Question

Which of the following enzymes are used in the monitoring of hygiene status of dairy equipment surfaces by luminescence based method?

• A. Luciferase & Apyrase
• B. Luciferase & Lipases
• C. Apyrase & Proteinases
• D. Lipases & Proteinases

Hint:

In ATP hygiene monitoring:
- Apyrase removes background (non-microbial) ATP.
- Luciferase generates the light signal proportional to microbial contamination.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
ATP bioluminescence is a rapid method used to monitor the hygiene status of food contact surfaces by detecting residual Adenosine Triphosphate (ATP) from organic soils and microbial cells.

Step 2: Detailed Explanation:
The assay chemistry relies on a highly coordinated enzymatic reaction:
- Luciferase: This enzyme catalyzes the oxidation of luciferin in the presence of ATP and oxygen, releasing light (luminescence) that is directly proportional to the amount of ATP present:
\[ \text{ATP} + \text{Luciferin} + \text{O}_2 \xrightarrow{\text{Luciferase}} \text{AMP} + \text{PPi} + \text{Oxyluciferin} + \text{Light} \]
- Apyrase: To ensure that the test specifically measures microbial ATP rather than free extracellular ATP from non-microbial somatic milk residues, the enzyme apyrase is added first. Apyrase selectively degrades any free somatic ATP on the swab.
- After this pre-treatment, the microbial cells are lysed to release their intracellular ATP, which is then measured using the luciferase reaction.

Step 3: Final Answer
The enzymes used in this bioluminescence monitoring method are luciferase and apyrase.