In a Tween 80 hydrolysis test, a positive result is indicated by what color change?

A positive result in a Tween 80 hydrolysis test is indicated by an amber color change. Tween 80, or polysorbate 80, is a surfactant that can be hydrolyzed by certain bacteria. During this process, fatty acids are released, which can lower the pH of the medium. The color change to amber shows the acidic nature of the hydrolyzed products, confirming that the organism being tested can utilize Tween 80 as a carbon source. This test is often used in microbial identification to differentiate organisms based on their ability to hydrolyze Tween 80.