Related Documents and Data Tables

• Data in Excel (XLSX) format | PDF Document
  This dataset includes calendar year 2016.
• FSIS Estimation of Pathogen Rates in the Population Represented by the Samples Collected in Each Sampling Project for Fiscal Year 2015 (PDF Only)

FSIS calculates prevalence, volume weighted percent positive, or percent positive calculations for microbial pathogens in FSIS regulated products that are currently sampled through existing sampling projects. [1],[2] FSIS evaluated its sampling projects in 2012 to determine if they could be used to calculate prevalence; this evaluation was used to guide the development of these calculations. [3],[4] FSIS intends to provide new calculations each quarter using the prior 12 months of sampling data.[5]

Overview

Depending on the data available, calculations will either be percent positives, volume-weighted percent positive, or prevalence.[6] When possible, the calculations will include upper and lower confidence bounds.

• Percent positive (PP) – The percentage of samples of a specific FSIS-regulated product with a specific pathogen. These calculations may vary significantly from the actual prevalence of the population, but FSIS cannot make a more precise calculation with the data currently available.
• Volume weighed percent positive (VWPP) – The VWPP for a specific product-pathogen pair is calculated by combining the production volumes (production volume can be defined as the amount (weight or numbers of head) of product produced per year) for establishments with their sampling results. This provides a more accurate estimation than a percent positive, but the data do not meet the statistical requirements to make a prevalence estimate. VWPP is more public health focused than PP, in that weighting results by volume reflects exposure of the public to specific pathogens.
• Prevalence– The estimated proportion, nationally, of a specific FSIS-regulated product with a specific pathogen.