For how many hours must a ham sandwich prepared by a caterer be discarded?

The correct answer is based on food safety guidelines regarding the safe holding and service temperatures of perishable foods. A ham sandwich, being a potentially hazardous food item, must be discarded if it has been left at room temperature for more than 4 hours. This duration is aligned with the guidelines set forth by the Food and Drug Administration (FDA), which states that foods not kept at safe temperatures (either below 41°F or above 135°F) should not be kept for more than 4 hours in order to prevent the growth of harmful bacteria.

This time frame is critical in ensuring the safety of ready-to-eat foods, especially those involving meats and dairy products, which can support quick bacterial growth if not handled correctly. Something left out beyond this limit poses a risk to consumers, making it essential for caterers and food handlers to adhere to these recommendations.