Quarterly Progress Report on Salmonella Testing of Selected Raw Meat and Poultry Products: Preliminary Results, April - June, 2006
In February 2006, FSIS announced several changes | PDF to the Agency's Salmonella Verification Testing Program. Changes included testing of turkey carcasses, increasing the testing frequency in establishments that exhibit highly variable or variable process control, and posting quarterly results to the FSIS Web site. This is the second quarterly report for 2006 and covers the months of April through June.
A new process for scheduling Salmonella sets was implemented for the sets scheduled in June 2006. The new procedures focus both inspection and laboratory resources on establishments that have had the most samples positive for Salmonella and the most samples with serotypes most frequently associated with human salmonellosis. In July FSIS posted a one page document explaining the scheduling criteria that were used to schedule Salmonella sets beginning in June. To view the document, visit FSIS' Web site at http://www.fsis.usda.gov/pdf/scheduling_criteria_salmonella_sets.pdf (PDF Only). The new scheduling criteria are viewed as preliminary in nature and will be continually reassessed and modified as needed. However, the overall objective of a risk-based approach to verification sampling will be a constant.
In addition to changing the scheduling criteria in June, the Agency also initiated the testing of turkey carcasses using the "baseline guidance results" that were originally published in the February 17, 2005 Federal Register Notice (70 FR 8058) regarding "Generic E. coli and Salmonella Baseline Results," specifically addressing turkeys (http://www.fsis.usda.gov/OPPDE/rdad/FRPubs/02-046N.pdf, PDF Only). This guidance specifies a maximum of 13 positive samples in a set of 56 samples. That guidance was based on results from the turkey carcass sponge baseline study conducted from July 1997 through June 1998 ( http://www.fsis.usda.gov/PDF/Baseline_Data_Young_Turkey.pdf , PDF Only). The "baseline guidance results" for turkey carcasses were also addressed in the February 2006 FR Notice. The results for the first 407 turkey carcass samples collected in June are contained in Table 1.
Finally, in June, the Agency also initiated a change where inspected establishments receive individual sample results as soon as they are available. Previously, establishments only received completed set results.
When FSIS published the results from the first quarter of 2006, the data were presented in two formats. Those same two formats are included here. First, Table 1 shows the summary of all second quarter "A" samples in the same format used in past annual reports. The second format showing the results is a graph for each product (PDF Only) showing the number of samples and the percentage of positive samples by quarter for the last five quarters. The Agency will continue this format for now. The Agency included the five-quarter graphs for all products, recognizing that the number of samples can be very small, or even zero, for some products in a specific quarter. Annual reports summarizing results for calendar years will continue to be available on the FSIS Web site. However, due to the restructuring of how Salmonella sets are now scheduled, comparisons of results for this year to previous years will be highly inappropriate. FSIS is also considering posting results by fiscal year as well as calendar year.
For the second quarter, FSIS has continued to include only "A" samples in Table 1 since most of the samples collected in the second quarter were scheduled under the previous scheduling procedures. Under those procedures, "A" sets were scheduled differently than follow-up "B" and "C" sets. "A" sets were randomly scheduled from new establishments or establishments that had passed their previous set. "B" and "C" sets were scheduled by District Offices based on the implementation of preventive and corrective actions following a set that failed to meet an existing performance standard. With the new scheduling criteria, all sets will be scheduled using the same criteria. Future quarterly reports will have one table for all results except for "B" and "C" sets that were scheduled prior to June 2006. In future reports, FSIS will no longer use the terminology of "A", "B" and "C" sets.
In the initial quarterly report, the Agency noted that as the proportion of samples from establishments with highly variable or variable process control increases, the percentage of Salmonella-positive samples could increase, especially in the immediate future. This could happen even though the true industry-wide prevalence was actually decreasing. Clearly, given the revised testing strategy, the percentage of positive samples will no longer be useful as an indicator of trends in the overall industry. Thus FSIS has been considering alternative trend indicators for the Salmonella verification program.
For this quarterly report, the Agency is illustrating in Table 2 one type of new trend indicator using broiler (young chickens) establishments as an example. This trend indicator is the proportion or percentage of establishments in the three categories identified in February. Other products will be added to future quarterly reports as appropriate data are available. In addition, FSIS will continue to consider other trend indicators.
The Agency does not expect the trend indicator of "proportion of establishments by category" to change much on a quarterly basis. This trend indicator should, however, track overall industry performance when examined over multiple years. For this quarterly report, FSIS is using broilers (young chickens) as an illustration and will add more product categories as appropriate data is available.
To generate Table 2, the Agency used the historic data and sorted broiler establishments into the three categories presented in the February Federal Register Notice. As seen in Table 2, the majority of broiler establishments are currently in Category 2 (54.5% as of July 1, 2006). The February 2006 FR Notice stated a goal of having 90% of establishments in Category 1 after one year under the revised sampling system.
FSIS has also recognized that changing the verification program will prevent valid comparisons of testing results over time (e.g., quarter-to-quarter or year-to-year trends). However, results of upcoming nationwide baseline studies can be used to provide valid estimates of the prevalence of certain pathogens of public health concern and permit valid statistical comparisons to be made over time. A 12-month Young Chicken (Broiler) Baseline Study is scheduled to begin shortly, and additional baseline studies are under development.
Note: Updates of Salmonella serotype information will be provided in a separate report.
|* Preliminary data
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| Table 2, Broiler Establishments By Category
| * An establishment that is currently operating and subject to sampling, but without a minimum of one completed set.
** Total number of establishments currently operating and subject to sampling.
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