In order to successfully enrich for Lactobacillus casei we decided to use Lactobacillus Selection Oxgall Agar. To enrich for an organism means to provide specific conditions that enhance the growth of the organism in a mixed population. Oxgall is dehydrated fresh bile and is used for the selection of bile tolerant bacteria. According to the Encyclopedia of Food Microbiology L. casei tolerates high acid levels. The Lactobacillus Selection Oxgall (LSO) Agar is used for the selective isolation, cultivation and enumeration of Lactobacillus casei. After reading through The Handbook of Microbiological Media, we determined that the most suitable agar to be used to isolate L. casei would be LSO Agar.