NUSAP Method for Evaluating the Data Quality in a Quantitative Microbial Risk Assessment Model for Salmonella in the Pork Production Chain

The numeral unit spread assessment pedigree (NUSAP) system was implemented to evaluate
the quality of input parameters in a quantitative microbial risk assessment (QMRA) model
for Salmonella spp. in minced pork meat. The input parameters were grouped according to
four successive exposure pathways: (1) primary production (2) transport, holding, and slaughterhouse,
(3) postprocessing, distribution, and storage, and (4) preparation and consumption.
An inventory of 101 potential input parameters was used for building the QMRA model. The
characteristics of each parameter were defined using a standardized procedure to assess (1)
the source of information, (2) the sampling methodology and sample size, and (3) the distributional
properties of the estimate. Each parameter was scored by a panel of experts using
a pedigree matrix containing four criteria (proxy, empirical basis, method, and validation)
to assess the quality, and this was graphically represented by means of kite diagrams. The
parameters obtained significantly lower scores for the validation criterion as compared with
the other criteria. Overall strengths of parameters related to the primary production module
were significantly stronger compared to the other modules (the transport, holding, and
slaughterhouse module, the processing, distribution, and storage module, and the preparation
and consumption module). The pedigree assessment contributed to select 20 parameters,
which were subsequently introduced in the QMRA model. The NUSAP methodology
and kite diagrams are objective tools to discuss and visualize the quality of the parameters in
a structured way. These two tools can be used in the selection procedure of input parameters
for a QMRA, and can lead to a more transparent quality assurance in the QMRA.