Two common methods of preserving food are canning and freezing. Canning involves sealing food in airtight containers and heating them to destroy microorganisms, preventing spoilage. This method allows for long-term storage of food without refrigeration. Freezing preserves food by lowering the temperature, slowing down enzymatic reactions and bacterial growth. Both methods are effective at extending the shelf life of food while retaining flavor and nutritional value, making them essential techniques in food preservation and safety.