How does salt kill bacteria?

In this brief guide, we are going to answer the question “how does salt kill bacteria” with an in-depth analysis of the mechanisms by which salt kills bacteria. Moreover, we are going to discuss how salt can be used to preserve food.

So without much ado, let’s dive in and figure out more about it.

How does salt kill bacteria?

Salt kills the bacteria by sucking water out of them. Moreover, it can also alter the internal machinery of bacteria and microbes, thereby killing them.

Salt is very toxic and harmful to bacteria. In a hypertonic solution owing to the process of osmosis and plasmolysis, the water will move out of the bacterial cells, thereby shrinking and killing them. 

The bacterial cells lose all of their water in the following manner, first, the bacterial cell dehydrates resulting in the loss of the cell’s structure. This causes enzyme and protein dysfunction and eventually results in bacterial cell death.

Moreover salt can also be harmful to the internal machinery like the DNA of the bacteria, therefore salt can kill the bacteria, thereby protecting the food from the bacteria and preserving it for a long time.

One of the examples is Salt Cured Meat.

What is osmosis?

Osmosis is the process by which a solvent moves from a low solute concentration point to a high solute concentration point. Osmosis maintains the solute-solvent balance across semi-permeable membranes, and it also plays a crucial role in the body of living organisms.

What is plasmolysis?

Plasmolysis is a process that takes place because of osmosis. In plasmolysis, the cell loses its water content when it is placed in a hypertonic solution (the solution having a high solute concentration). As the cell loses its water content, it shrinks.

Can bacteria tolerate salty conditions?

Some bacteria can tolerate salty conditions and are known as halotolerant.

Does salt kill bacteria in the mouth?

Some bacteria in the mouth and throat can be killed by saltwater, but not all. However, what salt solutions do is that they can bring bacteria to the surface of the gums, teeth, and throat. When germs reach the surface, some of it is washed away when a person spits saltwater out.

What is a saltwater gargle?

A saltwater gargle is an effective home cure for sore throats and other causes of mouth and throat pain, it alleviates mouth and throat pain. 

Saltwater solutions, which are simply a mixture of water and table salt, might be a low-cost, safe, and effective alternative to medicated mouthwashes.

What are the alternatives to saltwater gargle?

Alum can be used as an alternative to saltwater gargle. The saltwater gargle is not as effective as the alum mouthwash at reducing bacteria. Some medicinal mouthwashes contain the active component alum, which is potassium aluminum sulfate.

Can salt be used to preserve food?

Yes, salt can be used to preserve food. Salt has the property to draw water out of the food and resultantly not only make it dry but also kills the bacteria that had previously found their way to that food item. Owing to this property of salt, it is used as a preservative to store and preserve different food items.

How does salt preserve food?

In the case of meat, what we do is, apply salt in a generous amount to the meat and leave it. After some time the salt draws out the water from the meat, thereby making it dry.

So, after applying salt to the meat, the outside of the meat becomes hypertonic, with a larger concentration of salt present on the surface as compared to inside the meat’s cells. As a result, water tends to flow from a site of lower solute concentration (meat cells) to a point of higher solute concentration (outside the meat). As a result, salt draws water from various food products.

The same is true for vegetables, where the addition of salt causes the surrounding environment to become hypertonic, drawing water out of the veggies and making them saggy and overly softened.

Now, as we all know that bacteria and microbes need moisture and a particular temperature to grow on the meat. So the meat that is devoid of its moisture won’t provide a suitable environment for the microbes to grow onto. Therefore the bacterial growth will be halted and the meat that has been cured lasts for a very long time.

Moreover salt also helps in the process of fermentation that considerably increases the shelf life of foods. 

You can read Can you use salt as a disinfectant here.


In this brief guide, we answered the question “how does salt kill bacteria” with an in-depth analysis of the mechanisms by which salt kills bacteria. Moreover, we discussed how salt can be used to preserve food.


Mahnoor Asghar is a Clinical Nutritionist with a bachelor's degree in Nutrition and Dietetics. She is compassionate and dedicated to playing her part in the well-being of the masses. She wants to play a fruitful role in creating nutrition and health-related awareness among the general public. Additionally, she has a keen eye for detail and loves to create content related to food, nutrition, health, and wellness.