1. Maintenance Media: For carrying the stock culture to preserve the viability and sensitivity of the test organism for its intended purpose 2. Inoculum Media: To condition the test culture for immediate use 3. Assay Media: To permit quantitation of the vitamin under test. They contain all the factors necessary for optimum growth of the test organism except the single essential vitamin to be determined.

Pyridoxine Y Medium is patterned after the formulation of Campling and Nixon,1 and modified by Hurley2 and Parrish, Loy and Kline.3 This medium is used in the microbiological assay of pyridoxine using Saccharomyces cerevisiae ATCCTM 9080 as the test organism.

As Reported

Store at 4°C. Stable for 6 months after receipt.

Yellow, clear liquid. Slight precipitate may form.