E520 - Aluminium sulphate

Origin

Aluminium sulphate is an inorganic salt with the formula Al₂(SO₄)₃. It is typically encountered as the hydrate Al₂(SO₄)₃·nH₂O, where n can vary. It is produced industrially by reacting aluminium hydroxide with sulphuric acid. It can also be made from bauxite ore, clay, alunite and aluminium metal. Aluminium sulphate is a white crystalline solid that is soluble in water. It has been used for centuries in various applications, including water purification, dyeing, and papermaking.

Usage

In the food industry, aluminium sulphate is used as a firming agent, acidity regulator, and sometimes as a component of baking powders. It helps to maintain the crispness of pickled vegetables and fruits. It can also be used to adjust the pH of food products. In water treatment, it acts as a coagulant, removing impurities and suspended particles from water. It is also used in the paper industry to size paper, making it less absorbent. The amounts used in food are regulated to ensure safety.

Side Effects

While aluminium sulphate is generally considered safe in small quantities, excessive intake of aluminium can be associated with health concerns. Some studies have linked high aluminium exposure to neurotoxicity, bone problems, and potentially an increased risk of Alzheimer's disease, although the evidence is not conclusive. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) has established a tolerable weekly intake (TWI) for aluminium from all sources. Individuals with kidney problems may be more susceptible to aluminium accumulation. Regulatory bodies monitor and control the use of aluminium sulphate in food to minimize potential risks. The European Food Safety Authority (EFSA) has re-evaluated the safety of aluminium from dietary intake and concluded that exposure should be minimised.

Regulatory Status

Aluminium sulphate (E520) is permitted as a food additive in the European Union under specific conditions and maximum levels. It is also approved for use in food in other countries, including the United States, although regulations may vary. The use of aluminium sulphate is subject to ongoing review and assessment by regulatory agencies to ensure consumer safety. The levels permitted in food are set to minimize potential exposure and health risks.