Question

citrate test consider the uninoculated tube. a) is it a positive or a negative control? b) what information is provided by the uninoculated control?

Answer 1

A) It is a Negative Control

B) It provides a baseline color (green) for "no change' in the medium. This allows detection of slight color changes in the experimental tubes that might not be apparent without comparison to the original color. It also verifies the sterility of the medium.