In addition to the refrigerator, commonly used freezing methods include the following:

1. Refrigerator freezer bag: The inner layer of this bag is frozen yogurt liquid rich in condensation agent. Can help maintain the freshness and taste of food.

2. Freezer or incubator freezing: Place the food to be frozen in an incubator or freezer, and use dry ice and other condensing agents to freeze the food.

3. Ambient temperature freezing: Usually only suitable for colder areas. Place food outdoors or in a lower temperature place such as a basement to allow the food to condense naturally.

4. Freeze with cold water: Place the food in a container filled with cold water, and then place the container in the refrigerator or freezer. This method is more suitable for small portions of food, such as meatballs.

5. Vacuum packaging and freezing: Use a vacuum packaging machine to place food or sundries into plastic bags, then seal and freeze them.

In short, in addition to the refrigerator, there are many ways to freeze food. You should choose the most appropriate method according to different situations.