HiCombi™ Dual Performance Salmonella Medium

Principle And Interpretation

Salmonella species are the leading cause of food-borne bacterial diseases in humans. The problem of human salmonellosis from consumption of contaminated foods generally remains on the increase worldwide (1)

The ubiquity of Salmonellae in the natural environment, compelled with the intensive husbandry practices used in the meat, fish and shellfish industries and the recycling of offal and inedible raw materials into animal feeds has favored the continued preeminence of this human bacterial pathogen in the global food chain (2, 3) of the many sectors within the meat industry, poultry products remain the principal reservoirs of Salmonellae.

Salmonella species causes many types of infections from mild self-limiting gastroenteritis to life-threatening typhoid fever. The most common form of Salmonella disease is self-limiting gastroenteritis with fever. Typhoid fever is characterized by fever, headache, diarrhea and abdominal pain. Salmonella Typhi and Salmonella Paratyphi A & B cause gastroenteritis, bacterimia and enteric fever, Salmonella Choleraesuis causes gastroenteritis and enteric fever.

Lab diagnosis depends on the isolation and identification of Salmonella from food samples.

Detection by Conventional methods – enrichment, isolation and confirmation requires 3-4 days. On the first day, the food sample is inoculated into enrichment media like Tetrathionate Broth or Selenite F Broth. On the second day the enrichment from broth is plated onto selective media like SS agar, XLD or DCA Agar. For confirmation colonies are then selected and inoculated into any confirmatory media such as Triple Sugar Iron Agar, Urea Broth and other biochemical media for biochemical tests.

The dual performance bottle allows faster confirmation of the causative organism, eliminating the waiting period of 3-4 days giving results in just 24 hours. The combination media ensure enrichment as well as isolation and colonies can be visualized in 24 hours and confirmed. Peptone special, lactose and sucrose provide necessary nitrogenous and carbonaceous compounds for growth of Salmonella. Bile salts along with indicator mixture inhibit other enteric bacteria present in food sample.