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Main Title: High pressure thermal inactivation of Clostridium botulinum type E endospores – kinetic modeling and mechanistic insights
Author(s): Lenz, Christian A.
Reineke, Kai
Knorr, Dietrich
Vogel, Rudi F.
Type: Article
Language Code: en
Abstract: Cold-tolerant, neurotoxigenic, endospore forming Clostridium (C.) botulinum type E belongs to the non-proteolytic physiological C. botulinum group II, is primarily associated with aquatic environments, and presents a safety risk for seafood. High pressure thermal (HPT) processing exploiting the synergistic effect of pressure and temperature can be used to inactivate bacterial endospores. We investigated the inactivation of C. botulinum type E spores by (near) isothermal HPT treatments at 300–1200 MPa at 30–75°C for 1 s to 10 min. The occurrence of heat and lysozyme susceptible spore fractions after such treatments was determined. The experimental data were modeled to obtain kinetic parameters and represented graphically by isoeffect lines. In contrast to findings for spores of other species and within the range of treatment parameters applied, zones of spore stabilization (lower inactivation than heat treatments alone), large heat susceptible (HPT-induced germinated) or lysozyme-dependently germinable (damaged coat layer) spore fractions were not detected. Inactivation followed first order kinetics. Dipicolinic acid release kinetics allowed for insights into possible inactivation mechanisms suggesting a (poorly effective) physiologic-like (similar to nutrient-induced) germination at ≤450 MPa/≤45°C and non-physiological germination at >500 MPa/>60–70°C. Results of this study support the existence of some commonalities in the HPT inactivation mechanism of C. botulinum type E spores and Bacillus spores although both organisms have significantly different HPT resistance properties. The information presented here contributes to closing the gap in knowledge regarding the HPT inactivation of spore formers relevant to food safety and may help industrial implementation of HPT processing. The markedly lower HPT resistance of C. botulinum type E spores compared with the resistance of spores from other C. botulinum types could allow for the implementation of milder processes without endangering food safety.
Issue Date: 3-Jul-2015
Date Available: 8-Nov-2019
DDC Class: 570 Biowissenschaften; Biologie
660 Chemische Verfahrenstechnik
Subject(s): high pressure thermal processing
HPT processing
pressure-assisted thermal sterilization
bacterial endospores
Clostridium botulinum type E
food safety
inactivation kinetics
kinetic modeling
dipicolinic acid release
Journal Title: Frontiers in Microbiology
Publisher: Frontiers Media S.A.
Publisher Place: Lausanne
Volume: 6
Article Number: 652
Publisher DOI: 10.3389/fmicb.2015.00652
EISSN: 1664-302X
Appears in Collections:FG Lebensmittelbiotechnologie und -prozesstechnik » Publications

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