Stannous chloride

Stannous chloride (tin(II) chloride) is an inorganic tin salt used as an antioxidant at very low concentrations in canned vegetables — particularly asparagus, artichokes, and certain white vegetables — to prevent the grey or dark discolouration that can occur during heat processing and storage. It achieves this by reducing oxidation reactions that would otherwise produce off-colours and off-flavours.

JECFA's ADI for stannous chloride is 2 mg per kilogram body weight per day expressed as tin, evaluated in 1965. This numerical ADI is set conservatively given that tin compounds at higher doses can cause gastrointestinal irritation. At the trace amounts used in canned vegetables, dietary exposure is well below the ADI. Tin naturally migrates into canned food from tin-plated can interiors to some extent, meaning background tin exposure from canned food is a pre-existing consideration.

Stannous chloride is approved in the EU and several other markets at tightly controlled maximum use levels. It is found almost exclusively in canned white asparagus and certain other canned vegetables. For healthy adults at typical dietary exposures there are no safety concerns. Consumers eating large quantities of specifically canned asparagus could monitor total tin intake, but at normal consumption levels E512 poses no meaningful health risk.