Congressoman Rosa DeLauro (D-CT) sent a letter yesterday to the U.S. Department of Agriculture (USDA) Office of the Inspector General (IG) calling for an investigation of beef testing protocol.

DeLauro requested that the IG look into the scientific merits and identify any shortcomings of the USDA’s N-60 testing system for beef, which requires the USDA’s Food Safety and Inspection Service (FSIS) to to remove 60 pieces of product from a lot to allow for testing for pathogens like E. coli O157: H7. 

The N-60 protocol is the method most large beef trim manufacturers use to try to verify their beef is E. coli-free.

“To protect public health, verification testing must be robust and ensure that adulterated product is not sold to the American consumers,” DeLauro wrote in the letter. “I am troubled by the shortcomings of the N-60 test and the associated food safety implications, and that is why I am requesting an investigation into the scientific merits of this beef testing protocol.”

DeLauro’s letter, addressed to Phyllis K. Fong, who has been IG at USDA since 2002, asks the agency several specific questions regarding the N-60 testing program’s statistical validity, sample collection and analysis, and application of test results.

DeLauro sent the following list of questions to the IG:


Statistical Validity of N-60 Testing


  • What is the prevalence of E. coli O157:H7 in domestic beef trim used for raw ground beef production at processing facilities in the United States? When and how was this estimate reached? How frequently will it be re-assessed?
  • What is the confidence level of the N-60 sampling method as currently performed? Is that level appropriate for ground beef?
  • What is the definition of a product “lot” used in the N-60 testing and how was this definition determined? How is this definition applied to individual processing establishments? Is this an appropriate application?
  • How does this definition affect the statistical viability of this test? How confident are we that lots testing negative are truly negative if the definition of “lot” varies among establishments?

 Sample Collection and Analysis


  • Are all samples collected, stored, shipped, and analyzed by trained FSIS employees?
  • Are laboratories instructed to reject samples that do not meet minimum quality standards? If so, what are those minimum quality standards? How is it assured each sample meets them? 
  • Are the minimum standards associated with sample collection, storage, shipment, and analysis adequate? What type of testing standards must be met by laboratories analyzing the samples?
  • Because E. coli O157:H7 is not necessarily distributed homogenously in a product, how did the agency decide on its current collection methodology? Are samples collected truly representative of the entire lot? 

 Application of N-60 Test Results


  • Has FSIS established a protocol for reassessing an establishment’s HACCP plan based upon N-60 test results? What actions are taken at an establishment after a positive N-60 test result?
  • What is the implication of a positive N-60 test result on the individual lot tested? On other lots from the same establishment produced on the same date?
  • How are the FSIS N-60 test results and the establishment’s N-60 test results correlated? How do N-60 testing protocols differ between FSIS and the industry?
  • What are the implications of the USDA label associated with a negative N-60 test?