Which of the following is not a method of food preservation?

Food preservation refers to the processes and techniques used to keep food from spoiling and to extend its shelf life. Food can't be entirely sterilized by boiling it in water. At temperatures of 100°C or above, only bacteria, yeasts, and molds can be destroyed. Furthermore, it does not keep the food fresh. Salting, drying, freezing, and pickling are the most frequent food preservation procedures. The preservation of food using dry edible salt is known as salting.

 Food drying, also known as dehydrating, is a method of preserving food by removing enough moisture from it to prevent bacteria, yeast, and molds from growing. 

Pickling is the process of soaking and storing food in a salt solution, vinegar, or a combination of both.