ATP bioluminescence testing is used to assess cleaning by detecting what?

• A. Biological residues
• B. Bacterial colonies
• C. Visible dirt only
• D. Odor

Answer: (A)

ATP bioluminescence testing detects ATP, the molecule found in all living cells. The test uses a light-producing reaction that yields more light as more ATP is present, so the amount of light corresponds to how much organic material remains on a surface after cleaning. Because ATP exists in living cells, the reading reflects residual biological material—microbes as well as other organic matter—not just visible dirt, odors, or counted bacterial colonies. This is why the test is described as detecting biological residues.