Analysis of the Influence of Environmental Parameters on Clostridium botulinum Time-to-Toxicity by Using Three Modeling Approaches

Abstract

This study used the technique of waiting time modeling to analyze the combined effects of temperature, pH, carbohydrate, protein, and lipid on the time-to-toxicity of Clostridium botulinum 56A. Waiting time models can be used whenever the time to the occurrence of some event is the variable of interest. In the case of the time-to-toxicity data, the variable is the time from the beginning of an experiment until a tube is identified as positive. The statistical analysis used the SAS procedure LIFEREG and included determination of the form of the response surface, identification of the error distribution, and simplification of the response surface. We found that increasing the macromolecule concentration decreased the probability of toxin formation. The probability of toxin formation also decreased at lower temperatures and at pHs further from the optimum. The waiting time modeling approach to developing models for botulinal toxin formation compared favorably with other approaches but had one specific advantage. Waiting time models have the inherent advantage that safety concerns regarding predictions are automatically quantified in the analysis by formally identifying a distribution of times-to-toxicity. The use of this time-to-toxicity distribution permits a customizable margin of safety (e.g., one in a million) not possible with other approaches.

Growth and growth boundary model with terms for melting salts to predict growth responses of Listeria monocytogenes in spreadable processed cheese

“…A longer open shelf-life or larger safety margin may be desirable and the new model predicts that by substituting the orthophosphate with 2.0 % tri-phosphate the reformulated product requires 13-17 days at 8°C to reach the same critical concentration for L. monocytogenes. It seems interesting to apply the new model in combination with available models to predict growth or toxin formation by C. botulinum in spreadable process cheese containing melting salts (Glass et al, 2017;Schaffner et al, 1998;ter Steeg and Cuppers, 1995b) to formulate recipes that will inhibit growth of the relevant pathogens.…”

“…The approach used in the present study to develop an extensive model including the inhibiting effect of both organic acids and phosphate salts could also be interesting for C. botulinum as available predictive models with relevance for spreadable processed cheese include few environmental parameters (Glass et al, 2017;Schaffner et al, 1998;ter Steeg and Cuppers, 1995b).…”

Application of superabsorbent polymers (SAP) as desiccants to dry maize and reduce aflatoxin contamination

“…3. The increase in total aflatoxin contamination over time can roughly be approximated by the following logistic equation (Brzonkalik et al 2011;Schaffner et al 1998):…”

Use of Modeling to Enhance the Microbiological Safety of the Food System

“…Intoxication requires that the microorganism produce a toxin in the food product. Many microbial models predict time‐to‐toxicity or predict the population level necessary for toxin production by toxigenic pathogens (Schaffner and others 1998; Whiting and Golden 2002). The foodborne pathogens responsible for production of toxins in foods include Clostridium botulinum , Staphylococcus aureus , and Bacillus cereus.…”