Culture-Based Isolation of Salmonella from Different Matrices

While Salmonella is a leading bacterial cause of foodborne illness, its relative abundance in food, animals, and the environment is low. This necessitates the use of cultural enrichment to reduce the background flora and enable Salmonella to proliferate so that it can be subsequently isolated on agar or detected via molecular methods. Further, successful Salmonella isolation is often dependent on the sample type, or matrix, from which it is being isolated. Particularly where matrices have high microbial background, or high levels of organic material, attention should be paid to culture methods, as an additional enrichment step is often required. Here we share methods for Salmonella isolation from three very different matrices: pre-harvest chicken production, post-harvest chicken carcasses, and surface water (Fig. 1). Pre- and post-harvest chicken samples consider the same animal but represent two vastly different microbiological matrices, and this impacts how Salmonella is isolated. Conversely, surface water serves as an example of an environmental sample where Salmonella (and other enteric microbes) may be under significant stress (e.g., osmotic stress, exposure to UV radiation, etc.), and this can also influence success in Salmonella isolation.