Title: Inactivation of Bacillus cereus spores in milk by mild pressure and heat treatments
Authors: Van Opstal, Isabelle ×
Bagamboula, CF
Vanmuysen, SCM
Wuytack, EY
Michiels, Christiaan #
Issue Date: 2004
Series Title: International journal of food microbiology vol:92 issue:2 pages:227-234
Conference: date:Katholieke Univ Leuven, Food Microbiol Lab, B-3001 Louvain, Belgium
Abstract: The objective of this work was to study the germination and subsequent inactivation of Bacillus cereus spores in milk by mild hydrostatic pressure treatment. In an introductory experiment with strain LMG6910 treated at 40degreesC for 30 min at 0, 100, 300 and 600 MPa, germination levels were 1.5 to 3 logs higher in milk than in 100 mM potassium phosphate buffer (pH 6.7). The effects of pressure and germination-inducing components present in the milk on spore germination were synergistic. More detailed experiments were conducted in milk at a range of pressures between 100 and 600 MPa at temperatures between 30 and 60 degreesC to identify treatments that allow a 6 log inactivation of B. cereus spores. The mildest treatment resulting in a 6 log germination was 30 min at 200 MPa/40 degreesC. Lower treatment pressures or temperatures resulted in considerably less germination, and higher pressures and temperatures further increased germination, but a small fraction of spores always remained ungerminated. Further, not all germinated spores were inactivated by the pressure treatment, even under the most severe conditions (600 MPa/60 degreesC). Two possible approaches to achieve a 6 log spore inactivation were identified, and validated in three additional B. cereus strains. The first is a single step treatment at 500 MPa/60 degreesC for 30 min, the second is a two-step treatment consisting of pressure treatment for 30 min at 200 MPa/45 degreesC to induce spore germination, followed by mild heat treatment at 60 degreesC for 10 min to kill the germinated spores. Reduction of the pressurization time to 15 min still allows a 5 log inactivation. These results illustrate the potential of high-pressure treatment to inactivate bacterial spores in minimally processed foods. (C) 2003 Elsevier B.V. All rights reserved.
ISSN: 0168-1605
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Centre for Food and Microbial Technology
× corresponding author
# (joint) last author

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