Persistence of peanut allergen-derived peptides throughout excessive dry thermal processing

Abstract

ScopeCommercial dry roasting of peanuts can result in accumulation of extensively heated peanut residue in ovens. These residues could pose a potential allergenic risk if residues are transferred to food products subsequently processed in the oven. Peanut residues can be detected in food products using antibody-based methods, but detection is greatly affected by thermal processing. We investigated the detectability of peanut allergens after excessive thermal processing using mass spectrometry (MS). Methods and resultsPeanut kernel halves were roasted in a muffle furnace, ground, robustly extracted, and probed by immunoblot with sera from patients with peanut allergy (anti-peanut IgE) and anti-peanut IgG. Extracts were further analyzed by MS. After 8 h at 176 °C, detectable allergenic protein content, by MS, decreased 54.6-fold, with surviving contiguous regions sufficient to bind IgE to Ara h 3. ConclusionsFailure to detect peanut residues with antibody-based methods should not be regarded as an indication of the absence of peanut residues as robust extractions coupled with MS were able to identify peanut from some of these processed samples. Peanut residues should be physically removed prior to thermal processing as reliable existing antibody-based methods are inadequate to detect peanut residues after extensive heating of products.