This environment is used for the differentiation of Enterobacteriaceae by the ability to deaminate phenylalanine. For the analysis of the environment is prepared in the form of the slanted agar in test tubes. The research culture is inoculated and cultured at 37 ° C for 24 hours. At the end of cultivation in test-tube add ferric chloride solution, and the mixture turns green in color. In the process of growth of a culture which is able to deamination phenylalanine ammonia which is formed when additions of iron ions to form a green complex.