ALLERGENICITY OF GOURMET NUT OILS PROCESSED BY DIFFERENT METHODS

Background: No information is available on allergenicity of tree nut o ils, and information oil peanut oils has been conflicting. Many of the nut oils now on tile market undergo minimal processing and mag contai n residual antigen. Objective: This study was carried out to determine whether several of the new ''gourmet'' tree nut oils, as well as pean ut oils, contain residual proteins that could bind IgE from sera of pa tients with allergy. Methods: Several brands of walnut, almond, hazeln ut, pistachio, and macadamia nut oils were examined, Peanut oils, both unrefined oils (which have been shown to contain allergenic proteins) and refined oils (without previously demonstrable allergens), were al so examined to confirm reproducibility of immunoreactivity as reported by other investigators. Oils were extracted with O.2 mol/L ammonium b icarbonate, and protein concentrations in the aqueous extracts were me asured, IgE binding was assayed by slot-blot and Western immunoblottin g. Pooled sera from patients with a history of systemic reactions to v arious tree nuts or peanuts were used as appropriate. Results: The oil extracts known to be from oils that had undergone less processing at lower temperatures tended to demonstrate qualitatively greater IgE bin ding and higher protein concentrations. Conclusion: Tree nut and peanu t oils may pose a threat to patients with allergy, depending on the me thod of manufacture and processing.