EC O157:H7 Enrichment Broth is recommended as an enrichment broth for the rapid growth of E. coli O157:H7 from food samples.This medium is designed for the rapid enrichment of Ecoli 0157: H7. Tryptone provides nitrogenous, carbonaceous compounds and other essential growth nutrients. Yeast extract serves as a source of vitamin B complex and other nutrients. Bile salt mixture inhibits most of the gram-positive organisms.