Allergenicity of gourmet nut oils processed by different methods.
BACKGROUND
No information is available on allergenicity of tree nut oils, and information on peanut oils has been conflicting. Many of the nut oils now on the market undergo minimal processing and may contain residual antigen.


OBJECTIVE
This study was carried out to determine whether several of the new "gourmet" tree nut oils, as well as peanut oils, contain residual proteins that could bind IgE from sera of patients with allergy.


METHODS
Several brands of walnut, almond, hazelnut, 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 also examined to confirm reproducibility of immunoreactivity as reported by other investigators. Oils were extracted with 0.2 mol/L ammonium bicarbonate, and protein concentrations in the aqueous extracts were measured. IgE binding was assayed by slot-blot and Western immunoblotting. Pooled sera from patients with a history of systemic reactions to various 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 binding and higher protein concentrations.


CONCLUSIONS
Tree nut and peanut oils may pose a threat to patients with allergy, depending on the method of manufacture and processing.
Teuber
S S
SS
Department of Internal Medicine, University of California Davis, School of Medicine, USA.
Brown
R L
RL
Haapanen
L A
LA
D000485:Allergens / Q000032:analysis / Q000276:immunology*; D010367:Arachis / Q000276:immunology; D005511:Food Handling / Q000379:methods*; D006801:Humans; D015151:Immunoblotting / Q000379:methods; D007073:Immunoglobulin E / Q000097:blood; D009754:Nuts / Q000276:immunology*; D000074241:Peanut Oil; D010938:Plant Oils; D010940:Plant Proteins / Q000032:analysis / Q000276:immunology; D014197:Trees
D000485:Allergens; D000074241:Peanut Oil; D010938:Plant Oils; D010940:Plant Proteins; D007073:Immunoglobulin E