Investigational tracing as a method for identification of causative foods and sources of food-borne outbreaks

Often, food-borne outbreaks cannot be clarified. One reason for this is that foods are no more available for testing once the outbreak is detected. Specifically, this can be the case for foods with a short shelf-life, such as plant foods. Moreover, sometimes the food matrix leads to performance failures of laboratory methods. In such situations, investigational tracing can be the key to outbreak clarification. The analysis of food flows in supply chains can display epidemiological correlations, show the extent of events and may allow rapid outbreak containment. This article presents three examples of outbreaks where the causative agent and/or the transmitting vehicle were unknown. Batch-precise traceability studies first helped to narrow down the list of questionable foods and later to identify the causative vehicles and their sources. Investigational tracing of food flows is a powerful tool for rapid outbreak clarification and specifically helpful for causative foods that are easily perishable and/or contaminated with viruses.