The process of systematic review and its application in agri-food public-health

Foodborne illness is an important public-health concern. Livestock operations represent the original source of many foodborne pathogens. Policy- and decision-makers in the area of agri-food public-health need dependable information on interventions to reduce foodborne diseases. While individual studies might be weak or reach contradictory conclusions, the body of information contained in all studies might reveal a clearer picture of the state of knowledge. A formal process has been developed for conducting systematic reviews of the human healthcare literature. Systematic reviews differ from traditional narrative reviews in that systematic reviews follow a structured research protocol to reduce sources of bias at all stages of the review. This includes the objective, the literature search, the identification of relevant literature, quality assessment of relevant studies, summarization or statistical analysis of data, and conclusions. To date, systematic reviews have not been widely used in agri-food public-health. Existing systematic reviews on agri-food public-health topics revealed a scarcity of rigorously conducted intervention research, indicating a need for additional high quality primary studies. The specific protocols used to conduct systematic reviews in agri-food public-health need to accommodate the use of challenge studies and observational studies, the lack of randomized controlled trials, and the clustering of animal populations. (c) 2006 Elsevier B.V. All rights reserved.