Which of the following is NOT listed as a common source of Listeria monocytogenes?

• A. Dairy
• B. Processed meats
• C. Seafood
• D. Vegetables

Answer: (C)

Listeria monocytogenes is a pathogen that poses the greatest risk in foods that are stored refrigerated and often eaten without further cooking. Because it can grow at fridge temperatures and survive for long periods, foods that are ready-to-eat and have extended shelf life are the main concerns.

Dairy products are a classic high-risk category, especially unpasteurized milk and soft cheeses, where contamination can persist through processing and storage. Processed meats and deli products are another major source because they are ready-to-eat and regularly kept in the cold chain, sometimes with insufficient cooking to inactivate the organism. Vegetables, including ready-to-eat produce, also appear on common lists due to contamination from soil, water, or handling, and because they are often consumed raw.

Seafood is not typically listed as a leading common source in standard risk profiles, even though contamination can occur. It is less frequently highlighted as a primary vehicle for Listeria outbreaks compared with dairy, processed meats, and vegetables. Therefore, seafood is the one that is not commonly listed as a primary source.