Christopher's Semisolid Brucella Medium Base is recommended for selective enrichment of Campylobacter species from food. This medium was described by Christopher and is also recommended by APHA for enrichment of Campylobacter species from food using MPN technique. The antibiotic supplement makes the medium selective for the isolation of Campylobacter species. Sodium bisulphite is a reducing agent and sodium chloride maintains osmotic equilibrium of the medium. Sodium pyruvate serves to enhance the growth of Campylobacter species.