Listeria monocytogenes can

• A. It requires oxygen to survive
• B. It grows only in high moisture environments
• C. It can form biofilms on food contact surfaces if not frequently cleaned
• D. It cannot survive at refrigeration temperatures

Answer: (C)

Listeria monocytogenes often persists in food environments by forming biofilms on food contact surfaces. A biofilm is a community of bacteria embedded in a slimy matrix that adheres strongly to surfaces like stainless steel or plastic. Once a biofilm is established, the cells inside are protected from many cleaning and sanitizing agents and are harder to remove. If surfaces aren’t cleaned and sanitized frequently enough, these biofilms can serve as a continuous source of contamination, making C the best choice.

Understanding why other options aren’t correct helps reinforce why biofilm formation is the driver here: Listeria is a facultative organism, so it does not require oxygen to survive, which makes A inaccurate. It does not require only high-moisture environments; it can grow across a range of moisture conditions, so B isn’t the defining trait. And Listeria can survive and even grow at refrigeration temperatures, so D is false.