Other names for the additive (synonyms)
General Information
Potassium metabisulfite (food additive E224) is an additive from the sulfite group used in the food industry as a preservative and antioxidant. It helps protect products from microbial spoilage, browning, and undesirable changes in taste caused by oxygen exposure. For this reason, food additive E224 belongs to several technological categories at once — preservatives, antioxidants, and color stabilizers.
In nature, potassium metabisulfite as a finished compound is rarely found, although sulfur compounds can form during natural fermentation. For industrial purposes, additive E224 is produced synthetically. Nevertheless, its action is based on the well-known properties of sulfur dioxide, which has been used to preserve wine since ancient times.
Historically, sulfur compounds began to be widely used in winemaking to prevent spoilage and maintain clarity of the beverage. With the development of the food industry, their application expanded to other products. Over time, more stable and convenient forms were developed, including potassium metabisulfite.
The chemical formula of additive E224 is K2S2O5. It is a white or slightly yellowish crystalline powder with a characteristic sulfur odor. It dissolves well in water, forming a solution that can release sulfur dioxide. The substance is sensitive to moisture and air, so it requires airtight storage.
For the food industry, potassium metabisulfite is produced by reacting sulfur dioxide with a potassium solution. The process takes place under controlled conditions, after which the product is purified and dried into a powder form. In finished food products, it acts as a source of sulfur dioxide, providing the preservative effect.
Effects on the Body
Benefits of Additive E224
Potassium metabisulfite is not a natural nutrient for the human body and does not perform a biological function like vitamins or minerals. Its benefit lies solely in preserving product quality, which indirectly contributes to food safety. By inhibiting the growth of microorganisms and slowing oxidation, it helps prevent food spoilage.
The European Food Safety Authority in 2022 confirmed that, when consumed within established limits, sulfites including additive E224 can be used without significant health risk.
Risks of Additive E224
After ingestion, potassium metabisulfite is rapidly converted into sulfites and then oxidized to sulfates. In most people, this process occurs with the help of the enzyme sulfite oxidase, after which the compounds are excreted in urine.
However, some individuals may have increased sensitivity to sulfites. This is most often manifested as allergic reactions or bronchospasm, especially in people with bronchial asthma. EFSA notes that sulfites have a group acceptable daily intake (ADI) of 0.7 mg/kg body weight per day expressed as sulfur dioxide.
Exceeding this level may lead to gastrointestinal symptoms, headaches, or hypersensitivity reactions. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) also supports the establishment of a group ADI for sulfites. In the United States, the use of sulfites is regulated by the FDA, which requires mandatory labeling of their presence in food products.
Uses
In the food industry, additive E224 is mainly used as a preservative and antioxidant. Its most well-known application is in winemaking, where it prevents unwanted fermentation and maintains the stability of the beverage. It is also added to dried fruits to prevent browning, as well as to juices, syrups, certain confectionery products, and semi-finished foods.
A key feature of its use is strict dosage control and mandatory labeling when concentrations exceed the established threshold. This is due to the potential for sensitivity reactions in consumers.
Legal Status
In the European Union, preservative E224 is permitted in accordance with Regulation (EU) No 1333/2008 on food additives. A group ADI of 0.7 mg/kg body weight per day (expressed as sulfur dioxide) is established for sulfites.
In Ukraine, the use of potassium metabisulfite is harmonized with European regulations. In the United States, the additive is permitted by the FDA with mandatory labeling requirements. In Canada and Japan, preservative E224 is also allowed in food production within national safety standards.
In most countries worldwide, food additive E224 remains permitted provided that established consumption limits are respected.