The four keystones of quantitative risk assessment are hazard identification, exposure assessment, dose-response assessment and risk characterization. This paper considers the different steps of risk assessment and their application to food microbiology. Traditionally, quantitative risk assessment has been viewed simply as a method to estimate risk. However, when we conduct a complete risk assessment including different factors from "farm to fork" it can serve to understand the risk process. Quantitative risk assessment can also provide valuable insights as how to best manage the risk.