FLUID TETRATHIONATE MEDIUM W/O IODINE AND BG (TETRATHIONATE BROTH BASE W/O IODINE & BG)

Salmonella are ubiquitous in the environment. These organisms are usually present in small numbers compared to coliforms; therefore, it is necessary to examine a relatively large sample to isolate the organisms. Salmonella present in food samples may be sub lethally damaged during various stages of food processing where they may be exposed to low temperatures, heat drying, radiations, various chemicals. These damaged cells are able to cause spoilage, and if ingested cause diseases under favorable conditions. Therefore, it is important to resuscitate these damaged bacteria before enumeration. Fluid Tetrathionate Medium (with added iodine and brilliant green) is recommended for the selective enrichment of Salmonella including Salmonella Typhi from faeces, urine, food and other material of sanitary importance. The medium, originally formulated by Mueller is recommended by APHA for enrichment of Salmonella. Due to the addition of iodine and potassium iodide, tetrathionate is formed in the medium. Organisms possessing the enzyme tetrathionate reductase grow in this medium.
Aseptically inoculate test specimen into Fluid Tetrathionate medium (with added iodine and brilliant green) and incubate at 35-37?C for 18-24 hours. Following the incubation, isolate onto selective media plates. Refer standard procedures for enrichment and isolation.

for isolation of salmonellae from food, urine, faeces and other material of sanitary importance