Analysis of commercial wines by LC-MS/MS reveals the presence of residual milk and egg white allergens

Fining agents of animal origin are commonly used in winemaking process to clarify and stabilize wines and to optimize their organoleptic properties thanks to the removal of phenolic compounds that cause bitterness and astringency. Considering the potential allergenicity of proteins used as fining agents, the need of label declaration for wines treated with such compounds is compelling. However, the difficulties in detecting proteins in a wine matrix by immunological assays have given rise to a search for alternative methods that can overcome the limitations of classical approaches. Mass spectrometry (MS) has recently emerged as a powerful and sensitive technique to detect residual fining proteins in wines. In this study we show that a simple and straightforward mass spectrometric approach can be used to reliably detect egg and milk allergens in commercial bottled wines. We tested 25 different wines by liquid chromatography coupled with tandem MS (LC-MS/MS) and found proteins of animal origin in 8 samples, so demonstrating that the proposed method allows to monitor the presence of potential allergenic proteins in fined commercial wine.