Which organism is associated with gastroenteritis from unpasteurized dairy products and ready-to-eat deli meats?

• A. Escherichia coli O157:H7
• B. Campylobacter jejuni
• C. Salmonella enterica
• D. Listeria monocytogenes

Answer: (D)

Listeria monocytogenes is classically linked to gastroenteritis from foods that can be stored refrigerated and are served ready-to-eat, including unpasteurized dairy products and deli meats. Its key trait is the ability to grow at low temperatures, meaning it can survive and even multiply in the fridge on ready-to-eat meats and soft cheeses made from unpasteurized milk. This makes contamination in those foods a well-known route for illness. In healthy people the illness may be mild gastroenteritis, but in pregnant women, newborns, the elderly, or immunocompromised individuals it can be much more serious.

By contrast, the other organisms are typically associated with different food sources: E. coli O157:H7 with undercooked ground beef and certain raw produce; Campylobacter with undercooked poultry and, sometimes, unpasteurized dairy; Salmonella with eggs, poultry, and various contaminated foods.