What color does E coli change for Voges-Proskauer test?

In the Voges-Proskauer test, Escherichia coli (E. coli) typically does not produce a color change, as it is usually negative for this test. However, if the test is positive, the solution will turn a reddish color, indicating the presence of acetoin. This test is used to differentiate between various species of enteric bacteria based on their ability to ferment glucose and produce certain metabolites.