Which of the following methods can effectively kill bacteria in food?

Cooking food to the proper temperature is the most effective method for killing bacteria in food. When food is cooked, the heat generated raises the temperature to a level that can effectively destroy harmful microorganisms that may be present. Different types of bacteria require different temperatures to be killed, but generally, cooking foods to an internal temperature of at least 165°F (74°C) is recommended to ensure safety, particularly for poultry, leftovers, and other potentially hazardous foods.

While freezing food can slow down the growth of bacteria, it does not kill them. Some bacteria can survive freezing temperatures, only to become active again when the food is thawed. Similarly, washing food with water can remove some surface dirt and reduce the presence of certain bacteria, but it does not guarantee that all bacteria will be killed, as washing may not reach all areas and some bacteria are resilient. Storing food in the refrigerator helps slow down bacterial growth but does not kill bacteria either; it merely keeps them dormant until the food warms up again. Thus, cooking food to the appropriate temperature is the most reliable method to ensure food safety by effectively eliminating bacteria.