YM Agar and Broth, is a selective growth medium with low pH useful for cultivating yeasts, molds, or other acid-tolerant or acidophilic organisms, while deterring growth of most bacteria and other acid intolerant organisms.[1] It is Malt extract medium modified by the addition of Yeast extract and peptone.[2]
The 'YM' of the name stands either for 'Yeast and Mold', or 'Yeast extract-Malt extract' depending on the source.