What is the most commonly used food preservative?

The most commonly used food preservative is salt (sodium chloride). It has been used for centuries to preserve food by inhibiting the growth of microorganisms. Salt works by drawing water out of bacteria and other microorganisms, which prevents them from growing. It also inhibits the production of enzymes that are necessary for microbial growth. Salt is used to preserve a wide variety of foods, including meat, fish, vegetables, and cheese.