The identification and differentiation of bacteria date back to the late 1800s. Primary interest often focused on microorganisms impacting animal or human health. Salmonella falls under this umbrella, as it was first identified during a hog cholera study in the 1880s. Early work relied on phenotypic (observable) characteristics due to the limitations of the science at the time, but advancements in science led to the initial development of an antigenic schema for Salmonella. Over the ensuing years, the use of phenotypic and antigenic characteristics helped define the taxonomy of Salmonella (>2600 serovars). These characteristics have also been used for decades in public health investigations involving foodborne illnesses. Linking a Salmonella isolate from an ill human to a Salmonella isolate from a food through serotyping played a critical role in these investigations. Continue Reading