Occurrence of Salmonella in the environment

Abstract

Salmonella is one of the most common causes of foodborne diseases. Although it is an intestinal bacterium, it can function perfectly well in various environments outside the host’s organism. Salmonella infections in humans are transmitted mainly through food of animal or plant origin and pose a serious problem for public health and the economy. Salmonella is an etiological factor of diseases in farm and free-living animals, which are also the most common source of environmental contamination. Reptiles and amphibians represent an important and often underestimated reservoir of these bacteria. Even under unfavorable conditions, the pathogen can survive for years in feed or food processing facilities mainly because of its ability to form biofilm. Salmonella can colonize plants epiphytically and endophytically. After penetrating external tissues, it can be transferred through the internal transport system to various organs, including fruit and seeds. This process depends on the serovar of the bacteria and the species of the plant being infected. The ability of Salmonella to survive and proliferate in the soil depends on many interacting factors, such as soil type, humidity, pH, temperature, and indigenous flora. Enriching the soil with natural fertilizers increases the occurrence of the pathogen and significantly reduces its rate of decline. In the aquatic environment, as well, Salmonella can survive for months after direct contamination with human or animal faeces or indirect contamination with insufficiently treated sewage sludge or runoff from agricultural land. The main determinants of Salmonella survival are temperature, sunlight, and the presence of accompanying microflora. Contaminated water used in processing can also be an indirect cause of transmission of intestinal pathogens to food.