title: Estimating the survival of Clostridium botulinum spores during heat treatments.
abstract: A recently published study of the inactivation of Clostridium botulinum spores at various temperatures in the range of 101 to 121 degrees C and neutral pH revealed that their semilogarithmic survival curves all had considerable upward concavity. This finding indicated that heat inactivation of the spores under these conditions did not follow a first-order kinetics and that meaningful D values could not be calculated. The individual survival curves could be described by the cumulative form of the Weibull distribution, i.e., by log S = -b(T)t(n(T)), where S is the survival ratio and b(T) and n(T) are temperature-dependent coefficients. The fact that at all temperatures in the above range n(T) was smaller than 1 suggested that as time increases sensitive members of the population parish and survivors with increasing resistance remain. If damage accumulation is not a main factor, and the inactivation is path independent, then survival curves under monotonously increasing temperature can be constructed using a relatively simple model, which can be used to calculate the spores' survival in a limiting case. This is demonstrated with computer-simulated heating curves and the experimental constants of the C. botulinum spores, setting the number of decades reduction to 8, 10, and 12 (the current criterion for commercial sterility).
authors.affiliation: Department of Food Science, University of Massachusetts, Amherst 01003, USA. micha.peleg@foodsci.umass.edu
authors.forename: M
authors.initials: M
authors.lastname: Peleg
authors.forename: M B
authors.initials: MB
authors.lastname: Cole
mesh_terms: D003014:Clostridium botulinum / Q000502:physiology*; D003198:Computer Simulation; D006358:Hot Temperature; D013171:Spores, Bacterial / Q000502:physiology