This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Margosch, D. Articles by Gänzle, M. G. Search for Related Content PubMed PubMed Citation Articles by Margosch, D. Articles by Gänzle, M. G. Agricola Articles by Margosch, D. Articles by Gänzle, M. G.

High-Pressure-Mediated Survival of Clostridium botulinum and Bacillus amyloliquefaciens Endospores at High Temperature

Dirk Margosch,¹ Matthias A. Ehrmann,¹ Roman Buckow,² Volker Heinz,² Rudi F. Vogel,^1* and Michael G. Gänzle^1,

Technische Universität München, Lehrstuhl Technische Mikrobiologie, Weihenstephaner Steig 16, D-85350 Freising,¹ Technische Universität Berlin, Königin Luise-Strasse, Berlin, Germany²

Received 12 July 2005/ Accepted 27 February 2006

Endospores of proteolytic type B Clostridium botulinum TMW 2.357 and Bacillus amyloliquefaciens TMW 2.479 are currently described as the most high-pressure-resistant bacterial spores relevant to food intoxication and spoilage in combined pressure-temperature applications. The effects of combined pressure (0.1 to 1,400 MPa) and temperature (70 to 120°C) treatments were determined for these spores. A process employing isothermal holding times was established to distinguish pressure from temperature effects. An increase in pressure (600 to 1,400 MPa) and an increase in temperature (90 to 110°C) accelerated the inactivation of C. botulinum spores. However, incubation at 100°C, 110°C, or 120°C with ambient pressure resulted in faster spore reduction than treatment with 600 or 800 MPa at the same temperature. This pressure-mediated spore protection was also observed at 120°C and 800, 1,000, or 1,200 MPa with the more heat-tolerant B. amyloliquefaciens TMW 2.479 spores. Inactivation curves for both strains showed a pronounced pressure-dependent tailing, which indicates that a small fraction of the spore populations survives conditions of up to 120°C and 1.4 GPa in isothermal treatments. Because of this tailing and the fact that pressure-temperature combinations stabilizing bacterial endospores vary from strain to strain, food safety must be ensured in case-by-case studies demonstrating inactivation or nongrowth of C. botulinum with realistic contamination rates in the respective pressurized food and equipment.

Present address: University of Alberta, Edmonton, Alberta, Canada.