Facts:

• Glucose assimilation test is based on the ability of a bacterial species to utilize glucose as a sole carbon source. The test is designed to determine whether the organism can use glucose as its sole energy source and carbon source to support growth.
• API kits include "Glucose assimilation test" as an assimilation test [Figure]

Question:

Is there a conventional, less expensive and accurate method for performing glucose assimilation test without using an API kit?

Is it hard to get your hand on a growth medium with only a single type of carbohydrate, in another word, pure?

Is in-lab contamination with other types of carbohydrates (or even other carbon sources) a common occurrence in conventional methods (if there any)?