Which statement about Listeria monocytogenes growth is true?

• A. It cannot grow at refrigeration temperatures.
• B. It grows only at temperatures above 25 C.
• C. It can grow at refrigeration temperatures of 4 C.
• D. It requires high humidity to grow.

Answer: (C)

Listeria monocytogenes is a psychrotrophic bacterium, meaning it can grow at refrigeration temperatures. Because of this, it can multiply in foods kept in the fridge, even at about 4°C, which is why chilled, ready-to-eat products are a particular concern for Listeria safety. It can grow over a broad temperature range—from near freezing up to about 45°C—with its growth being more rapid around body temperature. Humidity isn’t a strict requirement for its growth, so it doesn’t rely on high humidity to thrive. Given these traits, the statement that it can grow at refrigeration temperatures of 4°C is true.