Can table salt go bad? (+ 3 tips)

In this article, we will clarify your doubts on the query “Can salt go bad?”, and discuss how to store salt properly.

Can table salt go bad?

No, table salt does not go bad. Salt is considered a microbiologically stable product due to its very low moisture and, especially, water activity. In practice, water activity (Aw) is the amount of water available in food for microbial development. 

Remember that, like us, microbes claim for water to survive. Aw is expressed as an absolute value between 0 and 1. The closer to 1, the higher the amount of water accessible, and the more perishable the food is. 

Studies have established that food products with water activity lower than 0.6, which is the case of salt, are practically free of the risk of spoiling by yeasts, molds, or bacteria [1]. 

Salt is a powerful food preservative and has been used for centuries to extend the shelf life of several foods, such as vegetables, dairy products, meats, and seafood [1].

 The mechanism of inhibition of microorganisms by salt is mainly by lowering the Aw. As the water activity reduces, the number of groups of microorganisms able to grow decreases. For example, most bacteria require Aw above 0.9 to grow [1].

This protective effect occurs because salt ionizes completely in water into sodium and chloride, which attract water molecules about them through ion hydration making water unavailable for microbial growth [1].

Can I get any foodborne diseases from salt?

No, it is very unlikely that you will get any foodborne disease from salt, because it is too toxic to microorganisms, including those that cause illness. But caution is necessary. 

Recent studies have shown that several pathogenic bacteria (those causing diseases) can resist salt products and cause cross-contamination, which means that contaminated salt serves as a vehicle to transmit microbes from one food to another. 

According to the findings of Alves and others [2], cooking salt contamination with pathogenic microorganisms could occur as a result of poor hygienic practices (e.g. unwashed hands after manipulating raw chicken) and pass on to other foods prepared using that same salt (e.g. salads). 

The authors also showed that Listeria monocytogenes and Salmonella enterica survived in cooking salt for 146 and 126 days, respectively. 

Hence, in addition to good storing practices, aseptic manipulation of salt is strongly recommended to eliminate any risk of contamination.

What does reduce the shelf life of salt? And how long does salt last? 

The shelf life of salt is reduced: 1) if stored incorrectly or 2) if other ingredients are mixed with them. 

Regarding the storage conditions, salt is highly hygroscopic, which means that it easily absorbs moisture from the environment, particularly those with relative humidity above 75% [1]. 

If this happens, there will be more favorable conditions for the development of microorganisms, besides benefiting cluster formation and even the appearance of liquid fractions in your salt. 

Remember, salt itself does not go bad and if properly stored, can last indefinitely. Yet, if other ingredients are mixed into it, salt products can deteriorate over time:

• Iodine: Iodine is a micronutrient required for thyroid hormone production and has been added to salt worldwide as part of a public health program to fight against iodine-related deficiency disorders [3].

However, iodine dissipates over time. According to a study by Diosady and others [3], iodine may undergo 25%  losses after a year of storage, even if stored under adequate conditions. 

Salt brands label the shelf life of iodized salt to be around 5 years [4]. Table salt and marine salt are often found added with iodine in the market.

• Anticaking agents: anticaking agents, added to salts to prevent cluster formation, lose effectiveness over time. 

For this reason, salts added of anticaking elements are recommended to be consumed within 5 years for best quality, after which anti-caking loses its activity and clumping may occur.  

Kosher salt, plain table salt, coarse sea salt, fine sea salt, sea salt, and table salt are examples of salts that may contain this ingredient.

In case no anticaking is used, these salts can form clusters by absorbing water from the environment, losing quality through storage time, and reducing their recommended use-by date to 3 years [4]. 

Salts like Himalayan or Pink and Pickling/Brining salt do not have any iodine or anticaking additive, so they can become caked over time. Because of this, several brands label 3 years as their shelf life [4]. 

Nevertheless, if stored correctly Himalayan or Pink and Pickling/Brining salts can last endlessly.

• Seasoning/flavoring/spices: often, salt is found mixed with other ingredients, such as herbs and spices. 

These composed products last less than salt alone because the flavoring ingredients lose aroma and color compounds during storage, reducing their quality. Depending on the mixture of ingredients, recommend use-by date is of  2-3 years [4].

How do I know which ingredients are contained in the salt I own at home?

You can easily discover which ingredients are contained in the salt you own at home by having a quick look at the label information. If in the description of “ingredients”, there is something else than just “salt”, it means that other elements are present.

 For example, common anticaking agents you might see are sodium aluminosilicate, sodium ferrocyanide, and magnesium carbonate [5]. 

You will also be able to see disclosed on the ingredients section of labels if iodine (usually added as potassium iodide, sodium iodide, and sodium iodate) is present or not. 

Herbs and spices can also be easily noticed. If your check gave positive results, be aware that this will indicate a potentially reduced shelf life of the salt product.

Can I consume old salt? How to tell if salt has gone bad?

Yes, you can consume old salt. For quality, it is best that it has been stored in a clean, dry, and airtight place, has not been unproperly manipulated, and keeps its fresh appearance, with no clumps, liquids, or strange bodies in it.

But if any of the following spoilage signs are present in your salt, you better throw it in the bin:

• Salt smells odd: Salt can easily pick up odors. If your salt smells bad and It might ruin your dish, discard it right away.

• Dead bugs in the package: If your slat package is infested with bugs, throw it away. Even If you see one bug, there are likely many other adult bugs and their eggs.

• Salt in a large and hard clump: if the salt clumps up, it is because it has been exposed to moisture. 

If the clumps are soft and break up easily when you press them with your fingers, it is probably good to use. But if the clump is hard like a rock and won’t break despite smashing it, get rid of it.

How to store salt properly? Follow these tips

•  Store it in an air-tight container or a pouch. Salt is hygroscopic, and can absorb steam, and any unwanted odors easily. 

Whether the salt is additive-free or not, it needs to be stored correctly to keep it safe.  A grinder or salt shaker will also work since It is air-tight and accommodates only a small amount of salt which will be used up quickly.

•  Keep the salt away from heat sources like direct sunlight and stovetop.

•  The rule of thumb is to store the salt in a cool, dry, and dark place away from heat and anything with a strong smell.

Conclusion

In this article, we answered the question “Can table salt go bad?”, and how to store salt properly?

Citations 

1. Man CMD. Technological functions of salt in food products. In: Kilcast D, Angus F, editors. Reducing Salt in Foods: Woodhead Publishing; 2007. p. 157-73.

2. Alves Â, Santos-Ferreira N, Magalhães R, Ferreira V, Teixeira P. From chicken to salad: Cooking salt as a potential vehicle of Salmonella spp. and Listeria monocytogenes cross-contamination. Food Control. 2022;137:108959.

3. Diosady LL, Alberti JO, Mannar MGV, FitzGerald S. Stability of Iodine in Iodized Salt Used for Correction of Iodine-Deficiency Disorders. II. Food and Nutrition Bulletin. 1998;19(3):240-50.

4. Morton salt expiration guide. Available on: https://www.mortonsalt.com/article/morton-salt-expiration-guide/

5. Kuhn T, Chytry P, Souza GMS, Bauer DV, Amaral L, Dias JF. Signature of the Himalayan salt. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms. 2020;477:150-3.