In this lab students perform a test on two different bacteria to determine whether the organisms can use citric acid as their sole carbon source. The citrate test is often performed as part of the IMViC (Indole, Methyl Red, VogesProskauer, and Citrate) series of tests used to differentiate common species of enteric bacteria.
This activity assumes that students have previously worked with bacteria and are familiar with sterile technique. It also assumes they have a basic knowledge of pH. If this is not the case, we recommend that students complete the activities described in our “Introduction to Sterile Technique” LabSheet before beginning this activity.