Other names for the additive (synonyms)
General Information
Sodium sulfite (food additive E221) is a preservative from the sulfite group, used in the food industry to prevent product spoilage and maintain their color. Additive E221 also has antioxidant properties and helps extend the shelf life of many food products.
In nature, sulfites can form during fermentation processes, for example in wine. However, for use in food products, the food additive E221 is produced industrially. It is a synthetically obtained compound with precisely defined purity standards.
The history of using sulfur compounds in food dates back to ancient times, when sulfur was used to treat wine barrels and dried fruits. In the 19th century, with the development of chemistry, it became possible to obtain stable salts of sulfurous acid, including sodium sulfite. Later, this substance received the official status of food additive E221.
The chemical formula of sodium sulfite is Na2SO3. It is a white or slightly yellowish crystalline powder without a strong odor. It dissolves well in water and has reducing properties, which allows it to slow down oxidation processes. When in contact with acids, it can release sulfur dioxide.
For food industry purposes, food additive E221 is obtained by reacting sulfur dioxide with a solution of carbonate or sodium hydroxide. The product is then purified, crystallized, and dried into a powder suitable for dosing in production.
Effects on the Body
Benefit of Additive E221
Food additive E221 is not a nutrient and does not perform any physiological function in the human body. Its benefit is primarily related to protecting products from microbial spoilage and oxidation, which reduces the risk of food poisoning.
According to the scientific assessment of the European Food Safety Authority (EFSA), for sulfites, including additive E221, the group acceptable daily intake (ADI) is set at 0.7 mg/kg body weight per day, expressed as sulfur dioxide (SO₂).
In most people, sulfites are rapidly oxidized in the body to sulfates with the help of the enzyme sulfite oxidase and excreted in urine.
Risks of Additive E221
After entering the body, sodium sulfite is converted into sulfites and partially into sulfur dioxide. In healthy individuals, these compounds are effectively neutralized and excreted. However, sensitive individuals, especially those with bronchial asthma, may experience adverse reactions.
Medical literature also describes side effects such as urticaria, swelling, skin itching, and, in rare cases, anaphylactic reactions.
In contact allergy testing, positive reactions to sodium sulfite occurred in approximately 3–4% of patients tested for allergy.
EFSA notes that in some people sulfites can cause allergic manifestations or bronchospasm, which is why EU legislation requires labeling if their concentration in a product exceeds 10 mg/kg or 10 mg/L expressed as SO₂.
JECFA also established a group ADI of 0–0.7 mg/kg body weight per day (expressed as SO₂), confirming the need to control intake. Exceeding allowable levels may cause gastrointestinal symptoms, headaches, or mucous membrane irritation.
In the USA, the FDA recognizes sulfites as safe when used within established limits, but prohibits their use on fresh fruits and vegetables intended for raw consumption due to the risk of reactions in sensitive individuals.
Uses
In the food industry, food additive E221 is used as a preservative and antioxidant. It inhibits the growth of bacteria and fungi and prevents darkening of products during storage.
It is most commonly used in dried fruits, wine and other alcoholic beverages, potato-based products, canned vegetables, some sauces, and marinades.
A key aspect of its use is precise dosing, as excess can affect the product’s taste and increase the risk of adverse reactions in sensitive consumers.
Legal Status
In the European Union, food additive E221 is permitted under Regulation (EU) No 1333/2008, with established maximum levels for different food categories. EFSA confirmed the group ADI of 0.7 mg/kg body weight per day (expressed as SO₂).
In Ukraine, additive E221 is allowed with mandatory labeling if established thresholds are exceeded.
In the USA, sodium sulfite use is regulated by the FDA. It is permitted in processed foods but restricted for use on fresh fruits and vegetables.
In Canada and Japan, additive E221 is also allowed under regulatory compliance.
Thus, food additive E221 is an approved preservative in most countries worldwide, but its use is strictly controlled due to potential individual sensitivity to sulfites.