Product Summary and Explanation
In 1915, Clark and Lubs demonstrated that colon-aerogenes family of bacteria could be divided into two
groups based on their action in a peptone and dextrose medium.1 When tested with the pH indicator methyl
red, the “coli” group produced high acidity while the “aerogenes” group produced a less acid reaction. The
test to detect high-acid end products is known as the Methyl Red (MR) test. The test to detect less-acid end
products is based on the procedure described by Voges and Proskauer in 1898.2
A color reaction occurs
when certain cultures, incubated in a medium containing peptone and dextrose, are treated with potassium
hydroxide and exposed to air. This reaction detects the formation of acetylmethylcarbinol, known as the
Voges-Proskauer (VP) test.