When cleaning a food contact surface, it is critical to do so any time when?

Cleaning a food contact surface is critical any time contamination may have occurred because this helps prevent foodborne illnesses. Food contact surfaces, which include anything that comes into direct contact with food, need to be sanitized to eliminate harmful bacteria and pathogens that could lead to cross-contamination. This action is particularly important after any potential contamination event, such as spills or contact with raw foods, to ensure the safety of the food being prepared or served.

The other scenarios presented—food preparation times, the start of new employees, and when deliveries are received—do involve practices that require cleaning, but they are not as immediate for ensuring safety as responding to potential contamination. While it's important to maintain cleanliness at all stages of food handling, the immediate response to contamination is the most critical aspect for ensuring that food remains safe for consumption.