THE APPLICATION OF QUANTITATIVE RISK ASSESSMENT TO MICROBIAL FOOD SAFETY RISKS

Regulatory programs and guidelines for the control of foodborne microb ial agents have existed in the U.S. for nearly 100 years. However, inc reased awareness of the scope and magnitude of foodborne disease, as w ell as the emergence of previously unrecognized human pathogens transm itted via the foodborne route, have prompted regulatory officials to c onsider new and improved strategies to reduce the health risks associa ted with pathogenic microorganisms in foods. Implementation of these p roposed strategies will involve definitive costs for a finite level of risk reduction. While regulatory decisions regarding the management o f foodborne disease risk have traditionally been done with the aid of the scientific community, a formal conceptual framework for the evalua tion of health risks from pathogenic microorganisms in foods is warran ted. Quantitative risk assessment (QRA), which is formally defined as the technical assessment of the nature and magnitude of a risk caused by a hazard, provides such a framework. Reproducing microorganisms in foods present a particular challenge to QRA because both their introdu ction and numbers may be affected by numerous factors within the food chain, with all of these factors representing significant stages in fo od production, handling, and consumption, in a farm-to-table type of a pproach. The process of QRA entails four designated phases: (1) hazard identification, (2) exposure assessment, (3) dose-response assessment , and (4) risk characterization. Specific analytical tools are availab le to accomplish the analyses required for each phase of the QRA. The purpose of this paper is to provide a description of the conceptual fr amework for quantitative microbial risk assessment within the standard description provided by the National Academy of Sciences (NAS) paradi gm. Each of the sequential steps in QRA are discussed in detail, provi ding information on current applications, tools for conducting the ana lyses, and methodological and/or data limitations to date. Conclusions include a brief discussion of subsequent uncertainty and risk analysi s methodologies, and a commentary on present and future applications o f QRA in the management of the public health risks associated with the presence of pathogenic microorganisms in the food supply.