Why does salt preserve food? (3 reasons)

In this brief guide, we are going to answer the question “Why does salt preserve food” with an in-depth analysis of the characteristics that makes salt a good preservative. 

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

Why does salt preserve food?

Salt functions as a potent preservative by lowering the water activity within foods. The term “water activity” refers to the quantity of free water accessible for both microbial proliferation and chemical transformations.

Salt achieves this water activity reduction through the capacity of sodium and chloride ions to form connections with water molecules. Before refrigeration, salt stood out as a primary technique for impeding the proliferation and endurance of unwanted microorganisms.

While contemporary strides in food preservation, packaging methodologies, and swift transportation have largely diminished this function, salt continues to be used to prevent swift spoilage, consequently extending the longevity of products.

Additionally, salt creates an environment that is unwelcoming to pathogens while fostering the growth of beneficial microorganisms within diverse fermented foods and other merchandise. (1)

What is the basis of food preservation?

The preservation of food encompasses a range of processing stages aimed at upholding the desired level of food quality, thereby enabling the attainment of optimal benefits and nutritional value.

These methods encompass activities such as cultivation, harvesting, processing, packaging, and the distribution of food items.

The principal goals of food preservation encompass mitigating inadequacies in agricultural planning, generating value-enhanced goods, and offering dietary diversity. (2) 

How does salt inhibit bacterial growth?

In addition to reducing water activity, the introduction of salt to food can trigger osmotic shock within microbial cells. This phenomenon leads to the expulsion of water from the cells, resulting in their demise or slowed growth.

Furthermore, there’s speculation that salt might impede the solubility of oxygen for certain microorganisms, disrupt cellular enzymes, or compel cells to expend energy to repel sodium ions. These actions collectively contribute to a decreased growth rate.

Consequently, salt remains a prevalent agent, effectively establishing an environment that thwarts spoilage and renders it unfavorable for the persistence of harmful microorganisms within food products. (1)

What is salt’s role in fermentation to preserve foods? 

Salt holds a central role in the fermentation process of foods, a widely employed technique for food preservation. During fermentation, fresh foods transform thanks to specific types of microbes.

This transformation allows these foods to be stored for extended periods. Salt plays a crucial role in this process by encouraging the proliferation of salt-tolerant, beneficial microorganisms while concurrently hindering the development of unwanted spoilage bacteria and fungi naturally found in these foods.

Additionally, salt contributes to the withdrawal of water and sugars from plant tissues during the fermentation of vegetables. This water plays a pivotal role by occupying air pockets present within fermentation containers, leading to an oxygen-restricted environment that fosters the growth of lactic acid bacteria.

The release of water and sugars also stimulates fermentation reactions within the resulting brine, consequently expediting the overall fermentation process. (1) 

What are the alternatives to salt for preservation?

Conventional alternative methods of food preservation, include dehydration, freezing, refrigeration, pasteurization, and chemical treatments. These methods are extensively employed globally. Ongoing scientific advancements are catalyzing the refinement of existing technologies and the creation of novel ones, such as irradiation, high-pressure methods, and hurdle technology.

The field of food preservation has evolved into a profoundly interdisciplinary realm, encompassing stages spanning cultivation, harvesting, processing, packaging, and distribution. Consequently, an integrated approach proves beneficial for effectively preserving food items throughout the various stages of production and processing. (2)

What other roles salt plays in food?

Besides its uses for preservation, salt holds a significant role in the domain of food processing. Its applications are broad and varied, encompassing everything from basic flavor enhancement to multifaceted functional contributions across diverse food systems.

In natural cheeses, salt assumes multiple functions: it curbs the growth of undesirable bacteria, ensures the prevalence of desired microbial cultures, moderates the pace of lactic acid fermentation, and contributes to the favorable development of flavor, texture, and body.

Additionally, it imparts a distinctive salty taste. Within processed meats, salt interacts with specific muscle proteins, facilitating the formation of stable emulsions that bind moisture and fat. Moreover, salt’s impact extends to regulating the pace of fermentation in yeast-leavened products and strengthening the gluten structure in bread dough. (3)

Does consuming food with high salt concentration have adverse effects?

Yes. Consuming an excessive amount of salt induces a rapid surge in plasma sodium concentration, reaching its peak within a few hours after ingestion. Consequently, cells experience a process of contraction due to the osmotic movement of fluid from within the cells.

The heightened sodium intake triggers an expansion in extracellular volume, resulting in elevated blood pressure. This surge in blood pressure prompts a response that encourages the elimination of both sodium and water from the body through urine.

The act of overconsuming salt can give rise to an array of undesirable effects, including inflammation of microvascular endothelial cells, structural alterations in blood vessels, and functional irregularities in their operation. (4-6)

FAQs about Salt which you may be interested in.

Why does salt draw out water?


In this brief guide, we answered the question “Why does salt preserve food” with an in-depth analysis of the characteristics that makes salt a good preservative. 


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Institute of Medicine (US) Committee on Strategies to Reduce Sodium Intake; Henney JE, Taylor CL, Boon CS,  4, Preservation and Physical Property Roles of Sodium in Foods. Strategies to Reduce Sodium Intake in the United States. Washington (DC): National Academies Press (US); 2010.


Amit, S.K., Uddin, M.M., Rahman, R. et al. A review on mechanisms and commercial aspects of food preservation and processing. Agric & Food Secur 6, 51. 2017.


Reddy, K. A., & Marth, E. H. Reducing the Sodium Content of Foods: A Review. Journal of Food Protection, 54(2), 138–150. 1991.


Metheny, N. A., & Krieger, M. M.  Salt Toxicity: A Systematic Review and Case Reports. Journal of Emergency Nursing. 2020.


Agócs R, Sugár D, Szabó AJ. Is too much salt harmful? Yes. Pediatr Nephrol.35 (9) :1777-1785. 2020.


Grillo A, Salvi L, Coruzzi P, Salvi P, Parati G. Sodium Intake and Hypertension. Nutrients. 11(9):1970. 2019.