Listeria monocytogenes is notable for which trait?

• A. Grows in the cold, high fatality rates
• B. Only survives at high temperatures
• C. Is non-pathogenic
• D. Is primarily a plant pathogen

Answer: (A)

This item centers on a striking trait of Listeria monocytogenes: its ability to grow at refrigeration temperatures. Listeria is psychrotrophic, meaning it can multiply in cold environments like the inside of a refrigerator, even at around 4°C. That capability allows contaminated ready-to-eat foods to stay safe-looking while the bacteria continue to grow, which is a key reason why this organism is a major food-safety concern. Coupled with its potential to cause listeriosis, which can be severe and even fatal, especially for pregnant people, newborns, older adults, and immunocompromised individuals, the combination of cold growth and high mortality makes this trait particularly notable.

The other statements don’t fit because Listeria does not only survive at high temperatures; in fact, it grows well at low temperatures too. It is pathogenic, not non-pathogenic, and it is not primarily a plant pathogen.