Help
View models
Here you find some general information + references on the five models on which CRAF is based.
Compare modules
With the "compare modules" feature you can look up the details for the different modules for each of the risk assessments, and compare them.
First, you can select a module, that is a stage in the farm to fork food chain.
Second, you can tick the model you want information on, or the ones you would like to compare.
The next screen then gives you information on:
Input and output
In CRAF input and output are defined as the prevalences and/or concentrations of Campylobacter that enter the processing stage (input) and leave the processing stage (output).
The tables show how the prevalences and concentrations are defined: the unit of prevalence and concentration (vertical) and whether the model uses them as a point estimate or a distribution; and if it is a distribution wether this distribution describes variability, uncertainty or both.
By clicking on a specific prevalence or concentration, more details can be obtained.
Equation parameters
In CRAF these are all parameters and variables applied in the model that are not input and output as defined above.
By clicking on an equation parameter, more details can be obtained.
Equation
A formal description of the model, identifying how the equation parameters are used, and how they link to the input and output.
References
Where to obtain all published details on the models.
Compose chain
With the "select chain" feature you can select different models that you propose to use for different modules in the farm to fork chain. As a result you will get an overview of inputs and outputs of these different modules. Yopu can use this overview to check how well outputs form one model overlap with the input of the next stage. If not, you will need to consider how feasible it is to link the modules in one food chain model, and reformulate the models to obtain a good, new food chain QMRA model.
Parameter details
For inputs, outputs and equation parameters, CRAF contains the following information:
| parameter symbol | symbol used for the parameter |
| parameter name | name of the parameter |
| parameter unit | unit of the parameter |
| sub parameter symbol | a parameter may use subparameters to characterize the distribution that the parameter describes (e.g. by mean. standard deviation or percentile); this is the symbol used for this subparameter |
| value | The (default) value of the (sub-)parameter in the model. In principle this is a number, but it may be a distribution as well |
| value unit | the unit of the value given |
| value_type | further explanation of the value: what does it represent |
| sample_measure | if value is based on data, give the sample measure (e.g 10 g neck skin) |
| further explanation | further explanation |
| class unit | To further explain what the uncertainty/variability distribution describes |
| based on data, model or expert opinion | what is the value based on |
| product_state | if relevant: is this about living animals, fresh product or frozen product or both |
Documents
- CRAF final report
- Data catalogue
- A comparison of risk assessments on Campylobacter in broiler meat
Nauta et al., 2009. International Journal of Food Microbiology, vol 129, issue 2
