Final answer:
To protect the health of elderly residents in a nursing home, the food manager should serve pasteurized dairy products which are safe to consume, unlike raw seafood, undercooked meat, or unwashed vegetables that can harbor harmful bacteria.
Step-by-step explanation:
A nursing home food manager best protects the elderly residents' health by serving pasteurized dairy products. Serving raw seafood, undercooked meat, or unwashed vegetables exposes residents to harmful bacteria such as Salmonella, E. coli, Listeria, and Vibrio, which are prevalent in these types of foods. These bacteria can cause serious foodborne illnesses, which are particularly dangerous for the elderly due to their weakened immune systems. Pasteurization is a process that kills these harmful microorganisms, making dairy products safe to consume. Therefore, it is crucial to serve pasteurized dairy products in a nursing home to prevent health risks associated with bacterial infections.