Which is a way to prevent contamination of hot food on display in a self service area?

Instructing customers to use a clean plate each time they come to the service area.

Explanation:

Food safety is a very important matter and one that must be taken seriously when it is necessary to expose and provide food. Whenever a food will be exposed and offered, some practices must be followed that allow the food to maintain its integrity and quality without the risk of contamination, otherwise customers may develop some food infection and this may diminish the credibility of the establishment.

An example of practice that can contribute to food safety can be seen in a situation where customers are instructed to use a clean plate whenever they arrive at the service area to prevent contamination of hot foods that are on display in a self-service area.

could you go a bit more in depth with you question? it's quite hard to understand. as soon as you do that i will be glad to : )