Sodium benzoate is a chemical that serves various industries (pharmaceutical, food and beverage, and cosmetics) because of its many functions—including preservative and medicinal. But if you are searching for the necessary information for sodium benzoate (E211) as a food preservative alone, you’ve come to the right page. This post on sodium benzoate is for the curious consumer, student, or food industry professional. Looking for a specific information on sodium benzoate? Check out the table of content below.
Lets dive right in.
Table of Contents
Sodium benzoate (E211) as a food preservative
Benzoic acid (C7H5NaO2) is an aromatic carboxylic acid. It is found naturally in a wide range of foods, especially fruits and vegetables. Berries are particularly rich in benzoic acid. Dairy products like yogurt, milk, and cheese, and aromatic spices such as cinnamon also contain it. One of its salts and derivatives—sodium benzoate— is used widely in the food industry as a food preservative.
Sodium benzoate is a product of the neutralization of benzoic acid. (See next section for the manufacturing process). Sodium benzoate is a white and odorless crystalline powder or granule, and has a sweet yet astringent taste. It is true that this preservative does not occur naturally, hence man-made.
In the food industry, E211 is the E number assigned for sodium benzoate. E numbers correspond to food additives that are used in the European Union (EU). The other salts of benzoic acid used in food preservation is potassium benzoate (E212) and calcium benzoate (E213).
Sodium benzoate has the capability to inhibit the growth of potentially harmful microorganisms. However, acidic foods are the more common applications of sodium benzoate. More specifically, sodium benzoate is a regular in acidic foods including:
- Pickles
- Salad dressings
- Condiments
- Sodas
- Jams and jellies
- Fruit juices
- Snacks
Food must have a pH of at least 4.5 to be more effective. The lower pH, the more effective sodium benzoate is in food preservation.
The big sodium benzoate business
Sodium benzoate is a huge business due largely to the main industries it serves. According to a 2016 report by Global Wire, food and beverage holds the biggest market share globally at 46.06%. Pharmaceutical comes next at 30.72%. Then, cosmetic products at 14.5%.
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Transparency Market Research says that China is the biggest producer of sodium benzoate, globally. One of the main reasons for this is the existing ban for synthetic preservatives in certain regions. The following are a few of the key players in the industry from China.
- Tengzhou Tenglong Chemical
- Foodchem International Corporation
- Wuhan Youji Industries Co., Ltd.
- A.M. Food Chemical Co. Limited
The sodium benzoate market, like the forecast, will continue to grow. This is due largely to the lifting of the prohibition against the use of it in meat products. Sodium benzoate is effective in inhibiting the growth of Listeria monocytogenes in poultry and meat. But its ability to conceal the real quality of the meat led to its banning until 2013.
The process of producing sodium benzoate
There are 3 methods of producing benzoic acid for sodium benzoate preparation.
First is the liquid-phase oxidation of toluene with molecular oxygen. The process involves high temperature and pressure. The pressure is reduced to atmospheric once the oxidation reaction is done. The product stream is then allowed to lower the temperature. Cooling the product down helps to precipitate most of the benzoic acid. Filtration further separates the precipitated benzoic acid from the product stream. Check out this patent for more on this method.
The second method is by hydrolysis of benzotrichloride, a product of toluene and chlorine, into benzoic acid. This process involves the hydrolysis of benzotrichoride at a high temperature under pressure. In Chemistry, hydrolysis is the breakdown of a compound due to reaction with water. Adding a mineral acid precipitates the benzoic acid from the solution. Filtration further separates and refines the precipitated benzoic acid. Check out this patent for more on this method.
The third and last method is producing benzoic acid from phthalic anhydride. Phthalic anhydride is a product of oxidization of naphthalene with vanadium pentoxide. This method involves introducing a mixture of phthalic anhydride vapor and water vapor into a reaction chamber, which contains a catalyst. A maintained high temperature prevents the precipitation of phthalic acid, and instead yields more benzoic acid. Filtration further separates and refines the precipitated benzoic acid. Check out this patent for more on this method.
In all of these 3 methods, benzoic acid undergoes neutralization. Neutralization is a process by which an acid (benzoic acid) and a base (sodium hydroxide) react. The product of this reaction is water and sodium benzoate. Evaporating the water isolates the sodium benzoate. Check out this Chinese patent on the process of manufacturing granular sodium benzoate.
How does sodium benzoate exactly preserve food?
Sodium benzoate is added in bulk liquids. When dissolved in water, it dissociates and forms sodium ions and benzoate ions. The benzoate ions react with proton acid, forming benzoic acid, which itself is not very soluble in water. The benzoic acid acts as the active anti-microbial agent—which interferes with microorganisms’ metabolism. In the process, the pH level of the food increases.
At this point, you may be wondering— “why not use benzoic acid then?”
Benzoic acid is used by itself as a food preservative as well. It has its own E number (E210). It is a more effective anti-microbial agent than sodium benzoate. But sodium benzoate is most often used because of its higher water solubility. Sodium benzoate is 200 times more soluble in water.
Sodium benzoate as flavor enhancer
While used mainly as a food preservative, sodium benzoate also acts as a flavor enhancer to soft drinks. It is especially a regular ingredient in Pepsi and Coca-Cola products. High-fructose corn syrup is a common replacement for real sugar in soft drink manufacturing. But the presence of sodium benzoate enhances the soft drink’s flavor.
Major regulating agencies
Sodium benzoate is one of the most widely used food additives, and is safe when used as intended. In fact, no country has banned the used of it in foods. However, the use of it is monitored and regulated. The following major regulatory organizations approve the use of sodium benzoate:
- U.S. Food and Drug Administration
The FDA specifically considers sodium benzoate as GRAS (Generally recognized as safe), provided that it is used as intended. The use of it must not exceed 0.1 % concentration by weight in food and beverage. The same amount also applies to animal food.
- European Food Safety Authority
The European Food Safety Authority or EFSA is responsible for food law enforcement in the European Union. The European agency lists sodium benzoate as an authorized food additive in Commission Regulation (EU) No 231/2012.
- Joint FAO/WHO Expert Committee on Food Additives (JECFA)
JECFA is a program by the Food and Agriculture Organization of the United Nations (FAO) and WHO. It has been evaluating food additives since 1956. The agency lists sodium benzoate as an anti-microbial preservative.
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Researches on health and safety
There are many researches that prove that sodium benzoate (E211) is safe to use as a food preservative. Of course, provided that it does not exceed the allowable limit of 0.1 %. But anyway, here are some common issues and researches regarding sodium benzoate.
Sodium benzoate intake
What is enough? What is too much sodium benzoate acid in your diet? Researches suggest that too much sodium benzoate intake may contribute to several health issues such as stress, obesity, and allergy. But are we consuming too much sodium benzoate?
In 1999, the JECFA assessed the intake of benzoates of people from nine countries. The benzoate-containing foods that people consume were expected to vary. However, 5 of these countries (Australia, France, New Zealand, United Kindom, and the USA) were found to source their benzoates mostly from soft drinks. In Finland, nearly half of benzoate intake were from it at 40%. While the Chinese sourced their benzoates largely from consuming soy sauce, unsurprisingly. The condiment was the second most important to Japanese.
The tolerable daily intake of sodium benzoate is at 5 mg/kg body weight per day. According to the FDA, it would take 180 times the amount of sodium benzoate usually present in our daily diet before health problems to occur. Furthermore, a modified daily diet consisting of foods containing the greatest amounts of sodium benzoate would still take 90 times the amount of sodium benzoate for health problems to occur.
The FDA considers sodium benzoic and benzoic as GRAS due to the fact that there is no available evidence to show that they constitute a hazard to the general public when used at levels that are now current or that expected in the future.
Formation of benzene, a carcinogen, in soft drinks
Many soft drinks manufacturers use ascorbic acid (E300) along with sodium benzoate (and potassium benzoate) in their products. But the problem is the risk of benzene formation during storage. Benzene, in large amount, is carcinogenic, it may cause cancer in humans.
This issue first came to the FDA’s attention in 1990. However, the soft drink industry told the agency that ascorbic acid and benzoate salts-containing beverages could form benzene, but in low levels. The FDA, together with the soft drink industry, performed a research to pinpoint the factors that contribute to the formation of benzene. It turned out that elevated temperature and light can stimulate benzene formation. Because of this result, soft drink companies reformulated their products to lessen or remove the formation of benzene.
As of this writing, the FDA has tested over 200 soft drinks and other beverages. Out of these samples, 9 products containing benzene salts and ascorbic acid were above 5 ppb (benzene per billion parts). 5 ppb is the maximum allowable for benzene in drinking water. The manufacturers later reformulated these products that had exceeded the limit. You may check out this study on FDA’s page.
Want to know how much benzene is in your drink? The FDA has provided the method on the determination of benzene in soft drinks and beverages.
General safety of sodium benzoate
In 2016, the EFSA wrote a scientific opinion re-evaluating benzoic acid and its salts, sodium benzoate, potassium benzoate, and calcium benzoate as food additives. The publication was in response to the request made by the European Commission.
Based on studies, it found that benzoic acid, and its sodium and potassium salts are easily absorbed after oral administration. The results of short-term and subchronic studies suggest that the toxicity of benzoic acid and sodium benzoate is low. In terms of genotoxicity and carcinogenicity, the panel did not see any reason for concern with these food additives. The JECFA reviewed the long-term studies of benzoic acid and sodium benzoate in terms of chronic toxicity carcinogenicity in 1996.
In terms of reproductive toxicity, the panel based on a four-generation reproductive toxicity study in which it featured benzoic acid in the diet of rats. The said study resulted in no observed adverse effect level (NOAEL) of 500 mg benzoic acid/kg body weight per day.
Key takeaways
- Sodium benzoate is the sodium salt of benzoic acid
- Sodium benzoate is the product of neutralization of benzoic acid with sodium hydroxide
- It works as a food preservative by inhibiting the growth of spoilage microorganisms
- Ideal for acidic foods like jams, jellies, fruit juices, and sodas
- The lower pH, the more effective sodium benzoate is in preservation
- Benzoic acid is a more powerful anti-microbial agent
- But sodium benzoate is more often used because of its higher water solubility
- The use of sodium benzoate as a food preservative must not exceed 0.1 % by weight
- The tolerable daily intake of sodium benzoate is at 5 mg/kg body weight per day
- Major regulating agencies consider sodium benzoate (E211) as food preservative safe
So there we have it—sodium benzoate (E211) as a food preservative. Did we miss something? Or perhaps you would like to share something about sodium benzoate. Either way, share it by leaving a comment below 🙂
are there ratios for how much to use depending on foods PH levels
Hi patrick! Sodium benzoate works best for low pH food, ideally those with pH of 3.0. Here is the % benzoic acid active at certain pH levels.
pH % of active benzoic acid
3.0 = 94.0
4.0 = 61.0
5.0 = 13.7
6.0 = 1.55
7.0 = 0.0
Hope that answers your question 🙂