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Salt, food preservation & taste

In addition to improving taste, salt plays an important part in preservation and food safety. According to experts in food science, sodium is important for preservation and to prevent food spoilage particularly in food categories like deli-meats. Deli-meats account for 9% of dietary sodium in the Canadian diet. Some experiments with educed sodium deli-meats resulted in food spoilage. The food Industry is currently working on alternate preservation methods, such as salt substitutes and high pressure packaging in an effort to reduce salt in these categories. Salt reduction in some categories could result in a shorter shelf life for those products.

Research is also currently underway on lower sodium bread products.


According to the Sodium Working Group Report:

While most sodium added to foods is in the form of salt, there are a number of other sodium-based food additives and ingredients, as well as some naturally occurring sodium in foods. The process of reducing the sodium content of foods is complex since the role and function of salt and other sodium based ingredients in foods varies, depending on the nature of the food. Salt is used as flavouring, a preservative and an antibacterial agent; it also has many effects on the texture and structure of foods. These functions have impacts on the food, many of which are perceptible by consumers. Changes to the salt content are often detectable, although consumers may not attribute the changes to alterations in sodium levels.

Many factors can affect microbial growth in foods and they most often work in concert to inhibit or prevent bacterial growth. The use of factors such as temperature, pH, water activity (or available water), antimicrobial food additives or ingredients, presence of salts (including sodium chloride), oxygen and microbial load and competition must be examined by food processors in order to ascertain the right balance for the manufacture of safe foods. In general, more than one, and potentially all of these are used in preventing microbial growth that might otherwise cause foodborne illnesses. Salt (NaCl) works as an effective preservative due to its ability to induce cell dehydration and through other mechanisms; most bacteria are susceptible to high
levels of salt. 63 However, there are bacteria and fungi with varying degrees of tolerance to salt ranging from salt resistant and salt tolerant to halophilic ("salt-loving"). Examples of food borne bacterial pathogens that are salt tolerant, salt resistant, and halophilic, respectively, are Listeria monocytogenes, Staphylococcus aureus, and Vibrio parahaemolyticus. Nevertheless, salt and other sodium compounds can play an important role in preventing the growth of pathogenic
bacteria {including Clostridium botulinum} and spoilage microorganisms. Therefore, changes to formulations to reduce sodium content must be well-researched to ensure microbial safety is not jeopardized"

HOWEVER, in many food categories, higher levels of salt are primarily present for flavor and to maintain texture. Research also suggests that consumer palates gradually adjust to lower salt levels.

 

According to Dr. Andrew Pipe, expert in cardiovascular disease prevention:

"..In terms of conversations I've had with my patients in a clinical setting, where individuals who have changed their sodium intake, they no longer use the salt shaker, and they are fastidious in terms of reading food labels and the food purchases the make, they say that within a few weeks, they can't believe how salty food that they'd previously added even more salt to, tastes. I think our taste buds do accommodate and probably more rapidly than most people think. "

 

From the Sodium Working Group report: 

Taste is adaptable Despite potential perceptions about taste of sodium-reduced foods, taste does not have to be a deterrent. It is well established that people adapt quickly to changing salt levels in food. Once familiar with the taste of lower salt foods, they typically perceive salty foods as being unpleasant. The report from the 2006 WHO Technical Meeting on reducing salt intake, as well as many other references, make special note of this tendency to adapt. The Australian Sodium in Bread Study found that participants were unable to detect incremental reductions in sodium content. A 25% reduction over a six-week period in the amount of sodium included in bread was not noticed by subjects and did not affect their assessment of the flavour or preference for the product. A 2008 follow-up project to the China Salt Substitute Study found that gradual salt substitution did not appreciably affect taste or acceptability of foods. McCain Foods has conducted preliminary research that shows consumers cannot detect a gradual decrease in sodium levels in certain food products.

Click here for more information on the food industry association position.