Fining-Derived Allergens in Wine: from Detection to Quantification

Abstract

Since 2012, EU Commission approved compulsory labeling of wines treated with allergenic additives or processing aids “if their presence can be detected in the final product” (EU Commission Implementing Regulation No. 579/2012 of 29 June 2012). The list of potential allergens to be indicated on wine labels comprises sulphur dioxide and milk- and egg- derived fining agents, including hen egg lysozyme, which is usually added in wines as preservative. In some non-EU countries, the list includes gluten, tree nuts and fish gelatins. With the exception of lysozyme, all these fining proteins were long thought to be totally removed by subsequent winemaking processings (e.g. bentonite addition). Suitable methods to detect and quantify potential residual allergens are necessary to ensure compliance with legislation. ELISA kits are routinely used to ensure the absence of allergenic proteins in wines, since they are easy to perform. The required LOD and LOQ for milk and egg products with ELISA methods are 0.25 ppm and 0.5 ppm (OIV Comex 502- 2012). In a recent paper (1), no detectable egg white protein residue was found in red wines by ELISA, even when coadiuvant was added at 660 ppm, without following bentonite treatment. In 2011, a clinical survey (2) reported that, although no allergen residue was detected by ELISA kits in the fined wines, positive skin prick test reactions and basophil activation to the treated wines were observed in the majority of patients with allergy to milk, egg or fish, correlating with the concentration of the fining agents used. From these findings, some uncentainty about the safety of wines certified as “allergen-free” through ELISA methods can exist. More recently, mass spectrometry have been proposed, mainly as a confirmatory method of results from ELISA. The two main drawbacks for MS-based methods, especially in the past, were insufficient LOD and LOQ, and high costs. At present, some methods with competitive performance and linearity have been set up for milk and egg protein based fining aids. Aim of the present presentation is to review the different approaches in the detection of allergenic residues in wines, including recent metrological approaches, and development of innovative biosensors. Preliminary data on MS-based method that is currently being developed in our laboratory will be presented, as well future perspectives on the topic and possible implications for consumers health, safety and ethical preferences.

1- Uberti F., et al. Immunochemical investigation of allergenic residues in experimental and commercially-available wines fined with egg white proteins. Food Chem. 2014;159:343-52. 2- Vassilopoulou E., et al. Risk of allergic reactions to wine, in milk, egg and fish-allergic patients. Clin Transl Allergy. 2011;1:10.