PR Sugar

PR broths are created with peptone, phenol red, and the test sugar of choice. Like other sugar tests, near any sugar can be added for testing, though only a few are necessary for these tests. The test only tests for fermentation, so any other type of sugar utilization will be ignored by the indicator dye. Acid production from fermentation will cause the media to turn yellow from it's typical red. Gram negative organisms will give a very bright yellow, gram positives typically give a distinctive gold color in this media.