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Review of FSIS Risk Assessment for Listeria monocytogenes in Deli Meats

Investigators
Petersen, Barbara; Barraj, Leila
Institutions
Exponent, Inc
Start date
2005
End date
2015
Objective
The purpose of this review was to determine if the FSIS Risk Assessment for Listeria monocytogenes (LM) in Deli Meats model worked as described and to examine the impact of alternative model input assumptions on model calibration, intervention options and conclusions.
More information
Conclusions
In general, the FSIS model works as described in the FSIS report. The formulas used to model the mass balance approach are correctly implemented. The distribution used in the calibration to represent listeria concentrations in deli meats at retail correctly simulates the data in FDA/FSIS risk assessment. The number of iterations used in the risk assessment (1,000,000 iterations) is sufficient for the model output to stabilize. However, the distribution used by FSIS to represent the amount of listeria added during a contamination event is not necessarily the distribution that resulted in the best fit when compared to that based on the data in FDA/FSIS risk assessment. Correlation between the duration of a contamination event, the interval between contamination events, or the number of Listeria organisms transferred to the FCS is not allowed in the FSIS in-plant model.

Deliverable
Alternative parametric distribution for specific variables may be needed, or there may be other model construct limitations. FSIS’s conclusions about the relative effectiveness of various intervention scenarios remain questionable.

Funding Source
Fndn. for Meat and Poultry Research and Education
Project number
03-600
Categories
Listeria
Risk Assessment, Management, and Communication
Commodities
Meat, Poultry, Game