Risk Assessment for Listeria monocytogenes in Ready-to-eat Meat and Poultry Products
Various control methods used in the meat and poultry processing environment to mitigate listeriosis were evaluated using a dynamic in-plant Monte Carlo model. These control methods included food contact surface testing, sanitation, post-processing lethality treatment, and product formulation with microbial growth inhibitors. The dynamic in-plant model served as an input into the risk assessment model developed by the FDA and FSIS in 2003 which predicts the number of deaths and illnesses resulting from the use of each control method. The use of growth inhibitors combined with a post-processing lethality step was estimated to save over 200 more lives than the FSIS proposed minimum sampling standard.
An analysis of data collected by the National Alliance for Food Safety and Security (NAFSS) found that retail-sliced deli meats have a greater prevalence and concentration of L. monocytogenes than prepackaged deli meats. Cross contamination at the retail level is suspected due to clustering of sample positives by store and the influence of sampling time of day on the prevalence of L. monocytogenes.
The comparative risk of Listeria monocytogenes in retail sliced versus prepackaged deli meats was evaluated using a modified version of the 2003 FDA-FSIS risk assessment model which considered slicing location and the use of growth inhibitors. The comparative risk ratio for the number of deaths from retail-sliced versus prepackaged deli meats was found to be 9.1 and retail-sliced product with a growth inhibitor was found to be at greater risk for listeriosis than prepackaged product without growth inhibitor.