Final answer:
The food item that can be re-served if it has not been used by a customer is bread, especially when it is in an unopened, sanitary wrap or container. Salad, raw fish, and partially eaten sandwiches cannot be re-served due to health and safety regulations.
Step-by-step explanation:
The food item that can be re-served if it has been in possession of a customer, but not used, is A) Bread. Typically, items like packaged crackers, compliments (like butter, jelly, or creamer), and bread that remain untouched and are still in their sanitary wraps or containers can be re-served. In contrast, dishes such as salad, raw fish, and any half-eaten sandwiches cannot be re-served to another customer due to health regulations and concerns over food safety. This is particularly critical for items that are handled by people and not cooked, like sliced meat, and for unpasteurized dairy products, as they are more vulnerable to contamination and the growth of pathogens. Any perishable food that has had the opportunity to be handled or potentially contaminated should be discarded to avoid risks of foodborne illness.