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.

This update is a good reminder to make sure establishments are making the most of the information they receive in their quarterly letters. FSIS began issuing the quarterly letters in February 2016. The quarterly letters summarize an establishment’s sampling results for the past 12 months (except the data underlying the Performance Standard summary includes the last 15 months of results). The quarterly letters are divided into sections for product types and only include the product types that are relevant for the establishment. 

Quarterly letter contents

The quarterly letters begin with a set of summary tables that provide an overall snapshot of pathogen prevalence in an establishment. The summaries explain how the facility compares to performance standards, the number of positive samples for each pathogen by product type, and the residue testing results of all slaughter subclasses (e.g., beef cow, steer) sampled in the preceding 12 months.

Next are summaries of testing results for each product category over the previous 12 months. The information includes (1) the number of samples collected; (2) the pathogen tested for; (3) the number of positive results compared to the number of samples analyzed; (4) the percent of positive results; and (5) the industry percent positive for comparably sized facilities.

The quarterly letter also breaks down detailed test results that pertain to the positive samples. This could include (where applicable) Salmonella serotypes, positive samples for Campylobacter, PFGE pattern names for isolates, the type of antimicrobial resistance profile, the non-O157 STEC O groups recovered, and/or L. monocytogenes (in ready-to-eat products). FSIS also provides a description of the distribution of Salmonella serotypes recovered during the previous 12-month period.

For slaughter establishments, FSIS also provides a summary of residue testing of animal carcasses, by animal type, (1) scheduled samples, (2) collector generated samples, (3) in-plant tests, (4) lab-analyzed in-plant samples, (5) the number of violative animals, and (6) the number of violative residues/analytes.

Quarterly letter takeaways

The quarterly letters conclude with an explanation of how FSIS uses the sampling results and how the establishment should use them. Specifically, FSIS recommends that an establishment use the information in the quarterly letters to evaluate the effectiveness of their overall HACCP system processes and take preventive actions. The agency will expect an establishment to place a particular emphasis on test results indicating a persistent single strain (i.e., harborage) or identify strains associated with recent clinical illnesses that are closely related by WGS or have indistinguishable PFGE patterns. Note, a clinical illness is “recent” if it was entered into PulseNet within 90 days of FSIS sampling.

FSIS uses an establishment’s sampling data to determine if additional testing is necessary. Some of the specific sampling data the agency will rely on includes: serotype, WGS, PFGE patterns, and Antimicrobial Susceptibility Testing. FSIS will also evaluate for the presence of any adulterant when determining proper follow-up actions, including sampling. 

FSIS also uses sampling results to supplement other establishment-specific information when it considers further actions involving a facility, such as (1) reviewing records, (2) initiating food safety assessments, (3) intensified testing, or (4) forming incident investigation teams. Further, after considering an establishment’s noncompliance history and sampling results, which includes evaluation of whether the establishment considered FSIS verification sampling in their evaluation of their HACCP system, FSIS may determine an establishment may have ineffective HACCP system.  NP