This document reviews the previously used versions of the Listeria monocytogenes risk ranking algorithm and provides information on two updates of the algorithm for establishments producing RTE products under the Interim Final Listeria Rule (9 CFR 430). The information provided here complements and expands on the data and results of the 2007 FSIS Risk Assessment for Risk-Based Verification Sampling of Listeria monocytogenes. That document used FSIS Listeria monocytogenes sampling verification data from calendar years 2005 and 2006 to evaluate and update the original 2005 risk ranking algorithm. This document uses FSIS Listeria monocytogenes sampling verification data from calendar year 2008 for two additional updates of the risk ranking algorithm. Data from calendar year 2008 was selected for analysis because it provided the largest sampling frame among calendar years 2005 through 2011. The 2011 risk ranking algorithm version is presently being evaluated for performance in the FSIS Public Health Information System (PHIS). PHIS was fully implemented as the replacement for the previous Performance Based Inspection System (PBIS) in January 2012 which managed the monthly Listeria monocytogenes risk ranking algorithm establishment sampling schedule prior to converting over to PHIS. The algorithm is now fully implemented in PHIS. A document regarding the changes made to the algorithm to conform with PHIS will be forthcoming in an additional algorithm update.