The limits of food safety testing: A case study of Escherichia coli testing of beef trim

Beef trim, the primary component of ground beef, is tested by both the Food Safety and Inspection Service (FSIS) and meat packers for Escherichia coli O157:H7 under a zero tolerance standard. We compare and contrast the process control and filtering roles of this testing on costs and food safety outcomes. Both of these roles of testing have been alternatively emphasized in recent legislative proposals and policy statements on beef trim testing. In the process control role, test design - including the decisions to increase sample sizes, re-test lots, and change tolerance thresholds - only affects the cost of implementing a targeted food safety standard, but does not directly affect health outcomes. In contrast, in the filtering role, test design influences the likelihood of errors and directly affects health outcomes. Neither role eliminates all risk from this pathogen. More broadly, we discuss the incentives food producers face to increase their frequency of testing and improve food safety processes in response to positive test findings as the process control role emphasizes.