M17 Agar is used for isolating and enumerating lactic streptococci in yogurt, cheese starters and other dairy products.

Principles M17 Agar contain peptones and meat derivatives as sources of carbon, nitrogen, vitamins and minerals. Yeast extract supplies B-complex vitamins which stimulate bacterial growth. Disodium-β-glycerophosphate buffers the medium as acid is produced from fermentation of lactose. Ascorbic acid stimulates growth of lactic streptococci. Magnesium sulfate provides essential ions for growth. Agar is the solidifying agent in M17 Agar.