Which of the following must be stored at 41°F or lower?

The requirement for storing items at 41°F or lower is crucial for food safety to slow the growth of harmful bacteria. Each of the items listed in the question falls under guidelines that recommend refrigeration at this temperature to ensure safe consumption.

Chicken salad from a buffet may contain perishable ingredients like poultry and mayonnaise, both of which can harbor bacteria if not stored properly. Maintaining it at 41°F or lower helps to minimize the risk of foodborne illnesses.

Heavy cream, a dairy product, is also susceptible to spoilage and should be stored in a refrigerator at or below 41°F to prevent the growth of pathogens and maintain its quality.

Cut melons are particularly noteworthy since they can be a medium for bacterial contamination once they are cut. The flesh of cut melons is exposed, making them more vulnerable to bacterial growth. Keeping them at the recommended temperature ensures they remain safe for consumption.

Since all these items require refrigeration to inhibit the growth of bacteria and ensure safe consumption, storing them at or below 41°F is mandatory, thus making the correct answer encompass all the options provided.