How to protect food from bacteria?

In practice, we cannot do this, since it requires a lot of devices. For example – store food under ultraviolet light. Many bacteria can survive after heat treatment, and pasteurization with your own hands is not always carried out correctly, and this also requires special devices. We do not protect food from bacteria, we slow down the process of their reproduction on food. This is the heat treatment and storage of food in sealed trays in the refrigerator or freezer.