Which preservation technique involves heating food to mild temperatures and then cooling them immediately?

The preservation technique you're describing is called pasteurization.

Here's a breakdown:

* Heating to mild temperatures: This is usually done at temperatures between 145-161°F (63-72°C) for a set amount of time. This is enough to kill most harmful bacteria that can cause spoilage and disease.

* Cooling immediately: This step helps prevent the food from being cooked further and ensures that the desired texture and flavor are retained.

Pasteurization is a common method for preserving a variety of foods, including:

* Milk

* Juice

* Wine

* Beer

* Eggs

Let me know if you'd like to know more about pasteurization!