We propose a sampling plan optimized to produce public health risk estimates related to microbiological contamination in food according to the following definition:
“Distribute the sampling capacity of the food safety authority over products in retail according to their relative contribution to the microbiological public health risk within the available budget."
Purpose
Develop a monitoring program including those pathogen/product combinations that will capture as many Disability Adjusted Life Years (DALYs) as possible for the least amount of money.
Methods
Estimating food related microbiological public health risks involves knowledge about different variables. Beside prevalence and concentration data of specific pathogens in specific food products and consumption data, food handling by consumers and human exposure are important aspects for the ultimate risk.
Exposure assessment was combined with DALYs and a monitoring budget which resulted in the following optimizing criteria for risk based sampling:
A. Exposure to a certain pathogen depending on the consumed amount of its associated food product, pathogen concentration and food preparation,
B. Based on exposure estimates, attribute contributions of pathogen/product combinations (from A.) to disease burden expressed in DALYs for pathogen-product groups,
C. A predefined uncertainty in the risk estimate (expressed in the prevalence) and subsequent amount of samples needed of products in A,
D. Costs per sample.
The optimizing criterion is (C * D)/B and has the units costs per DALY.
Results
The method is explored using five case studies: Campylobacter in pork and poultry, Salmonella and Toxoplasma in pork, Shiga-toxin producing E. coliin beef.
Significance
A risk based sampling plan will help authorities to monitor the prevalence of the most important pathogen/product combinations from a public health risk perspective in a consistent manner (e.g., by trend analysis) and, with that, allowing them to advise on targeted intervention programs.