Why does salt preserve food? A look at its preservative power

Salt has been used as a preservative since ancient times, long before modern refrigeration and packaging techniques were developed. But why does salt have this powerful preservative effect on food? Let’s dive into the scientific foundations behind this phenomenon.

Water absorption: Salt is a natural desiccant, meaning it has the ability to absorb water. When added to food, it draws water out of microbial cells present in the food through a process called osmosis. By doing so, salt dehydrates and thus kills or inhibits the growth of bacteria and microorganisms that cause spoilage.
Hostile environment for microorganisms: The high concentration of salt creates a hypertonic environment that makes it difficult for many microorganisms to survive. Bacteria, yeast, and molds require specific conditions to grow, and a salty environment interferes with their metabolic processes, preventing their proliferation.
Preservation of properties: Salt not only inhibits microbial growth but also helps preserve the organoleptic properties of food, such as flavor and texture. This is why many salt-cured foods, like ham or salted cod, have unique flavor and texture characteristics.
Enzyme inhibition: Salt can slow down or stop the activity of certain enzymes present in food that cause undesirable changes. For example, it can prevent enzymatic browning, which is a reaction that darkens fruits and vegetables when they are cut.
Synergy with other preservatives: Salt is often used in combination with other preservation methods, such as drying or smoking, enhancing its effect and further extending the shelf life of food.

In conclusion, salt is not only valuable for its ability to enhance the flavor of food but also for its historical and scientific role as a preservative. Through mechanisms such as osmosis and creating a hostile environment, salt has allowed civilizations to preserve food for long periods, ensuring the availability of provisions during times of scarcity or long journeys. It is a testament to science and nature working together for the benefit of humanity.