On Sept. 21, the U.S. Department of Agriculture’s Food Safety and Inspection Service (FSIS) issued Notice 48-18, “Quarterly Establishment Information Letters About Sampling Results,” which indicated an update to FSIS’ quarterly establishment information letters to include whole-genome sequencing (WGS) findings for Listeria monocytogenes instead of pulse-field gel electrophoresis (PFGE).
The update to the Quarterly Establishment Information Letters (quarterly letters) reflects recent changes in pathogen characterization methods. As of Jan. 15, 2018, FSIS and the Centers for Disease Control and Prevention are now using WGS to characterize L. monocytogenes isolates rather than PFGE. As a result, WGS findings for L. monocytogenes is being reported in quarterly letters, specifically Multi-locus Sequence Typing (MLST). FSIS still has the capability to perform PFGE analysis as well as other WGS analyses. PFGE analysis will continue for other pathogens and will still be reported in the quarterly letters.