriate sugar degradation kinetic data (Nolasco Junior 2005, Nolasco Junior and De Massaguer 2006), can be used to properly design an optimal thermal process to inactivate sugarcane must contaminants with optimal sugar content retention. Contaminant control in ethanolic fermentation processes could namely be based on temperature, a physical agent, instead of the current control practice based on antibiotics. Besides, the data from this research meet the more frequently found nonlinear microbial thermal death kinetic model application.

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Section: Resultssupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

THERMAL DEATH KINETICS OF B. STEAROTHERMOPHILUS SPORES IN SUGARCANE MUST

Nolasco

Massaguer

2007

J Food Process Engineering

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“…Because these curves were not linear it was inappropriate to calculate traditional D-values for thermal reduction. Instead, the thermal death rate of ascospores was calculated using the equation (log 10 N 0 Ϫ log 10 N) ␣ ϭ (k) t + C (Alderton and Snell, 1970;King et al, 1979;King and Halbrook, 1987). N 0 and N are the initial count and the remaining survivors of ascospores/mL and t is the heating time (min) at a given temperature.…”

Section: Calculation Of Thermal Death Rate Of Ascosporesmentioning

confidence: 99%

Heat resistance of Byssochlamys nivea, Byssochlamys fulva and Neosartorya fischeri isolated from canned tomato paste

Kotzekidou

1997

Journal of Food Science

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Cultures of heat resistant molds (20) were isolated from spoiled canned tomato paste in order to estimate the pasteurization efficiency applied to commercially canned products. Ascospores of nine strains grown on malt extract agar for 30 days at 30ЊC, survived heating at 85ЊC for 20 min when initial numbers were near 10 5 /mL. Of these heat resistant strains were identified: two Byssochlamys nivea, three Byssochlamys fulva and four Neosartorya fischeri strains. Ascospores of all cultures were more heat resistant in tomato juice than in phosphate buffer. Thermal death rate curves were nonlogarithmic but approached logarithmic death rates at higher temperatures. The thermal destruction time for 1 log 10 at 90ЊC was 1.5 min for a Byssochlamys nivea strain, 8.1 min for a Byssochlamys fulva strain and 4.4 to 6.6 min for Neosartorya fischeri strains.

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“…Amongst the external factors, pH value greatly affects the heat resistance (Weiss, 1921;Levine & Fellers, 1940;Sognefest et al, 1948;Walker, 1964;Cotterill, 1968;Garibaldi, 1968;Garibaldi et al, 1969). The same is true for the a, value (Murrell & Scott, 1966;Fox & Eder, 1969;Cotterill & Glauert, 1969;Alderton & Snell, 1970;Vrchlabsky & Leistner, 1970). I n addition, the chemical character of the solutes determining a given a, exerts a profound influence on heat resistance (Baird-Parker et aE., 1970;Goepfert et al, 1970).…”

Section: (C) Processing Factors (I) Heatmentioning

confidence: 73%

Physiological and Metabolic Attributes of Microbial Groups Associated with Foods

Mossel

1971

Journal of Applied Bacteriology

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Chemical States of Bacterial Spores: Heat Resistance and Its Kinetics at Intermediate Water Activity

Cited by 55 publications

References 7 publications

THERMAL DEATH KINETICS OF B. STEAROTHERMOPHILUS SPORES IN SUGARCANE MUST

THERMAL DEATH KINETICS OF B. STEAROTHERMOPHILUS SPORES IN SUGARCANE MUST

Heat resistance of Byssochlamys nivea, Byssochlamys fulva and Neosartorya fischeri isolated from canned tomato paste

Physiological and Metabolic Attributes of Microbial Groups Associated with Foods

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