A comprehensive review on the current status of culture media for routine standardized isolation of Salmonella and Shigella spp. from contaminated food

Abstract

Salmonella spp. is an important foodborne pathogen and a leading cause of foodborne outbreaks worldwide. Shigella spp. is considered an important foodborne pathogen in low-income countries in Asia and Africa, where it is believed to be endemic in these regions. A broad range of selective plating and enrichment media have been formulated to detect and assess Salmonella and Shigella spp. during the outbreaks of food-related infections and regular food surveillance investigations. To date, culture media-based methods remain standard methods for the microbiological analysis of food and are approved by the World Health Organization (WHO), Food and Drug Administration (FDA), U.S. Environmental Protection Agency (US EPA), and Food and Agriculture Organization (FAO). This review elaborates on current culture media, which are employed in culture-based standard methods for Salmonella and Shigella spp. isolation and detection from food samples. The specificity and regulatory acceptance of time-consuming conventional culturing methods make them ‘gold standard’ pathogen detection protocols. However, alternate strategies become necessary because of culture methods’ low sensitivity and inability to detect viable but non-culturable (VBNC) cells. The recent approaches with improved detection efficiencies include molecular techniques (PCR), DNA hybridization, and chromogenic culture media. Similarly, the usage of nanoparticles and immunosensors is also rising for pathogen detection. The integration of novel and conventional approaches could enhance the reliability, and sensitivity of routine pathogen surveillance.