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COMBASE MODELLING TOOLBOX
Modelling tools integrated in the ComBase browser
For individual ComBase records you have the following options:
- Compare with Prediction – compare individual ComBase data records with worst-case scenarios based on broth-pure culture model predictions (lag or no-lag)
- Fit the Data – fit ComBase data to one of 5 different
model forms and obtain lag time and growth rate
Predictive Tools based on Validated ComBase data
The Modelling Toolbox is a collection of software tools based on ComBase data to predict the growth or inactivation of microrganisms. Currently available predictive tools include two on line applications:
- ComBase Predictor, a set of 23 growth models and 6 thermal death models for predicting the response of many important foodborne pathogenic and spoilage microorganisms to key environmental factors.
- Perfringens Predictor, an application specically for predicting the growth of Clostridium perfringens during the cooling of meats.
The Modelling Toolbox also includes DMFit web-edition, an application to fit log counts vs. time data and extract parameters such as growth/death rate and lag time/shoulder.
To access the programs in the Modelling Toolbox you must first register and then provide your username and password with each login.
Login to ComBase Modelling
Toolbox
ComBase Predictor is a modified, augmented and improved web-version of the Growth Predictor stand-alone program. It isused for predicting the response of pathogens and spoilage microorganisms to key environmental factors (temperature, pH and salt concentration, etc) characterising the food environment. The majority of its models predict the growth/survival of foodborne pathogens as a function of temperature, pH and salt concentration, but in some cases the effect of an additional fourth environmental factor, such as the concentration of carbon dioxide or organic acids is modelled, too.
ComBase Predictor can simultaneously produce predictions for up to four microorganisms. It is also capable of predicting the bacterial response to dynamic temperature environments. This is especially useful when the changes in the storage temperature are known, for example, from a temperature logger. In this case, the data from the temperature logger (up to a hundred time-temperature points) can be entered into an input box.
Predictive models for ComBase Predictor are based only on output from laboratory experiments observed in culture media under well controlled laboratory conditions. Variation of cell concentration is described by a mathematical (growth or survival) curve. Its growth models represent fail-safe, conservative predictions.
Perfringens Predictor is a user friendly tool developed to enable accurate prediction, through simulation, of the response of C. perfringens during the cooling process, for bulked cooked meats. In this web version of Perfringens Predictor, we included new features to the original stand alone version (which is still downloadable from www.ifr.ac.uk/Safety/GrowthPredictor/): the user can now input the pH of the meat and the concentration of salt.
Moreover, predictions can be performed either for cured or uncured products. Both graphical and numerical presentation of the simulated response and the cooling data are provided. Graphs, and data for the simulation profile and cooling curves (in X, Y series), can easily be exported to other programs for the purpose of e.g report writing or comparison.
The program also provides clear interpretation of whether the cooling curve of interest is safe according to predictions and current UK, Food Standards Agency advice.
DMFit web edition is a web-based application to fit bacterial curves where a linear phase is preceded and followed by a stationary phase.
This edition of DMFit allows the user to:- View a graphical representation of microbiological growth/survival data.
- Fit a growth/survival model to the data to obtain parameter estimates for:
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- Maximum growth/death rate
- Lag time (or shoulder)
- Initial cell count
- Final cell count
- Estimate standard errors on these parameters
Other useful programs
Pathogen Modelling Program, a package of models that can be used to predict the growth and inactivation of foodborne pathogens under various environmental conditions.
Seafood Spoilage Predictor, a software for the prediction of the shelf-life and growth of bacteria in different fresh and lightly preserved seafoods e.g. the effect of product temperature profiles recorded over time by data loggers.
Risk Ranger. Risk Ranger is a simple food safety risk calculation tool intended as an aid to determining relative risks from different product, pathogen and processing combinations.
