A meta-analysis accounting for sources of variability to estimate heat resistance reference parameters of bacteria using hierarchical Bayesian modeling: Estimation of D at 121.1 degrees C and pH 7, z(T) and z(pH) of Geobacillus stearothermophilus
Résumé
Predicting microbial survival requires reference parameters for each micro-organism of concern. When data are abundant and publicly available, a meta-analysis is a useful approach for assessment of these parameters, which can be performed with hierarchical Bayesian modeling. Geobacillus stearothermophilus is a major agent of microbial spoilage of canned foods and is therefore a persistent problem in the food industry. The thermal inactivation parameters of G. stearothermophilus (D-ref, i.e.the decimal reduction time D at the reference temperature 121.1 degrees C and pH 7.0, z(T) and z(pH)) were estimated from a large set of 430 D values mainly collected from scientific literature. Between-study variability hypotheses on the inactivation parameters D-ref, z(T) and z(pH) were explored, using three different hierarchical Bayesian models. Parameter estimations were made using Bayesian inference and the models were compared with a graphical and a Bayesian criterion. Results show the necessity to account for random effects associated with between-study variability. Assuming variability on D-ref, z(T) and z(pH), the resulting distributions for D-ref, z(T) and z(pH) led to a mean of 3.3 min for D-ref (95% Credible Interval CI = [0.8; 9.6]), to a mean of 9.1 degrees C for z(T) (CI = [5.4; 13.1]) and to a mean of 4.3 pH units for z(pH) (CI = [2.9; 63]), in the range pH 3 to pH 7.5. Results are also given separating variability and uncertainty in these distributions, as well as adjusted parametric distributions to facilitate further use of these results in aqueous canned foods such as canned vegetables. (c) 2012 Elsevier B.V. All rights reserved.
Mots clés
THERMAL-RESISTANCE
BACILLUS-STEAROTHERMOPHILUS
COLD-SMOKED SALMON
HIGH-TEMPERATURES
KINETIC-PARAMETERS
LISTERIA-MONOCYTOGENES
Meta-analysis
Hierarchical Bayesian models
Variability
Geobacillus stearothermophilus
Thermal inactivation parameters
Canning
QUANTITATIVE RISK-ASSESSMENT
PREDICTIVE MODEL
SPORES
INACTIVATION