Sodium Metabisulfite (E223)

Purpose and Function

Sodium metabisulfite is a widely used food additive with various functions, primarily as a preservative and antioxidant. It helps to extend the shelf life of foods by inhibiting the growth of harmful microorganisms and preventing oxidation.

• Preservative: It is used to prevent the spoilage of food products by controlling the growth of bacteria, yeast, and mold. It is especially effective in processed foods, dried fruits, and beverages like wine and beer.
• Antioxidant: The additive helps prevent oxidation, which can cause food discoloration and nutrient degradation. This is particularly important in preventing enzymatic browning in foods like dried fruits and potato products.
• Anti-caking Agent: Sodium metabisulfite is also used in powdered foods to prevent clumping and ensure smooth flow, particularly in starches and spices.
• Wine and Beverage Stabilizer: In winemaking, sodium metabisulfite is used to sterilize equipment and kill off unwanted bacteria and yeast in wine production. It also preserves the flavor and color of beverages like beer and soft drinks.

Potential Risks and Side Effects

Sodium metabisulfite is generally recognized as safe by food regulatory authorities, but it can pose certain risks, particularly for individuals with sensitivities:

• Allergic Reactions: Some individuals, particularly those with asthma, may experience allergic reactions to sodium metabisulfite. These reactions can include symptoms such as wheezing, shortness of breath, and other respiratory issues. Asthmatics are particularly vulnerable to sulfite sensitivity.
• Gastrointestinal Issues: Some studies suggest that high levels of sodium metabisulfite consumption may lead to digestive problems such as stomach cramps, nausea, and diarrhea.
• Skin Irritation: Sodium metabisulfite has been known to cause skin irritation, particularly when handled in large quantities in its powdered form, which can lead to allergic dermatitis in sensitive individuals.
• Potential Toxicity: At very high concentrations, sodium metabisulfite can release sulfur dioxide, which may cause respiratory irritation and long-term health effects if inhaled. However, the levels used in food products are typically far below the harmful threshold.

A 2015 study indicated that sodium metabisulfite could have pro-inflammatory effects in certain people, especially those who are sulfite-sensitive . However, the exact risks remain under study, and most people do not experience negative effects from typical food concentrations.