Aluminium sulphate

Aluminium sulphate is an inorganic salt formed from aluminium and sulphuric acid, used in food as a firming agent, acidity regulator, and processing aid. In food processing it can be applied as a firming agent for certain pickled and brined vegetables, where it helps maintain crispness by reacting with cell wall pectin. It has also been used historically as a leavening aid and as a flocculant in some food and water treatment operations.

JECFA last reviewed aluminium sulphate in 2006 as part of a comprehensive reassessment of aluminium-containing food additives and concluded that an ADI could not be allocated — the available data were considered insufficient to establish a safe daily intake value. This outcome was driven by broader concerns about total dietary aluminium exposure. Aluminium is not an essential element in human physiology and accumulates in the body over time; high long-term exposure has been associated with neurological effects, and vulnerable populations including individuals with kidney disease are less able to excrete it.

Aluminium sulphate is permitted in the EU for specific and highly restricted food applications, subject to maximum level controls designed to minimise aluminium exposure. The European Food Safety Authority has conducted reviews of total aluminium intake from food additives and naturally occurring sources combined, concluding that average and high-consuming European adults may approach or exceed the tolerable weekly intake (TWI) for aluminium. Consumers who wish to reduce aluminium intake from food additives should check for E520–E523 and other aluminium-containing additive codes (E541, E554–E556) on labels, particularly in heavily processed products where multiple aluminium additives might co-occur.