Safety assessment of the active substance potassium metabisulfite, for use in active food contact materials

This scientific opinion of the EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF) deals with the safety assessment of the active substance potassium metabisulfite, food contact material (FCM) substances No 1056, intended to extend the shelf life of wine. The active substance is sulfur dioxide (SO₂, E 220) which is generated in situ from potassium metabisulfite, E 224. Alternative precursors of SO₂ are other authorised sulfites marketed as food preservatives. A gel of agar (E 406) is used as a physical support media for the E 224 and the E 220 generated from it. This mixture is contained within plastic containers that are closed with a membrane of polyethersulfone (PES). When the precursor comes in contact with water contained in the agar gel, sulfur dioxide is formed. The PES acts as a microporous membrane which ensures the controlled diffusion of SO₂ from the active cap to the wine. Interactions and reactions between the active ingredients and the PES or the agar or the plastic caps, and any consequential release of reaction products into the wine, are not to be expected. The CEF Panel concluded that the substance potassium metabisulfite (E 224), as well as any of the other authorised ‘sulfites’ (E 221, E 222, E 223, E 226, E 227 and E 228) would not be a safety concern for the consumer if used as precursors for the release of sulfur dioxide (E 220) to wine under the conditions considered in the present opinion. The release of SO₂should not cause an exceedance of the maximum permitted levels (MPLs) for total SO₂ (free SO₂ plus combined SO₂) in wine given in Regulation (EC) No 606/2009 and Regulation (EC) No 203/2012. The conclusions and the recommendations of the EFSA Panel on Food Additives and Nutrient Sources Added to Food (ANS) Panel on the re-evaluation of sulfur dioxide and sulfites should be considered.