No abstract

Hidden allergens are a common problem in food safety that has been known for many years. This is why the European Parliament adopted Directive 2003/89/EC amending 2000/13/EC. In addition to specific ingredients, Directive 2003/89/EC also requests the declaration of specific products that were used in the production and could be a risk for allergic individuals. This also includes the declaration of fining agents and lysozyme used in wines. In fact, it could be assumed that fining agents would be almost completely removed during the manufacturing process; however, until now there has been no necessity to analyze wine for these fining agents. By applying enzyme-linked immunosorbent assay (ELISA), residuals of fining agent proteins and the stabilizer lysozyme were investigated in various German wines. The results showed no detectable amounts of fining agents in wines, except for dried egg white and lysozyme, both derived from hen's egg white. For those products, adverse reactions against treated wines could not be excluded.

Lysozyme used in wine production could present a risk for consumers allergic to hen's egg. Thus, precautionary labeling of lysozyme on wines has been adopted within the European Community by updating Annex IIIa by Directive 2007/68/EC on November 27, 2007. Since no scientific data is known about the actual amounts and risks of lysozyme in wines, various in vitro efforts and skin prick tests were applied in this study to evaluate the presence of lysozyme in wines and the reactivity of those residues in allergic individuals and to fulfill the claim of updating Annex IIIa announced in Directive 2003/89/EC. Depending on the wine's color (red or white wine) and fining with bentonite, which is known as an important step to remove unstable proteins mainly from white wines, diverse results were obtained concerning the amounts of lysozyme in finished wines and their in vitro and in vivo reactivity in humans allergic to hen's egg.

Sera of 11 patients were used to characterize allergens in kiwi fruit, latex, avocado, and banana by SDS-PAGE/immunoblotting and to determine cross-reactions between these allergen extracts in EAST inhibition and immunoblot inhibition. By SDS-PAGE/immunoblotting, allergens with apparent molecular weights of 21, 38, 40, and 42 kDa were visualized in latex extract. In avocado extract, IgE-binding components of 27, 43, 52, 58, 65, 75, and 88 kDa were to be seen, whereas, in banana extract, a 40-kDa protein showed strong IgE binding. Furthermore, allergens of 52, 58, 88, and 94 kDa were detected in the extract of banana. Cross-reactions between these allergen extracts were determined by EAST inhibition. Immunoblot inhibition demonstrated that almost all IgE-reactive bands in nitrocellulose-blotted latex, avocado, and banana extracts and two components of 43 and 67 kDa in kiwi fruit shared common IgE epitopes.

The sera of 29 patients who suffered from pollen-related food hypersensitivities and complained of allergic reactions to kiwi fruit and other tropical fruits were tested for specific IgE antibodies against kiwi fruit, apple, carrot, celery and birch pollen using an enzyme allergosorbent test (EAST). In 20 sera, specific IgE antibodies were detected against all five extracts. Sodium dodecyl sulphate polyacrylamide gel electrophoresis/ immunoblot of kiwi fruit extract revealed two major allergens with molecular weights of approximately 43 and 67 kDa. In EAST inhibition assays, cross-reactivities between kiwi fruit, apple, birch pollen and, to a lesser degree, carrot and celery were demonstrated. The cross-reactivities seen between kiwi fruit, birch pollen and apple were not caused by the major allergen of birch pollen (Bet v 1). Allergens with molecular weights of approximately 68 kDa in birch pollen and 67 kDa in apple cross-reacted with the allergens of kiwi fruit, as demonstrated by immunoblotinhibition. Profilins, which are known plant pan-allergens, do not seem to be relevant allergens in kiwi fruit.