Allergenicity of wine containing processing aids: A double-blind, placebo-controlled food challenge

Background: The European Union requires allergenic food ingredients to appear on labels in order to protect allergic consumers. Objective: To determine whether traces of egg-, milk-, and fish-derived processing aids used in winemaking might elicit clinical reactions in food-allergic patients. Methods: Five German wines were fined with a high dose of egg albumin, lysozyme, milk casein, fish gelatin, or isinglass, and filtered. Fourteen adults with allergy to egg (n=5), milk (n=5), or fish (n=4) were included. Skin prick tests were performed with fining agents, and fined and unfined wines. All patients underwent double-blind placebo-controlled food challenges with fined and unfined wines. Results: Skin prick tests were positive to hen's egg (n=5), ovalbumin (n=5), lysozyme (n=4), cow's milk (n=5), casein (n=4), and cod (n=3), but not to isinglass or fish gelatin (n=0). Positive skin prick test results were observed for wines fined with albumin (n=3), lysozyme (n=2), casein (n=1), gelatin (n=0), and isinglass (n=3), and for unfined wines (n=1-2 in each patient group), with no significant differences between groups. Seventy-five percent of skin test-positive patients had specific immunoglobulin E to other allergens present in wine (eg, carbohydrates). The provocation test revealed no reactions to fined or unfined wines. Conclusions: Although concentrated fining agents containing ovalbumin, lysozyme, and casein were allergenic in the skin prick test, no patient reacted adversely in the provocation test to fined wine. Wines treated with fining agents at commercial concentrations appear not to present a risk to allergic individuals when filtered.