Open AccessSynergistic Inactivation of Spores of ProteolyticClostridium botulinumStrains by High Pressure and Heat Is Strain and Product Dependent
Author(s) -
Michelle Bull,
Sandra Olivier,
R. J. van Diepenbeek,
F.J.M. Kormelink,
Brian Chapman
Publication year - 2009
Publication title -
applied and environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.552
H-Index - 324
eISSN - 1070-6291
pISSN - 0099-2240
DOI - 10.1128/aem.01426-08
Subject(s) - clostridium sporogenes , clostridium botulinum , spore , strain (injury) , sterilization (economics) , food science , clostridium , clostridiaceae , high pressure , heat resistance , chemistry , microbiology and biotechnology , bacteria , biology , materials science , toxin , genetics , anatomy , engineering physics , composite material , monetary economics , economics , foreign exchange market , engineering , foreign exchange
The combined high pressure and heat resistances of spores of five proteolyticClostridium botulinum strains and of the nonpathogenic surrogate strainClostridium sporogenes PA3679 were compared with their heat-only resistances on the basis of equivalent accumulated thermal lethality, expressed as equivalent minutes at a reference temperature of 105°C (F 105 ° C ). Comparisons were made with three model (i.e., diluted) products, namely, 30% (wt/wt) Bolognese sauce, 50% (wt/wt) cream sauce, and rice water agar. Pressure was determined to act synergistically with heat during high-pressure thermal (HPT) processing forC. botulinum FRRB 2802 (NCTC 7273) andC. botulinum FRRB 2804 (NCTC 3805 and 62A) in the Bolognese and cream sauces and forC. botulinum FRRB 2807 (213B) in the Bolognese sauce only. No synergy was observed forC. botulinum FRRB 2803 (NCTC 2916) or FRRB 2806 (62A) orC. sporogenes FRRB 2790 (NCTC 8594 and PA3679) in any of the model products. No significant protective effect of pressure against spore inactivation was determined for anyClostridium strain in any product. Because synergy was not consistently observed among strains ofC. botulinum or among products, the prediction of inactivation ofC. botulinum spores by HPT sterilization (HPTS) for the present must assume a complete lack of synergy. Therefore, any HPTS process for low-acid shelf-stable foods must be at least thermally equivalent to an F0 process of 2.8 min, in line with current good manufacturing practices. The results of this study suggest that the use ofC. sporogenes PA3679 as a surrogate organism may risk overestimating inactivation ofC. botulinum by HPT processing.