Question

What temperature range allows for the growth of Listeria monocytogenes, making it a concern in refrigerated dairy products?

• A. -5°C to 5°C
• B. 1°C to 45°C
• C. 10°C to 60°C
• D. 20°C to 80°C

Hint:

Remember that psychrotrophs like Listeria can grow at low refrigeration temperatures (\(1^{\circ}\text{C}\) to \(4^{\circ}\text{C}\)), but their overall growth range extends all the way up to mesophilic temperatures (around \(45^{\circ}\text{C}\)).

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Listeria monocytogenes is a prominent foodborne pathogen of significant concern to the dairy industry due to its psychrotrophic nature, allowing it to multiply at refrigeration temperatures.

Step 2: Detailed Explanation:
- Listeria monocytogenes has a wide growth temperature range, typically from \(1^{\circ}\text{C}\) up to \(45^{\circ}\text{C}\) (with some strains surviving down to \(-1.5^{\circ}\text{C}\)).
- Because this growth range covers standard household and commercial refrigeration temperatures (\(4^{\circ}\text{C}\) to \(8^{\circ}\text{C}\)), the bacterium can slowly multiply in refrigerated milk, cheese, and other dairy products over time.
- While option (A) (\(-5^{\circ}\text{C}\) to \(5^{\circ}\text{C}\)) highlights its cold-tolerance, it does not represent the full growth range of the organism. Options (C) and (D) represent higher temperature ranges where Listeria cannot survive or grow effectively.

Step 3: Final Answer
The temperature range that allows for the growth of Listeria monocytogenes is 1°C to 45°C.